Commodore CBM 2040, CBM 4040, CBM 3040, CBM 8050 User Manual

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User's

Manual

for

GBM

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Dual

Floppy

Disk

Drives

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User's

Manua

for

CBM

Dual

Drive

Floppys

Model

2040-Model

4040

Model

3040-Model

8050

Appropriate

for

use

with:

Commodore

Computers

•

Series

2001 (CBM-PET)

•

Series

3000

(CBM)

•

Series

4000

(PET)

• Series

8000

(CBIVI)

Part

Number

320899

October

1980

commodore

©

1980

Commodore

Business

Machines,

Inc.

^ Table of Contents

Page

Chapter

1

Introduction

1

General

Information

2

Description

3

Front

Panel

3

Back

Panel

3

Interior

Configuration

4

The

Diskette

5

Specifications

5

Care Of

The

2040,3040,4040

and

8050

9

CareOfThe

Diskettes

9

Unpacking

The

Disk Drive 9

Chapter

2

PreparingToUse

Your

Disk Drive 11

Connecting

The

Disk DriveToThe

Computer

11

Performing

The

Power-On

Test

12

Inserting

The

Diskette

Into

The

8050

13

liisi!fliii|j

Till!

IJiiiktiUe

liilu

Tlie

HO-IO,

ijO-lO

uml

<10'1()..Iit

The

4040

and

8050

Performance

Test

14

The

2040

and

3040

Performance

Test

17

Chapter

3

Learning

HowToUse

Your

Floppy

Disk

Drive

21

The

Block Availability Map (BAM)

22

The

Disk Operating

System

(DOS) 22

Disk

Maintenance

Commands

23

NEW

24

HEADER (BASIC

4.0

Direct Command) 25

Initialization

(2040

and

3040)

25

Initialization

(4040)

26

Initialization

(8050)

26

The

Directory

26

LOAD$

26

DIRECTORY (BASIC

4.0

Dkect

Command) . 27

Printing

The

Dhrectory

27

in

IV

VALIDATE

28

'

COLLECT

(BASIC

4.0

Direct

Command)....

28

DUPLICATE

28

BACKUP (BASIC

4.0

Direct Command) 29

COPY

29

COPY (BASIC

4.0

Direct

Command)

31

CONCAT (BASIC

4.0

Direct Command) 31

RENAME

31

RENAME (BASIC

4.0

Direct

Command)

32

SCRATCH

32

SCRATCH (BASIC

4.0

Direct

Command)....

33

Chapter

4 BASIC

Commands

For

Data

Handling 35

BASIC

Commands

Associated

with

Floppy

Disk Drives

35

SAVE and DSAVE (Writing a Program to a

Diskette)...

36

LOAD and DLOAD (Reading a Program

from

a

Diskette)

36

VERIFY

37

OPEN

38

DOPEN

39

CLOSE

39

DCLOSE

40

Closing

The

Command

Channel

40

Closing

The

Data

Channel

41

PRINT#

41

INPUT#

42

GET#

43

RECORD#

43

Quickload Feature (BASIC 4.0) 44

Moving a Tape ProgramtoDisk 45

Chapter5

Advanced

Disk

Programming

47

Commodore DiskOperating System (DOS) 47

Disk Utility Command Set 48

BLOCK-READ

[ *

49

BLOCK-WRITE

50

BLOCK-EXECUTE 50

BUFFER-POINTER 50 ^

BLOCK-ALLOCATE

51

~

MEMORY 51

MEMORY-WRITE 51

MEMORY-READ

52

MEMORY-EXECUTE

52

USER 52

8050

Disk Zones 59

Chapter

6

Advanced

File

Handling

65

Special Open and Close Statements For Direct Access' 65

Random

Access

Example

66

To

Create

A File

66

To

AddARecord

67

To

See A

Record

68

To

Change A

Record

68

Getting The Directory of Listings 69

VI

13

14
15

16

17

Directory

Format

0q

Sequential

Format

* ]]

Program

File

Format

61

Relative

File

Format

.!!!!!!...!!!!!!.

70

User's

Quick

Reference—Disk

Commands

87

Ending The Program 69

Relative Files

4040,8050

69

CreatingA RelativeFile 72

ExpandingA RelativeFile 72
Accessing

A RelativeFile 73

Chapter

7

Simplifying

The

UseofCommodore

Disk-Related

Commands

77

Loading

The

DOS

Support

Program

77

Using

The

DOS

Support Symbols:> and @ 78

Loading A

Program

With

The / 78

LoadingAnd Running A ProgramWithUp Arrow 79
SpecialDOSSupport Information 79

Chapter8 Error

Messages

—Pattern

Matching

File

Names

—DiskCommands 81

Requesting Error

Messages:

Commodore Disk Drives 81

Summary Of CBMFloppy Error Messages 82

Description of DOS Error Messages 82

Pattern

Matching

85

User's Quick Reference: Disk

Commands

86

Chapter 9 Random 1.00 Program Listing 89

Chapter

10

Index

95

Figure

1

2
3

4
5

Table

1
2
3

4
5
6

7

8

9

10

11

12

List

of

Illustrations

Title

Page

Models 2040,

3040,4040,8050:

Rear View 5

Floppy

Disk

Hookup

12

Position

For

Diskette

Insertion

13

2040,3040,4040 Format: Expanded

View

of A

Single

Sector 62

8050

Format:

Expanded View of A Single Sector 63

List

of

Tables

Title

Page

Suggested Reading List 4

Specifications: Model8050 DualDriveFloppy Disk 6

Specifications: Models 2040/3040 Dual Drive Floppy Disk 7

Specifications: Model4040 Dual DriveFloppy Disk 8

Standard Jump Table 53

Block

DistributionByTrack

I 54

2040,3040

BAM

Format 55

2040,3040 Directory

Header

55

4040

BAM

Format

56

4040

Directory Header 56

8050 Directory Header Block 57

8050

BAM

Format

58

Chapter

1

INTRODUCTION

The disk-oriented Commodore Computer System was designed around the central concept

of providingyou, the user, with largefile-handling capabilitiessupported by

BASIC

pro

gramming commandsand further simplified by DOSSupport command abbreviations.

Read the Tableof Contentsand becomeacquaintedwith the broad scopeof material

covered

in thismanual. It hasbeen

designedtoassist

you in

pursuing

an educational pro

grambyutilizing

the

computer

asan

adjunct

to the

learning

process.

That

is,

once

the

disk

driveis properlyinterfaced to a Commodore Computer,

YOU

become asimportant an ele

mentof the

system

asthe

hardware.

Your

importance,

however,ismeasured

in directrela

tionship to how

well

you understand how to effectively utilizethe hardware

arid

software.

That's why it is best to think of your computer and disk drive as only part of a system.

Grasping

andunderstanding the concept that each

individual

component actsand reactsto

signals

and

commands

from

other

devices

inthe

system

will

greatly

accelerate

your

funda

mental

grasp

of how to operate, control, and master the system.This basicconcept forms

the

basis

of this manual: teachingyou how to gainmastery of the system so that it

will

performasdesired.

Thatisthe

primary

reason

this

manualislaid

out in a

building

block

fashion: it permits you to advance as fast as

you

desire.

The first chapters discuss basichardwarefeatures and permit you, right from the start, to

become familiar with

the

disk drive by doing the performance tests which comprise the first

essential"hands

on"

experience. Then, by actually usingyour particular disk drive and

learning to carefullyfollow instructions,you can

gain

confidencein order to proceedto

more

comprehensive

subjects.

Bythe timeyou

begin

Chapter

3—Learning

HowTo

Use

Your Floppy DiskDrive-you

will

havealready used some portions of the DOSSupport system which isnot fully described

until Chapter 7. The reason for this procedure lies within the purpose of DOSSupport:

simplifying commands. It is actually easierto instruct a new user by

using

the simplified

command structure of DOS Support than attempting to explain the entire command hier

archy at an early stage.This concept of providingyou with enough essentialinformation to
complete a task, a step-by-stepdescription of the task, and meaningfulexamples is a feature

of this manual which will provide

you

with sufficient incentivetoactually complete

the

task.

The

mannerinwhich

this

manualislaid

out

encourages

the

conceptoflearningbydoing.

Difficult

concepts

and

procedures have

been

broken

down

into

steps

that

walk

the

user

through

examples

which

provide

ample

opportunitytoexperiment

laterbyreturning

to

each

command

description. When possible,

the

command

format

has been included with

the

command description

and,

as an additional aid, a

User*s

Quick Reference has been placed in

Chapter8for

easy

access if

problems

persist.

Error

messages

are

also

presentedinChapter8where

they

canbequickly

referenced,

if

needed.

The

Error

Message discussions have

been

expandedtoinclude:

•

Howtorequest

error

messages.

•

Error

message

summary.

•

Detailed

error

message

descriptions.

For

those

users

who

have

been

reluctanttoattempt

disk programming becauseofthe

pre

sumed

degreeofdifficulty,

note

that

the

entire

disk

command

hierarchyisstructuredinthis

manual

from

least

difficulttomore

complex:

•

Commands

for

file

manipulation

and

maintenance

•

Commands

for

data

handling

• Advanced

programming

•

Advanced

hie

handling

•

Simplified

commands

Users who have attained some degree of programming skills

may

desiretobegin with

the

advanced subjects such as random access or relative files while others

maybecontent

with

just following the manual's format. In either case, this manual has been laid out to provide

the user with essentialinformation in a logicalsequence. Follow the examples,attempt the

step-by-step procedures,

and

learnbydoing.

GENERAL

INFORMATION

With

the

purchaseofyour

Commodore Dual Drive

Floppy

Disk

you

have greatly enhanced

the

computing power of

your

Commodore system.Toget

the

most

outofyour

system

you

should

study

your

computer's

user guide, and if necessary

the

BASIC manuals listed in

Table 1. You will benefit most if you first read through this entire manual, taking

note

of

those

features

that

relatetoyour

particular

floppy

as well as

those

which are

commontoall

CBM

Floppys.

The information presented in this manual is extensive and may, in some cases, present in
formation that is currently beyond your particular levelof expertise. However, by carefully

and thoughtfully studying its contents you will gain the confidence necessary to progres

sively upgrade

your

programming skills and expertise.

This manual presents discussions, descriptions, practices and procedures relating

to

the

use

and

operationofall

Commodore

5-1/4-inch Dual

Floppy

Disk Drives.

Four

models

are

discussed:

Model

2040

(DOS

1)

Model

3040

(DOS

1)

Model

4040

(D0S2)

Model

8050

(DOS

2.5)

The

floppys

are

operationally

compatible

with

the

following

Commodore

Computers.

1.

Series

2001—16K

and

32K

—Operating With BASIC Version

3.0

2. Series

2001—PET8K—UpgradedtoBASIC Version

3.0

3. Series

3000—16K

and

32K

—Operating With BASIC Version

3.0

4. Series

4000

- PET

8K,

16K,

and

32K

- Operating With BASIC Version

4.0

5. Series

8000—32K

—Operating With BASIC Version

4.0

For

ease of reference,

the

Models

2040,

3040,4040,

and

8050

Dual Drive

Floppy

Disks will be referred to in this manual as

"the

2040",

"the

3040",

"the

4040",

and

"the

8050",

respectively. All descriptions

and

discussions are

common

unless

noted

otherwise.

DESCRIPTION

All CBM

Floppys

described in

this

manual

are

dual-drive

diskette

storage

devices.

Their

individual

primary

components

consistofread/write

controls,

drive

motor

electronics,

two

drive mechanisms,

two

read/write

heads,

and

track

positioning mechanisms. All

disk

drives

discussed in

this

manual

conformtoIEEE-488

interface

requirements.

Because

each

device

is an

"intelligent"

peripheral,

their

operation

requiresnospace in

the

computer's

memory.

This means

you

have

justasmuch

computer

memory

availabletoyouaswhen

youdonot

have

the

disks

attached.

Front

Panel

The front panel of the respective disk drive consists of an identification panel across the top;

slots in whichtoinsert two diskettes; and doors to close after inserting the diskettes. When

the door isclosed, the diskette is clamped onto the diskette spindlehub. Alsoon the front

panel are three LEDindicator lights.The one on the right iscalled the Drive0 Active Indi

cator, and lights when drive 0 is active. The LED on the left does the same for drive 1. On

the 8050, the LED in the middle is a two-color power/error indicator. It is normally green,

indicating power ON but flashes red whenevera disk error occurs. On the 2040, 3040, and

4040

the

middle

LED

is activated if

power

is appliedorremoved,

and

whenever an

error

occurs.

.

Back

Panel

The

backofeach

disk

drive

containsanIEEE-488

interface

connector.

Near

the

panel's

lower edge is

the

power ON/OFF switch. There is also a "slow blow"i^fuse,and

the

AC

power

cord.

Table1.Suggested

Reading

List

Pet/CBM

Personal

Computer

Guide.

C. S. Donahue and J. K. Enger, Osborne/McGraw-Hill, 630 Bancroft Way,

Berkeley,

CA

94710

Hands-On

Basic

withaPet.

H. D. Peckham, McGraw-Hill

1979

Entering

BASIC.

J. Sack and J. Meadows, Science Research Associates,

1973

BASIC: A

Computer

Programming Language.

C. Pegels,

Holden-Day,

Inc.,

1973

BASIC

Programming.

J. Kemeny and T. Kurtz, Peoples Computer Co., 1010 Doyle (P.O. Box

3100),

Menlo Park, CA

94025,1967

BASIC

FOR

HOME

COMPUTERS.

Albrecht, Finkleand

Brown,

PeoplesComputer Co., 1010 Doyle (P.O.Box

3100), Menlo Park, CA

94025,1973

A Guided

TourofComputer Programming in BASIC.

T. Dwyer,

Houghton

Mifflin Co.,

1973

Programing Time Shared

Computer

in BASIC.

Eugene H.

Bamett,

Wiley-Interscience, L/C 72-175789

Programming Language

#2.

Digital

Equipment

Corp., Maynard, MA

01754

101

BASIC

Computer

Games.

Software

Distribution

Center,

Digital

Equipment

Corp.,

Maynard,

MA

01754

WhatdoTo

After

You

Hit

Return.

Peoples

Computer

Co.,

1010

Doyle

(P.O.

Box

3100),

Menlo

Park,

CA

94025

Basic

BASIC.

James S. Coan,Hayden Book Co., Rochelle Park, NJ

WORKBOOKS

1-5.

T.I.S., P.O. Box

921,

Los Alamos, NM

87544

Programming

the

6502.

R. Zaks,

Sybex,

1978

24 Tested, Ready-to-Run Game Programs in Basic.

K.

Tracton,

Tab Books,

1978

Some

Basic

Programs.

M. Borchers and R. Poole, Osborne &

Assoc.

Inc., 1978

Basic Programming

for

Business.

I. H.

Fotknei,

Prentice-Hall,

1977

The

Channel

Data

Book.

B. Lewis,5960 MandarinAve., Goleta, CA 93017,1978

PET and

the

IEEE

488

Bus (GPIP).

Osbome/McGraw-Hill, 630 Bancroft

Way,

Berkeley,CA 94710

Interior

Configuration

Theinterior of your floppy containstwo disk

drives.

All

the

logic

for the disk

drive

iscon

tained

within

the unit.The

mechanical

devices

are,forthe

most

part,

located

beneath

the

disk

spindles.

The

Diskette

The diskette (also known as a minifloppy, floppy diskette, minidiskette, etc.) is similar to

the

standard

flexible

disk.

There

are

several

reputable

manufacturersofthe51/4-inch

diskettes.

You

should

make

sure

that

you

buy

diskettes

for

SOFT

SECTORED

FORMAT.

Your Commodore dealer can supply your needs.

Specifications

Table 2 presents the specifications for the

8050,

Table 3

the

specifications for

the

2040

and

3040,

and

Table4the

4040.

PIGGYBACK
CONNECTION

{IEEE

PLUG

)

Figure

1 —

Models

2040,

3040,

4040,

8050:

Rear

View

ON/OFF

SWITCH

Table2.Specifications:

Model

8050

Dual

Drive

Floppy

Disk

STORAGE:

Total

capacity

Sequential

Relative

Directory

entries

Sectors

per

track

Bytes

per

sector

Tracks

Blocks

533248

bytes

per

diskette

521208 bytes per diskette

464312 to 517398 bytes per diskette

depending

upon

file size.

182880 bytes per file

65535 records per file

224

per

diskette

23to29

256

77

2083

IC's:

Controller

6502
6530

6522

microprocessor

I/O,

RAM,

ROM

I/O,

interval

timers

Interface

6502

6532(2)

6564

(2)

microprocessor

I/O,

RAM,

interval

timers

ROM

Shared

6114

(8)

4xlK

RAM

PHYSICAL:

Material

18

ga.

steel

Dimensions

Height

Width

Depth

6.5"

15.0"

14.35"

ELECTRICAL:

Power requirements

Voltage

Frequency

Power

100,117,

220, or 240 VAC

50or60

Hertz

50

watts

MEDIA:

Diskettes

Standard

mini

5 1/4",

single

sided,

single

density

^ I

o;|

i

?

1

-1}

>'1'

i

Table3.Specifications:

Models

2040/3040

Dual

Drive

Floppy

Disk

STORAGE:

Total

capacity

Sequential

Random

Directory

entries

Sectors

per

track

Bytes

per

sector

Tracks

Blocks

176640

bytes per diskette

170180

bytes

per

diskette

170850

bytes

per

diskette

152

per

diskette

17to21

256

35

690

IC's:

Controller

6504

6530

6522

microprocessor

I/O,

RAM,

ROM

I/O,

interval

timers

Interface

6502

6532

(2)

6332(2)

microprocessor

I/O,

RAM,

interval

timers

ROM

Shared

6114

(8)

4xlK

RAM

PHYSICAL:

Material

18

ga.

steel

Dimensions

Height

Width

Depth

6.5"

15.0"

14.35"

ELECTRICAL:

Power

requirements

(2040)

Voltage

Frequency

Power

120

VAC

60

Hertz

50

Watts

Power

requirements

(3040)

Voltage

Frequency

Power

100,

220,or240

VAC

60

Hertz

50

Watts

MEDIA:

Diskettes

Standard mini 5

1/4",

singlesided,

single

density

8

CSsi.

Table4,Specifications:

Model

4040

Dual

Drive

Floppy

Disk

STORAGE:

Total

capacity

Sequential

Relative

Directory

entries

Sectors

per

track

Bytes

per

sector

Tracks
Blocks

174848

bytes

per

diskette

168656

bytes

per

diskette

167132

bytes

per

diskette

65535

records

per

file

144

per

diskette

17to21

256

35

683

IC's:

Controller

6504

6530

6522

microprocessor

I/O,

RAM,

ROM

I/O,

interval

timers

Interface

6502

6532(2)

6332(2)

microprocessor

I/O,

RAM,

interval

timers

ROM

Shared

6114(8)

4xlK

RAM

PHYSICAL:

Material

Dimensions

Height

Width

Depth

18

ga.

steel

6.5"

15.0"

14.35"

ELECTRICAL:

Power

requirements

(4040)

USA

(domestic)

Voltage

120

VAC

Frequency 60 Hertz

Power 50 Watts

Power

requirements (4040)(international)

Voltage

100,

220,or240

VAC

Frequency 60 Hertz

Power 50 Watts

MEDIA:

Diskettes

Standard

mini

51/4",

single

sided,

single

density

CARE

OF

THE

2040,

3040,

4040

AND

8050

The

disk drive should be placedona fiat surface freeofvibration.Itis

important

that

dust

particles be

keptata minimum since a particle buildup will interfere with

optimum

opera

tion. If you should experience a hardware failure contact your Commodore dealer. Any

attempttocorrect

the

problem yourself could result in voiding

the

warranty.

CARE

OF

THE

DISKETTES

Handle diskettes with care. Follow these instructions to maintain the quality of the diskette

andtoprotect

the

integrityofthe

data:

1.

Return

the

diskettetoits

storage envelope whenever it is removed

from

the

drive.

2. Keep the diskettes away from magnetic fields. Exposure to a magnetic field can distort

the

data.

3. Never leave a diskette on

topofyour

computer or disk drive.

4. Do not write on the plasticjacket with a lead pencilor ball-pointpen.

Use

a felt tip pen

or fill

out

the

label before attaching it to

the

jacket.

5. Do

not

expose diskettes to

heat

or sunlight.

6. Do

not

touchorattempt

to clean

the

diskette surface. Abrasions will cause loss of stored

data.

7. Before applying power to the

2040,3040,

or 4040 open the drive doors and remove

diskettes.

UNPACKING

THE

DISK

DRIVE

Before unpacking

the

disk drive, inspect

the

shipping

carton

for signsofexternal damage. If

the

carton is damaged, be especially careful when inspecting its contents. Carefully remove

all packing material and

the

contents of the carton. DO NOT discard any packing material

until

you

have

made

sure

you

have

located

all

the

contentsofthe

carton!

The

carton

should

contain:

1.

Commodore

Dual

Floppy

Disk

Drive

2. User

Manual,

Number

320899

3.

Oneofthe

following TEST/DEMO diskettes:

a.

2040/3040/4040

TEST/DEMO diskette, P/N

4040037

b.

8050

TEST/DEMO diskette,

P/N

8050050

If

any

items are missing, please

contact

your

Commodore

dealer immediately.

NOTES

10

Chapter

^

PREPARING

TO

USE

YOUR

DISK

DRIVE

Before

startingto useyour disk

drive,

make

sureit isin

good

working

condition.Thisin

cludes

properly

connecting

it to yourcomputer,

giving

it a

power-on

and

initial

checkout

test,and

finally

the

performance

test

using

theappropriate

TEST/DEMO

diskette.

CONNECTING

THE DISK DRIVE TO

THE

COMPUTER

One

of twoconnector

cables

arerequired to interface the

floppy

to the computer.

These

cablescan be suppliedby your Commodoredealer.

1. PET-to-IEEE cable, P/N 320101

Usethis cable if the disk drive is to be the only (or first) IEEE deviceconnected to your

computer.

2. lEEE-to-IEEE cable, P/N 905080

Use

this

cable

ifyour disk

drive

isto be connected ("daisy-chained") to anotherperi

pheral

device

suchasthe

Commodore

Model

2022,orany

other

suitable

interfaced

printer.

NOTE:

Thedisk driveshould be the first peripheralattached to the computer if other de

vices

aretobe

"daisy-chained".

Follow these stepstoconnect

the

disk drivetoyour

computer:

STEP

1:

Turn

power

OFFtothe

computer.. f

STEP 2: Place

the

disk drive in a convenient location as close as possible to

the

computer.

DO

NOT

connect

the

disk

drivetoa

power

outletatthis

time.

STEP3: Connect the PET-to-IEEEcable between the IEEE-488 interface connector on the

computerand the connectoron the disk

drive.

If additionalIflEE

devices

areto

be connected, the lEEE-to-IEEE cable(s)must be used.

STEP 4: Connect the disk drive power cable to an AC outlet. DO NOT

turn

on power at

this

time.

11

CBM

Computer

iW

PET-to-IEEE

Cable

(P/N 320101)

Printer

Floppy

Disk

lEEE-to-IEEE

Cable

(P/N 905080)

Figure

2—

Floppy

Disk

Hookup

PERFORMING

THE

POWER-ON

TEST

You

are

now

readytoproceed

witli

the

poweron

partofthe

checkout:

STEa-1:

Open

both

disk

drive

doors.

Ensure

thatnodiskettes

are

presentineither

drive.

STEP

2:

power

ONtothe

COMPUTER

and

verify

thatitis

working

properly.

12

J

INSERTING

THE

DISKETTE

INTO

THE

8050

STEP

1:

Insert

the

diskette

into

the

slot

designated

"Drive0"and

with

the

write

protect

tab

oriented

to

the

left.

STEP 2: Once

the

diskette is in

the

slot, push gently on

the

diskette

until

you

hear a

dis*

tinct

"clock".

The diskette is now properly positioned in

the

drive.

STEP

3: Press DOWN firmly on

the

spring-loaded

doorofthe

drivetolower

the

diskette

into

the

correct

position. It is

importanttopress firmly on

the

door

in a

smooth

motiontoavoid damaging

the

diskette.

STEP

4:

To remove

the

diskette, press DOWN firmly on

the

spring-loaded

door.

This will

release

the

spring

and

raise

the

diskette.

Wlien

the

diskette

is level

with

the

open

ing, press UP on

the

door. This will release the diskette

and

push it

out

toward

the

frontofthe

drive.

The

disketteisnow

freetobe

removed

from

the

drive.

STEP

5:

DO

NOT

ATTEMPT

TO

CLOSE

THE

DOOR

WITHOUTADISKETTE

IN

PLACE.

The

doorislocked

openbya

mechanical

interlock

mechanism

associated

with

the

diskette

ejector

that

prevents

the

door

from

closing if no

diskette

has

been

loaded.

WRITE

PROTECT

NOTCH

WHEN

COVERED.

DISKETTE

CONTENTS

CANNOT

BE

ALTERED

3Hoaowwoo

Figure

3 —

Position

for

Diskette

Insertion

INSERTING

THE

DISKETTE

INTO

THE

2040,

3040

AND

4040

CAUTION:

NEVER

APPLY

POWER

TO

THE

DISK

DRIVE

IF

DISKETTES

ARE

PRESENT

(LOCKED

AND

SEATED)INEITHER

DRIVE0OR

DRIVE

1.

STEP1:Ensure

that

the

powertothe

disk drive is

OFF

and

DO

NOT

apply

power

until

you

complete

this

step.

Open

both

disk

drive

doors

and

make

sure

that

no

diskettes

are

presentineither

drive.

STEP 2: If

the

preceding conditions have been

met,

you

may

apply power to

the

disk

drive.

»LTtedlo

°"

tab

STEP4:Once

the

disketteisin

the

slot,

gently

pushonit

untilitis

fully

seated

"

5H~~

THE

4040

AND

8050

PERFORMANCE

TEST

SX\'rrrriryl"dL'ruty

^deit^X

Performance

^

this

point,

enter

the

commaLsTu

f "haPPe»i"gtest.

At

EXPECTED

results

are

obtained

during

any

steoS'th^f

"

™-

most

likely

causeofa

problem

ran"„rnL!'^1 .

The

until

you

become

familiar

with

your

disk

unit.^

'

command.

Thisistobeexpected

press

the

RETURN

key

oVyoi^r

ke^^^

followed

byacarriage

return:

S^in

re^xirif

th7e"^»1nd1crr

H.S"™"

example

anyway.

Re^nter

younas^c^^^^^

Tf^

'he

successful

and

you

may

continue.

^

correction

was

NOTE

FOR

BUSINESS

KEYBOARD

USERS

ONLY-

Ym.

n»„

.f

upper

case

character

entry.Dothisbytyping:

"

POKE

59468,12

and

pressing

the

RETURN

key

STEP1;Insert

the

DEMO

diskette

into

drive0as

previously

instructed.

STEP2:^pe:

LOj^

"*",8

and

press

RETURN.

The

computer

will

load

the

first

file

^^ftom

the

disketteindrive0and

display

the

foUowing:

STEP3: Type: RUN and pressRETURN.This willcausethe

DOS

Support Program to be

executed. (This program is

not

necessary for the disk unit to operate; it just

simplifies the direct mode commands.) A brief introductory descrption of

DOS

Support ispresented in Chapter 3 as it appliesto Chapter 3 operations. A de

tailed description of DOS Support is presented in Chapter 7.

STEP

4:

Insertablank

diskette

into

drive1and

type;

>N1:DEM0,99

>C1=0

This procedure formats the diskette and copys all files from drive 0 to drive 1,

thus creating a backup of the

DEMO

diskette. Remove the

DEMO

diskette from

drive 0 and returnitto its protective envelope. Remove

the

diskette from drive 1

and place it in drive 0. Close

the

door

to drive 0.

STEP 5: Type: LOAD "PERFORMANCE TEST",8

The

screen

will

display:

STEP

6:

Type:

RUN

and

press

RETURN.

The program instructs you to place a blank diskette into each drive. The Per

formance Test Program executes a shortened version of

the

test used by Commo

dore in final inspection of

the

4040or8050.

The

purpose of this test is to ensure

that

the

unit is functioning correctly and will take approximately seven minutes

to

complete.

NOTE: Do

not

use diskettes containing any valuable information since

the

Per
formance Test Program will re-format them and any data will be lost. The test
program will label these diskettes

"Test

Disk1"and

'Test

Disk

2".

These disk

ettes are ready for further use when

the

test program iscompleted and

the

per

formance

test

has

been

satisfied.

STEP 7: Press RETURN, the following will display:

STEP 8:

Enter

the

appropriate response to

the

question

and

press RETURN.

The

computer

will calculate

the

maximum number of tracks for

the

particular

disk drive

and

begin

the

performance

test.

The

screen displays:

NEW~ei

COMMFlNri

HEW-1

COMfiRHD

OK

Ci

OK 1

00.0

00.0

in drive 1.

the

screen

displays:

®

*^^1®

operation

both

IiRIVES

PfiSS

MECHRNICRL

TEST

The

computer

conducts

the

remainder

of

the

Performance

Test

and

displays;

OPEN

WRITE

FILE

ON

0

UPEN

WRITE

FILE

ON

1

writing

IiflTfl

TO

0

WRITINU

DHTfl

TO

1

CLOSE

WRITE

DRTfl

TO

1

OPpj

REflD

FILE

ON

0

OPEN

REflD

FILE

nw

1

reading

DRTfl

FROM

0

SCRATCH

FILE

ON

0

FILES

SCRATCHED

1

.5=^:RATCH

file

ON

1

files

SCRATCHED

1

WRITE

TRACKxxON

0

hdJJI

ON

1

WRITE

TRACK1ON

0

WRITE

TRACK1ON

1

RERIf

TRACKxxON

0

READ

TRACK

xx

ON

1

RERD

track

1

ON

0

READ

TRACK1ON

1

OK 0

00.

00

OK 1

00,00

OK.0

00,00

OK 0

00.

00

OK 1

00.00

OK 1

00.00

OK 0

00.

00

OK 1

00.

00

OK 0

00-

00

01.00

01,00

OK 0

00.00

OK 1

00.00

OK 0

00.

00

OK 1

00.

00

OK 0

00.00

OK 1

00.00

OK 0

00.

00

OK 1

00.00

UNIT

HAS

PflSSEIi

PERFORMANCE

TEST!

TUW^IN.i'^IJ^Po^F?'''

READV,

I

P™'-«ve

jackets.

The

floppy

has

STEP

10:

^L7/-tp:a?re

P"-

test,

return

to

a

.Msfactory

conclusion

to

the

Performanr^^:tXTct'y^^^^^^^^^^^^

THE

2040

AND

3040

PERFORMANCE

TEST

When

you

have

successfully

completed

the

Power-On

test,

proceed

with

the

Performance

Test.

Don't

worryifyou

don't

fully

understand

exactly

whatishappeninginthis

test.

At

this

point,

enter

the

commands

justtogetafeel

for

what

you

candowith

your

disk.IfUN

EXPECTED

results

are

obtained

during

any

stepofthe

test,

stop

and

start

over

again.

The

most

likely

cause

ofa

problem

isan

improperly

entered

command.

This

isto be

expected

until you become familiar with the procedure.

All

commands

entered

via

the

keyboard

mustbefollowedbacarriage

returni

Dress

the

RETURN

key.

NOTE:

Enter

the

commands

exactlyasshown.DONOT

insert

any

spaces

unless

shown

in

the

example.Ifthe

error

indicator

lights,

you

maybeabletocontinue

the

example

anyway.

Re-enter

your

last

command.Ifthe

light

goes

out,

your

correction

was

successful

and

you

may

continue.

STEP1:Insert

the

DEMO

diskette

into

drive

0 as

previously

instructed.

Insertablank

diskette into drive 1. Close both drive doors.

STEP 2: Type: OPEN1,8,15

This

command

opens

logical

file1on

device8.The

secondary

addressof15

opens

the

command

channeltothe

device.

The

screen

displays

your

entry

followed

by

READY.

NOTE

FOR

BUSINESS

KEYBOARD

USERS

ONLY:Toset

the

computer

for

upper case character entry type:

POKE59468,12 and press RETURN

Although it isnot absolutely

necessarytogive

this

command

priorto communi

cating

with

the

disk

drive,itdoes

permit

easy

entry. In addition, the

examples

in

this

manual

canbe

duplicated

exactly.

(POKE

59468,14

will

returnthe

user

to

lower case letters.)

STEP3: Type: PRINT#1,"I0"

This

command

initializes

drive0.The

initialization

procedure

places

the

magnetic

head

ofthe

drive

inthe

proper

position

above

the

diskette.

This

processisneces

sary

each

time

the

disketteisremoved

and

inserted

into

the

drive.

The

computer

displays

your

entry,

then

the

word READY.

STEP 4: Type: LOAD"*",8 and press RETURN.

The

screen

displays:

STEP

5:

Type:

RUN.

This causes

the

DOS

support

program to be executed. (This program is

not

neces

sary for

the

disk unit to operate, it just simplifies

the

direct mode commands.) A

brief

introductory

discussionofDOS

SupportispresentedinChapter

3 as it

appliestoChapter3operations.Adetailed

descriptionofDOS

Supportispre

sentedinChapter

7.

STEP

6:

Type:>D1=0

This

commands

the

disk

drivetomakeabackup

copyofthe

DEMO

diskette.

Remove

the

original

DEMO

disk

from

drive0and

returnitto

its

protective

envelope.

Insert

the

backup

disk

into

drive

0.

STEP

7:

Type:

>10

This

command

initializes

the

backup

diskette.

STEP 8: Type; LOAD"0:DIAGNOSTIC BOOT",8

This

command

loads

the

Diagnostic

Boot

program

from

the

diskette

in drive 0

into

memory.

The

screen displays

your

entry

and:

Concurrent

with

the

display,

the

drive 0

indicator

lights

and

the

drive 0

motor

runs.

STEP

9:

REMOVE

THE

BACKUP

DISKETTE

BEFORE

PROCEEDING

TO

THE

NEXT

STEP.

STEP

10:

Type:

RUN

and

press

RETURN

Follow the directions on the screen. If all three indicators flicker continuously,

the

test is passed. If all indicators remain lit in a steady

pattern,

the

directions

on the screen can be used to find

the

problem area. After 30 seconds of opera

tion, reset the disk drive by turning the computer's powerswitch OFF, then ON.

STEP

11:

Simultaneously press

SHIFT

and CLR/HOME to clear

the

screen. Use

the

POKE

command described earlier to set the computer for upper case character entry.

STEP

12:

RETURN

THE

BACKUP

DISKETTE

TO

DRIVE

0

STEP

13:

Type:

>10

This

command

initializes

the

disketteindrive

0.

STEP

14:

Type:/0:PET

DISK

This

loads

the

PET

DISK

program

from

the

diskette

in drive 0

into

memory.

The

screen displays

your

entry

and:

STEP

15:

Type:

RUN

The

PET

DISK

programisdisplayed

until

terminated.

Note

that

you

can

hear

the

drive0motor

running

intermittentlyaseach

program

loads

the

next.

STEP

16:

Press

the

RUN/STOP

key.

Simultaneously

press

SHIFT

and

CLR/HOME. This

completes

the

2040

and

3040

performance

test.

NOTES

Chapter

3

LEARNING

HOW

TO

USE

YOUR

FLOPPY

DISK

DRIVE

Your

CBM

Floppy

Disk

Drive

adds

and

enhances

your

computing

power

with

added

storage

andfilehandling capability and iscontrolled directly with:

• BASIC commands entered via

the

keyboard,

• BASIC

statements

within programs,

and

• special disk commands.

In

this

chapter

you

will

learn

howtoapply

those

commands

and

statements.

This

chapter

is

organizedinsuchaway

that

the

functions

and

formatofdisk

commands

are

describedina

manner

which

permits

the

usertoperform

disk-related

tasks.

For

BASIC

4.0

users,

those

BASIC

commands

which

correspondtoeach

disk

maintenance

command

are

also

discussed.

Before

using

your floppy disk makesure you know howto:

1. operate your Commodore Computer,

2. do elementary programmingin

BASIC,

and

%

3.

open

and close files.

NOTE:

The

BASIC

statements

described

inthis

chapter

apply

specifically

to the

2040,

3040,4040,

and

8050.

Certainofthe

commands

and

statements

may

followaslightly

dif

ferent

formatorproduce

different

results

from

those

described

herein

when

they

are

used

with

the

computerorwith

other

peripherals.

Consult

the

appropriate

manual

for

the

exact

usageofthese

commands

and

statements

inother

applications.

This

chapter

will

first

acquaint

the

user

with

those

fundamental

disk

commands

that

per

form

disk

maintenance

and

file

manipulation

and

will

then

progressively

advance

toward

an

understandingofthose

BASIC

commands

used

for

data

handling.

Approachedinthis

man

ner,

the

user

will

then

have

developed

the

necessary

confidence

and

programming

skills

to

proceedtoadvanced

disk

programming

techniques.

Practice

the

disk

commands,

read

the

examples,

and

follow

the

step-by-step

illustrationsoftheir

usage.

The

understandingofthe

more

advanced

disk

programming

techniques

will

depend

to a

large

degree

upon

how

well

the

fundamentals

have

been

mastered.

21

Tofacilitate your

understanding

and

masteryofCommodore

BASIC,

twocomputer

terms

are

stressed

inthis

Chapter:

Block

Availability

Map

(BAM)

and

Disk

Operating

System

(DOS).

Although

these

are

conventional

terms,

they

willbebriefly

discussedasthey

relate

to

Commodore

Floppy

Disk

Usage.

§ \

THE

BLOCK

AVAILABILITY

MAP

(BAM)||

The

BAM

isa

disk

memory

representation of

available

and

allocated

space

ona

disk.

When

the

system

stores

information

ona

disk,

the

BAM

willbeautomatically

referencedbythe

DOStodetermine

what

spaceisavailable

and

how

many

blocks

canbe

allocated.Ifsuffi

cient

spaceisavailabletostoreagiven

file,itwillbestored

onthe

disk

and

the

BAM

updatedtoaccount

for

the

space

allocated.

However,

ifthe

DOS

detects

thata

file

will

occupy

more

space

than

available,

anerror

message

willbegenerated.

Formattingadisk

creates

the

BAM

which

isthen

loaded

into

DOS

memory

upon

initializa

tion. The

BAM

isstored on diskette in varying locations dependingupon the driveused:

Model BAM Location

and

Memory Requured

2040,3040,4040 Track18, Sector0

128

bytes

8050

Track

38,

Sector 0

and

1

2

Blocks

As

changes

occur

to the

BAMinDOS

memory,

the

BAMondisk

will

beupdated to

reflect

these

changes.

Updates

to the

BAM

occur

whenaprogramissaved

ora

CLOSEorDCLOSE

is

performed

ona

new

RELativeorSEQuential

data

file.

Since

the

8050

hastwo

blocks

available

for the

BAM,

onlyone

block

of the

BAMisloaded

into

memory

at a

time.

When

updated, this

block

iswritten to the

disk

andthe other

block

loaded

into

memory.

This

interchange

ofinformation

between

the two

BAMs,

onein

DOS

memory

andthe otheron

disk,

enables

the

systemtomaintainarecordoffree

and

allocated

space

onthe

disk.

Thisdescription of the

BAM

can only stressthe importanceof initializationwhen

using

either

the

2040or3040.

Strict

attentiontothis basic rule will enable

the

usertobenefit

from the advantages of developmg good programming techniques as wellas to develop a
better understandingof the relationship of one elementof the systemto another.

THE

DISK

OPERATING

SYSTEM

(DOS)

The

DOSisresponsible

for

managing

information

exchange

between

the

disk

controller

and

the

computer.

The

DOS

performs

many

functions

which

are

transparent

to the

user

but

which

are

vital

to

the

operation

ofthe

system.

For

example,

the

DOS

monitors

theinput/output

(I/O)

ofthe

disksothat

channels

areproperly

assigned

andthat no

lengthy

waits

foran open

channel

occur. In addition to monitoring of disk I/O, the DOSalso usesthe channel structure to

search

the

directory andtodelete and copy files.

There is another function of DOS called DOS Support which was used during

hardwue

checkoutinChapter2.Review

the

Performance

Test

procedure

and

observe

the

special

sym

bolsof

DOS

Support

which

were

used

to duplicate and initialize the

disks

beforethesepro

cedures

were

fully

explained

to the

user.

Because

ofits

easeofuse,

DOS

Support

symbols

-

22

were

easiertoimplement

at that pointthanattempting to

explain

the

programming

pro

cedures

they

replace.

It is

now

appropriatetobriefly

discuss

how

DOS

Support

can

enhance

and

simplify

your

knowledge

of operating your

Commodore

computer.

Thefirst

file

on the

TEST/DEMO

diskette that

comes

withyourdisk

drive

isthe

Universal

Wedge

program,

often

referred

to as

DOS

SUPPORT.

This

program,

when

loaded

into

com

puter memory, permitsthe userto enter abbreviations for manydisk commands.

For

example,

disk

commands

which

would

normallybetransmitted

to the

disk

using

the

PRINT#lfn

"commandstring"

format

maybetransmitted

via

DOS

SUPPORTbypreceding

the

command

with

> or

Typing

slash

(/)

followed

bya

program

name

and

RETURN

will

cause

DOS

SUPPORTtoload

that

program

into

memory.

Replacing

certain

disk

commands

with

DOS

Support

special

symbols

can

simplify

learning

about

your

Commodore

computer

by

providingafaster

methbdtocommunicate

virith

the

disk.

Chapter7contains

detailed

instructionsconcerningthe useof these special symbolsand their limitations.

DISK

MAINTENANCE

COMMANDS

The

following

disk

commands

permit

the

usertoperform

file

manipulation

and

disk

maintenance.

BASIC

COMMAND

NEW

INITIALIZE

LOAD"$0"

.

VALIDATE

FUNCTION

Formatsadisk

Prepare

diskette

for

use

Read

disk

directory

Reconstruct

Block Availability

Map

(BAM)

BASIC

4.0

DIRECT

COMMAND

HEADER

Diskette

Level

File

Level

DUPLICATE Duplicates a

diskette

COPY

RENAME

SCRATCH

Copies

files

(optional

concatenation)

Renamesafile

Erasesafile

DIRECTORY

COLLECT

BACKUP

COPY

CONCAT

RENAME

SCRATCH

NOTE:

Diskettecommands can be transmittedto the disk by PRINT#commands or

through

the

abbreviated

conmiandsofDOS

support. The

examples

in thischapter

assume

that a

file

has

been

opened

with

the

OPEN

15,8,15

command.

If the

error

message

?FILE

OPEN

ERROR

appears

upontyping the

OPEN

command,itmeans

that the

logical

file

was

opened but had not beenproperly

closed.

Thiserrorcondition

will

automatically

close

the

file. To recover, retype

the

OPEN command.

23

NEW

Each time a diskette is placed in one of the drives, both the diskette and the drive must be ^

prepared

for

use. A previously

unused

diskette

must

fkstbeformattedinthe

soft-sector

format recognized by your particular disk drive. This may be accomplished by use of the

NEW

disk

command.

To use the

NEW

command,to format the diskette and initializethe diskdrive,enter the

command:

PRINT#15,"commandstring"

where 15 is the logical file number of a file which has been opened to the disk command

channel (primary address 8, secondary address

15).

The

format

of

NEW

is:

"NEWdr:fn,xx"

or

"Ndr:fn,xx"

Where dr=the drive number, 0 or 1

fn=the filename you

wishtoassign

to the disk. It may be up to 16

characters

long.

xx=a unique two-character,alphanumericidentifier supplied by the user.

The NEWcommand (with ID specified) is used on an unformatted diskette or one which the

user

wishes

to reformat.

NEW

creates

the

block

headers,

writing

the

sync

characters,

disk

ID,and track and sector numbers at the

beginning

of eachblock.The directory header

and

the

BAM

arecreated and the diskette is

made

readyto acceptdata.The

command

maybe

used

on an

ahready

formatted diskette (with no IDspecified) to clearthe diskdirectory

and

reinitialize the

BAM,

deallocating all blockson the diskette.The time

involved

in refo?^\t-

ting without an ID ismuch less

than

formatting with an ID.

Example 1: OPEN15,8,15

PRINT#15,"NO:TESTDISK,88"

TTiese

commands will open the command and error channel to the disk drive and format a

disk in drive 0, givingita disk identiferof88.

Kerens

an example of reformatting a diskette using the NEWcommand and no disk ID.

Example 2:

0PEN1,8,15

PRINT#1,"N0:NEWNAME"

The diskette willbe

assigned

the name

"NEWNAME"

and the directory and

BAM

willbe

cleared. This procedure will work

onlyifthe

diskette has been formatted.

The

NEW disk command SHOULD NOT be confused with

the

NEWcommand in BASIC.

The latter willdelete the program currently in memory and clear all variables before enter-

mganew

program.

24

HEADER

(BASIC

4.0

Direct

Command)

The

HEADER

command

has

the

same

effectasNEW

command

butisreserved

for

those

computers

using BASIC

4.0.

Since formatting destroys all

data

previously stored,

the

HEADER command has a built-in safety feature

that

queries

the

user: ARE YOU SURE? A

positive response to this question permitsformatting to take place while a negative response

aborts

the

operation.

The

formatofHEADER

command

is:

HEADER"fn",Ddr,Ixx

Where: fn=file name suppliedbyuser

but

limited to16characters.

dr=drive number, 0 or 1

xx=a unique two character alphanumeric identifier (ID) supplied by user.
(same parameters as used by NEWcommand)

Initialization

(2040

and

3040)

Whenever a diskette is inserted into either drive, for any reason, it MUSTbe initialized to

ensure

that

the

information on

the

BAM (in

the

disk memory) is

the

proper information for

the diskette currently in

the

drive. Failure to properly initialize a diskette each time it is

insertedorreinserted

into

the

drive will

resultina

DISKIDMISMATCH

ERROR

and/or

lossofdata.

Insert

the

diskette

into

drive1and

initializeasfollows:

OPEN

1,8,15

PRINT#1,"I1"

NOTE: FILE OPEN ERROR could occur if a previously opened file was addressed with a
second OPEN command. If the file is still open,

the

second OPEN command would close

the

file. If this error is displayed, retype the OPEN command and proceed.

The diskette in drive 1 isnow initialized.Do not confuse formatting and initialization.

Remember that formatting is usually a one-timeoperation and that re-formattinga disk will

destroy previously

stored

data.

The INITIALIZE command on

the

2040 and 3040 aligns

the

read/write head with track 1

on the specifieddiskette. It then movesto track 18, reads the disk label and ID, and loads

this information into

the

Disk Operating System (DOS) memory.

Sincethe 2040 and 3040 initialization function depends upon a change of ID to detect a

changeof diskette, inserting a diskette with an ID identical to one previously used may lead

to a loss of data. This happens because

the

computer will reference

the

BAMleft over from

the previous diskette. Sincethe IDsare identical the DOSassumes there has been no change

of diskette. A SAVEor DSAVEcommand may now cause new data to be written overgood

data

ahready

present on the disk because the DOS will use the old map of availablestorage

area, instead of the current one. The results are unpredictable, and the diskette may become

totally

useless.

For this reason, unique disk IDs must be used whenever possible for each

diskette.

25

Initialization

(4040)

Tlie

4040

utilizesaDOS2software

routine

each

time

the

diskisaddressedtodetermine

if

initializationisrequired.Ifa

differentIDis

detected,

the

4040

will

automatically

initialize

the

new

disk.

Operator

initializationisnot

requiredifunique

IDs

are

assigned

each

diskette.

Initialization

(8050)

The

8050

utilizesahardware

featuretodetect

the

removalorinsertionofa

diskette,soit

is

not

necessarytoinitialize

since

this

isan

automatic

function.

THE

DIRECTORY

Confirm

that

the

newly

formatted

disk

has

the

correctIDand

disk

namebyusing

one

of

the

following

methodstolist

the

directory.

The

directory

display

includes

the

following

information:

•

Disk

name

•

Disk

ID

•

DOS

version

number

•

File

name

•

File

type

•

Numberofblocks

used

•

Pointertofirst

blockoffile

• Number of available (free) blocks

There

are

two

methods

availabletoall

users

for

listing

the

directory.

The

first

method

illus-

trates

the

listing

procedure

using

LOAD

and

the

second,

the

listing

proceduremBASIC

4.0

using

the

DIRECTORY

command.Ifusinga2040or3040,

and

have

removed

the

disks

from

the

drives

for

any

reason,

the

disks

mustbeINITIALIZED

before

attemptingtodis

play

the

directory.Ifusinga4040or8050,

initializationisnot

required-insert

the

diskette

and

continue.

This

procedure

will

destroy

any

program

currentlyincomputer

memory

when

the

directory

is

LOADed.

(Refertothe

descriptionofthe>$DOS

Support

commandinChapter7which

isa non-destructivedirectory display procedure.)

STEP1:Placeaformatted

diskindrive1.If

usinga2040or3040,

INITIALIZE

the

disk

ette

and

continue.

STEP2:Type:

L0AD'*$1",8

then

press

RETURN.

The

screen displays:

STEP 3:

Type:

LIST

The

directory

for

drive1willbedisplayed.

Substituting$0for$1in

the

format

will

display the directoryfor

drive

0.

DIRECTORY

(BASIC

4.0

Direct

Command)

This command will display

the

directory

without

disturbing

the

contentofthe

memory.

You

may

type:

DIRECTORY DOusing

the

full word spelling

but

the

preferred

short

format

is illustrated which uses

the

first two unshifted characters followed by a shifted R.

To display

the

directory,

type:

diRdO and press RETURN.

If using upper case display, type:

DI_DO

and press RETURN.

The

_ in

this

example

represents

the

upper

case display

forashifted

R. Typing DI _ D1 will

display

the

directory for drive1.Typing DI _orDIRECTORY will display

the

directory for

both

drives if

there

is a

formatted

diskette

present in each drive. See

your

BASIC

4.0

reference manual

foracomplete

descriptionofthis

BASIC

command.

Printing

The

Directory

Quite often, it becomes convenienttoaffix a diskette directory listing directly on

the

pro

tective jacket. This permits

the

usertoscan

the

printed directory listing

without

having

to

insert

the

diskette

into

the

drivetoobtain

this information. Should

you

desiretoprint

the

directory, place

the

diskette in drive 0 and

enter

the

following commands:

LOAD

"$0",8

Loads

the

directory.

OPEN 4,4:CMD4 Opens device 4 (printer) and changes

the

primary

output

deviceto4.

LIST Prints

the

directory.

PRINT#4:CLOSE4 Returns

outputtothe

screen and closes the file.

VALIDATE

The

VALIDATE

command

traces

through

each

blockofdata

contained

in all filesonthe

diskette.Ifthis

trace

is successful, a

new

BAM is generated in

the

disk

memory

and

written

to

the

diskette.

Any

blocks

which

have

been

allocated

but

are

not

associated

with

a file

name, as in the caseof direct accessfiles will be freed for use. This will not affect relative

files created using

the

BASIC

4.0

DOPEN

command.

In additiontoreconstructing the BAM, VALIDATE deletes files from

the

directory

that

were never properly closed. If a READ error is encountered during a VALIDATE,

the

operation

aborts

and

leaves

the

disketteinits

previous

state.Ifa

VALIDATE

error

does

occur,

you

must

re-initialize

before

proceeding.

The

format

of

VALIDATE

is:

PRINT#15,"VALIDATEdr"

Where: dr=drive

number(0or

1)

27

NOTE:

You

may

abbreviate

VALIDATEtoV.

Ifa

drive

numberisnot

specified,

the

disk-

^

ette in the last driveused during the current session is verified.

Example:

0PEN1,8,15

PRINT#1,"V0"

or

PRINT#1,"VALIDATE

0"

COLLECT (BASIC

4.0

Direct

Command)

The

COLLECT

commandinBASIC

4.0

performs

the

same

function as

VALIDATE.

Either

command will accomplish

the

following:

• Recreate a BlockAvailability Mapaccordingto validdata on disk

• Delete filesfrom the directory which were never properly closed.
(OPENedbut never CLOSEed)

The

formatofCOLLECT

is:

COLLECT

Dx

Where: x=drive

number(1or

0)

Example

1:

COLLECTDl

Verifies

drive

1

Example 2: COLLECT

Verifies

drive

0

(drive defaultsto0)

DUPLICATE

The

DUPLICATE

command formatsthe destinationdiskette and transferseach blockof in-

formation

from

the

source

diskette to thedestination diskette, thus

creating

anexact

dupli-

cate of the source diskette. Usethis procedure for one method of creatinga backup copy of

a

diskette.

Due

to the

various

formatting protocols

usedbyDOS1,DOS

2, and

DOS

2.5,thiscom

mand

may

NOTbeused

interchangeably

when

using

diskettes

preparedondifferent

disk

drives. Use the following guidetoavoid confusion:

DUPLICATE

command

may

be used on—

• a 2040 or 3040 usingdiskettes formatted on a 2040 or 3040.

• a 4040 usingdiskettes formatted on a 4040.

DUPLICATE command

may

NOT be used on—

• a 2040 or 3040 usingdiskettes formatted on a 4040.

• a 4040

using

diskettesformatted on a 2040or 3040.

To

reproduceadiskette

under

these

conditions,

use

the

COPY

ALL

DISK

pro

gram

found

onthe

TEST/DEMO

diskette

which

came

with

your

disk

drive.

28

The

format

of

DUPLICATE

is;

PRINT#lfn,"DUPLICATEddr=sdr"

Where:

ddr^is

the

destination

diskette

(either 0or1)

sdr=is

the

source

diskette

(either 0or1)

Do

not

reverse

the

orderofthe

drive

numbers.Ifyou

do,

you

will lose all

data

and

there

is

no waytorecover

it.

Observe good practice and place a write

protect

tabonthe

diskette

containing

the

valuable

information.

This

procedure

will prevent overlaying good

information.

Example:

0PEN1,8A5

PRINT#1,"DUPLICATE0=1»

or

PRINT#1,"D0=1"

NOTE:

The

letter

D is a legal

abbreviation

for

DUPLICATE

command.

BACKUP

(BASIC

4.0

Direct

Command)

The BACKUPcommand in BASIC4.0 performs the same function as DUPLICATE.

The

format

of

BACKUP

is:

BACKUP

Dsdr

TO

Dddr.

Where: ddr=is

the

destination drive (either 0or1)

sdr=is

the

source drive (either 0or1)

Note

that

the

formatofBACKUP

differs

from

DUPLICATEinthat

the

orderofthe

drives

is

reversed.

Example: BACKUP D1 TO DO

This has exactly

the

same effect as

the

previous example given when discussing DUPLICATE

command.

For

a complete explanation of the BACKUP command, refer to

the

Commodore

BASIC

4.0

Reference

Manual.

COPY

The

COPY

command

allows

youtocopy

files

from

one

diskettetoanother,tocreate

mul

tiple

copies

(under

different

names)offilesonthe

same

diskette.

This

command

can

also be

used

to

concatenate

data

filesonthe

4040or8050.Upto

four

soiuce

files

canbecon

catenated

into

the

destination

file.Onthe

4040or8050

all

files

from

one

drive

may

be

copiedtoa

formatted

disketteinthe

other

drive.

The

COPY

command

maybeabbreviated

withaC.

COPY disk

conmiand

canbeformatted

three

ways depending

upon

application:

To

copy

a single fUe:

PRINT#lfn,"COPYddr:dfn=sdr:sfn"

29

or ^

PRINT#lfn,"Ckldr:dfn=sdr;sfn"

To

concatenate

and

copy:

PRINT#lfn,"COPYddr:dfn=sdr:sfn,sdr:sfn

.,.

or

PRINT#lfn,"Cddr:dfn=sdr:sfn^dr:sfn

...

To copyaUfUes

on a PRINT#lfn,"COPYddr=sdr"

diskette:

or

PRINT#lfn,"Cddr=sdr»

Where:

ddr=is

the destination

drive.

Thefileisto becopiedonto the diskette in this

drive. This

maybethe

same or different from

the

source drive.

dfn=is the destination file name. This name may be either a new name or the

same as

the

old file name unless

the

ddr is

the

same as

the

sdr. If

both

files

are to exist on thesame diskette, they must have different names.

In example 1, a file is copied from the diskette in drive 1tothe diskette in drive 0. In

example2,files

from

both

drives

are

concatenated

intoafileondrive

1.In

example3,all

files

from

drive0are

copiedtodrive1.An

error

message

FILE

EXISTS

willbegenerated

in

the

disk

unit

ifa

file

to be

copied

ahready

exists

onthe

destination

drive

(drive

1in

this

example).

Example 1: PRINT#1,"C1:ACCT1=0:ACCT"

A file is copied from

the

diskette in drive 1todrive 0.

Example

2:

PRINT#1,"C1:JDATA=1:ACCT1,0:ADATA,0:BDATA"

Files from both drivesare concatenated into a file on drive1. Note that file namesshould

beshort, as the

maximum

lengthof a disk

command

stringis40 characters.

Example 3: PRINT#1,«C1=0"

All files from drive 0 are copied

to

drive 1.

Example 3 illustrates one way to upgrade from a 2040 or 3040 formatted diskettetoa 4040

format:

place

a formatted diskette in drive1 and the diskette to be upgraded in drive0 and

copy

all files

from0onto

1.

30

COPY (BASIC

4.0

Direct Command)

The

COPY

direct

commandinBASIC

4.0

performs

the

same

functionasCOPY

disk

com

mand

and its format is

also

dependent uponapplication.

Use this formattocopy

the

contents of the entire disk:

COPYDsdrTODddr

Usethis formattocopy a singlefile:

COPY

Dsdr,"sfn" to Dddr,"dfn"

Where:

sdr=the

source

diskette

ddr=destination

diskette

fn'^^ile

name

CONCAT (BASIC 4.0 Direct Command)

The

CONCAT

direct command in

BASIC

4.0 permitsthe userto concatenate

files.

The

formatofCONCAT

is

CONCAT

Dsdr,«sfn" TO Dddr,"dfn"

where

the filenameddfn on driveddr

will

containthe contents of both dfn and sfn after

the concatenation.

For

example:

CONCATDO"YOURFILE" TOD1,"MYFILE"

^

will

resultinMYFILEondrive1containing

thedata

from

theold

MYFILE

and

from

YOURFILE.

YOURFILE

will

remainunchanged.

NOTE:

The concatenationfeature of

COPY

diskcommandand

CONCAT

direct command

are valid

only

for

DOS

2.

For

further

information

regarding

useofBASIC

COPY

and

CONCAT

commands,

refer

to

the

Commodore

BASIC

4.0

Reference Manual.

RENAME

The

RENAME

command

renamesanexisting

file.Afile

can

not

already

exist

with

the

file

name

specified

inthe

command

or the FILE

EXISTS

error

message

will

begenerated.

The

formatofRENAME

is:

PRINT#lfn,"RENAMEdr:nfn=ofn»

Where: dr=the disk drive on which the diskette is located.

nfn=the

new

nameofthe

file.

31

ofn=the

old

nameofthe

file.

lfn=a

logical

filenumber.You

assign

thisnumberarbitrarily and it maybe any

whole

number

between1and

255.

NOTE: The letter R is a legalabbreviation for RENAME.

RENAME (BASIC

4.0

Direct

Command)

The RENAMEdirect command in BASIC4.0 performs the same function as RENAME disk

command.

The

format

is:

RENAME

Ddr,"ofn"

TO

"nfn"

NOTE:Closeany open files before usingthe

RENAME

commandsincethe disk willnot

execute

this

commandonany

active files.

For further information on the RENAMEcommand, please refer to the Commodore BASIC

4.0

Reference

Manual.

SCRATCH

The SCRATCH command erases unwanted files from

the

specified diskette and its directory.

You can eraseone file, severalfiles, or all the files on a diskette.

The

formatofSCRATCH

is:

PRINT#lfn,"Sdr:fn,dr:fn

...

dr:fn"

Where:

dristhe

disk

drivetobe

searched.

: alonemeans"last driveaccessed",with dr refers to the specified drive,where

not

used

means

"both

drives".

fnisthe

nameofthe

filetobe

erased.

To erase one file, enter the entire name of the file:

Example: PRINT#1,"S0:ACCT"

To eraseseyeralfiles with unrelated names, enter the entire name of each file to be deleted:

Example: PRINT#1,"S0:ACCT,0:CUSTOMER,0:INV"

To erase several files at one time where names have something in common, refer to the rules

in APPENDIX B concerning

pattern

matching.

Youmay

erase

all

files

on a diskette

using

pattern matching asin the following example:

Example:

PRINT#1

"SO:*"

32

n

i

SCRATCH (BASIC

4.0

Direct

Command)

SCRATCH

direct command in

BASIC

4.0 performs the samefunction as SCRATCH disk

command.

The format is: SCRATCHDdr,"fn"

Where:

dr=drive

number

fn=filename

of

filetobe

scratched

Pattern

matching

rules

maybeused

with

this

command.Aswith

the

HEADER

command,

there

isa

built-in

safety

feature

that

queries

the

user:

ARE

YOU

SURE?Apositive

response

permits

the

file

to be

SCRATCHed

whileanegative

response

abortsthe operation.

Fora

complete

description

ofthe

SCRATCH

direct

command,

please

refertoyour

BASIC

4.0

reference

manual.

NOTES

33

NOTES

•

34

n

Chapter

4

BASIC

COMMANDS

FOR

DATA

HANDLING

BASIC COMMANDS ASSOCIATED WITH FLOPPY DISK DRIVES

The

BASIC

commands

described

inthischapter,

allow

the

usertocommunicate

withand

transfer

datatoand

from

the

disk

drive.

These commands are available for ALL versions of Commodore BASIC:

0PENlfn,8^,"dr:fn,t^/w" VERIFY"dr:fn",8

CLOSElfn

PRINT#lf

L0AD**dr:fn",8

GET#lfn

SAVE"dr:fn",8

INPUT#

These

commands

are

available

ONLYinBASIC

4.0:

DOPEN#lfn,"fn"

DSAVE"fn"

DCLOSE#lfn RECORD#lfn,R,B

DLOAD"fn"

Where:

lfn=logical

file

number

(any

number

between

1 and255)

fn=file name supplied by user

x=dr=disk drive number (1 or 0):

both

Dx and dr default to 0

8=device

number(8 for disk,2 for second cassette, 4 for printer)

sa=secondary

address

lf=logical file

All

upper-case

characters

shown

in formatare

essential

for the properexecution of a com

mand

and

must

betj^ed by

user.

These

commands

are

entered

via

the

keyboard

using

un-

shifted

characters

o^y.Onthe

CBM

Business

Model

they

will

appearinlower

case.

B^IC

3.0

commands

are

upward

compatible

with

BASIC

4.0

commands.

Each

command

willbedefined

along

withabrief

exampletoillustrate

their

use.Assoonasyour

dual

drive

floppy

diskisattachedtoyour

computer

and

has

passed

the

performance

test,weencourage

youtotry

the

examples and procedures.

35

SAVE

and

DSAVE

(WritingaProgramtoa

Dislcette)

^

Ifapropamisin

computer

memory,itcanbemovedtoa

diskette

for

storage.

This

is

accomplished

with

the

SAVE

(any

Commodore

BASIC)orDSAVE

(BASIC

4.0)

commands.

transferred

w^h

the

SAVEorDSAVE

commands

are

automaticaly

designated

by

the

DOSasa

program

(PRG)

file.

Both

commands

transfer

PRO

files

from

the

computer's

memorytothe

specified

diskette.

You

must

specify

the

drive

number,

the

program

name.

Md

the

device

number.

The

device

number

will

defaulttodevice1whichisthe

tape

unit

if

ItISnot

specified.

TTie

formatofSAVE is:

SAVE"dr.fn",dn

Where:

dr=is

the

disk

drive

number.Itmustbe0or1.

fn=is

any

file

nameof16

charactersorless

you

wishtoassigntothe

filetobe

transferred

to the diskette.

Blanks

are

countedascharacters.

dn=is

the

device

numberand it must be8.

This

following

example

illustrates

creatingaone

line

program,

SAVEinciton

the

disketfp

in

drive0under

the

name

TESTPROG,

and

VERIFYing

thatitL

rfsMeX

dtek

Example:

10?'THIS

IS A TEST"

SAVE"0:TESTPROG",8
VERIFY"0:TESTPROG",8

The

DSAVE

command

performs

the

same

functionasSAVE,

butisvalid

oniv

withaCom.

modoredisltsystem and

BASIC

4.0.

The

format

is:

DSAVE"fn"Ddr

Tliis

command

wiU

saveafile

named

"fn"onthe

floppy

diskindrive0or1.The

fUe

name

"fn",

maybeany

name

of16

charactersorless.

«" ora. ine

rue

name,

LOAD

and

DLOAD

(ReadingaProgram

fromaDiskette)

IrB^clo^lS^'Sc'4S

The

LOAD

and

DLO^

commands

transfer

PRG

fUes

from

the

specified

diskettetothe

""s'specify

the

drive

number,

the

program

name,and

the

device

LO^

is^

device

number

will

defaulttounit1whichisthe

cassette

unit.

The

format

of

LOAD"dr:fn",dn

Where:

dr=is

the

drive

number

from

which

you

are

loading

data.Itmustbe0or1.

36

fn~is

the

file name previously specified in the SAVE command and/or stored in

the

disk

directory.

dn=is

the

device

number

anditmustbe8.

The following example illustrates how a program is loaded from the diskette into the com

puter memory, then executed. To do this example, first type

NEW

and depress RETURN

key to clearyour computer's memory so that you can see that it really works. Don't con

fuse

the

NEW

commandinBASIC

with

the

NEW

disk

command

usedtoformat

your

disk.

Example

1:

LOAD*'0:TESTPROG",8

READY.

RUN

THISISA

TEST

The DLOAD command transfers performs the same function as LOAD,

but

is specifically

designed for a Commodore disk unit using BASIC4.0. The device number will default to 8

if

not

specified.

The

drive

number

will default to 0 is

not

specified.

DLOAD"fn",Ddr

A successful LOAD or DLOAD closes all open files. Therefore

you

must

give a new OPEN

commandinorder

tocontinue

communicating

with

the

disk

drive

command

and

error

channel.

The

format

of

VERIFY

command

is:

VERIFY"dr:fn",8

This

command

verifies

that

a file

named

"fn"

storedona

floppy

disk

contains

the

same

information which is stored in

the

computer's

memory. This command is

the

same as

the

VERIFY

command used with the

tape

cassette. Once again, dr refers to

the

drive number,

either

zeroorone.

Note

that

the

format

of this

command

specifies

that

the

drive

number

be

placed before the filename. The 8 at the end of this command is the devicenumber (8 for

disk, 2 for second tape cassette).

STEP 1: Writea short program and save it on a diskette in drive 1 under the name

"test"

using

the

procedure described under the section on SAVE.

NOTE: It is

important

that

the

program in memory is

not

changed in

any

way

between

the

save

and

verify

operations.

STEP 2:

Type:

VERIFY

"1:TEST",8

Once

verified,

the

screen displays:

...

Ka

verify

error

occurs,

reSAVE

the

program

and

verifyitagain.

VERIFY may also be used in the format:

VERIFY"*",8

in

ordertoperform

verificationofthe

last

fUe

saved

without

re-typing

the

fUename.

Con-

firm by following these steps:

STEP1:Write

a short

program

and

save

it.

STEP

2: Clear

the

screen.

STEP3: Type: VERIFY 8

The

VERIFY

function

willbeperformed

comparing

the

last

file

savedtothe

content

of

memory.

OPEN

^

This

command

setsupa

correspondence

betweenalo&cal

fUe

number

and

a

on

disk.Italso

reserves

the

buffer

space

within

the

disk

unit

tor

operationsonthe

file

bemg

opened.

The

format

ofthe

complete

OPEN

command

is:

OPENlfn,dn,sa,"dr:fn,ft,mode"

Where: lfn=the logicalfile number

dn=the

device

number; in this case8

sa=the

secondary

address.Itmaybeany

number

from2to14and

maybeused

either

for

inputoroutputasspecifiedinmode.

See

note

below

dr=the

drive

number:

0 or 1

fn=the

nameofthe

file.

ft=the

fUe

type.ItmaybeSEQ

(for

sequential),

USR

(for

user),

REL

(for

rela-

tive)or

PRG

(for program).

mode

describes

how

the

channelistobeused.Itmaybeeither

READ

(R)

or

WRITE

(W).

NOTE:

Secondary

address15is

the

command

and

error

channel

and

has

speci^uses

which

are

discussedinsubsequent

chapters.

Secondary

addresses0and1are

reservedbythe

operating

systems

(BASIC

and

DOS)

for

LOADing

and

SAVEmg

programs.

Examples:

OPEN2,8,2,"0:FILE1,SEQ,WRITE

OPEN3,8,9,"l:TESTDATA,PRG,WRITE*?

OPEN8,8,8,"0:NUM,USR,READ*'

^ ^ ' ^

38

p»,i•!.••;••

•-1

The

contentsofan

existing

file

(on

4040

and

8050

only)

maybereplacedbypreceding

the

drive

number with an at sign

(@)

in the OPENcommand.

OPEN3,8,5,"@0:JDATA,USR,WRITE''

If

the

specified

file

does

not

exist,

then

normal

OPENing

procedures

are

executed.

You

can

also

assign

someofthe

OPEN

parameters

toa

variable

nameasillustratedinthese

examples:

Example

1: FL$="0:FILEA,SEQ,READ"

OPEN1.8,14,FL$

Example 2:

FL$="0:FILEA"

0PEN1,8,14,FL$+",SEQ,WRITE"

The

preceding

methods

are

convenient

whenitis

necessarytoopen

several

channels

to the

same

file

name.

The

DOPEN

commandisavailable

onlytoBASIC

4.0

users.

When

used

with

eithera4040

or

8050,

DOPEN

maybeusedtocreate

relative

filesorsequential

filesoffixed

length.

The

formatofDOPEN

is:

DOPEN#lfn,"fn",Ddr,Lrl (,0NUdn)

(.W)

i

Where:

Ifn,fn, anddr arethe

sameasdefined

for

OPEN.

Lrldefines the recordlength asequalto rl

ONUdn

specifies

the

device

number

equaltodn

(with

default

device

being

8)

W

maybespecifiedtomean

virite

mode.

IfWisnot

specified

for

sequential

files,

the

file will be openedtoread.

DOPEN

is not available for the standard 2040 or 3040. "- "

The

CLOSE

command

closesafile

openedbythe

OPEN

command.

Its

format

is:

CLOSE

Ifn

Where:

lfn=the

logical

file

number

ofa

file

openedbythe

OPEN

command.

Always

closeafile

after

working

with

it.

You

are

not

allowedtohave

more

than

ten

open

filesmthe

computer

and

fiveinthe

disk

drives,soitisprudenttomakeahabitofclosing

filesassoonaspossible.

This

way

you

will

always

have

the

maximum

numberoffiles

avail

able

for

use.

DOLOSE

The DOLOSE command is available only to BASIC 4.0 users. This command closes files

opened

with

the

DOPEN

command.

The

format

of DOLOSE is; It

DCLOSE#Ifn

-yf

Where:

lfn=the

logical file

numberofthe

filetobe closed.

The

DOLOSE

command

may

alsobeused in

this

format:

DOLOSE

ONUdn

Where:

dn=the

device

number of the disk unit (defaults to 8).

When

used

in this

form,

DOLOSE

command

closes

all

active

disk

files

on the

specified

unit.

The following examples illustrate some applications of DOLOSEcommand:

Example

1: DOLOSE

Close all files currently OPEN.

Example

2:

DOLOSE#5

Close only logical file 5.

CLOSING

THE

COMMAND

CHANNEL

Closingthe command channel closes all channels associated with the disk drive. No other

partof the

logical

file

environment is affected. Thatis,the computer

does

not

recognize

that

the

files

have

been

closed.

The

following

example

illustrates

asituation in

which

several

channels

are

closed

down

bya

single

CLOSE

command.

Example:

OPENl.8.15

OPEHC-!.S.2..0:FILE1.SEG..WRITE"
0PEN4.8.5."G:FILE2.SEQ.WRITE"

PRINT#:::..

"IMPORTRHT

DflTR"

PRIHT#4.."Ni:iRE

DftTfi"

OPENS,4

?FILE

OPEN

ERROR?

REFinV.

The command channel is opened.
Data Channels are opened for writing.

A channel is opened

to

the

printer by

mistake.

An

error

message is displayed on

the

screen.

Since

there

was

an error, all

logical

files

in the computerare closed, but the channels in the

diskdriveare still open. To closethe disk channels,type:

V " -

OPENI.8,15

CLOSEl

Nowall data channelsin the diskdriveare properly closed.

CLOSING

THE

DATA

CHANNEL

"Hie

CLOSE

command

closesafile

and

the

dataorcommand

channel

assoc^jated

with

it.

Whenever

you

closeafile

opened

witha

write

channel,

the

closing

of that

file

writes

the

final

block

ofdatato the

disk

and

updates

the

disk

directory.

When

you

closeafile

opened

with a read channel, that channel is simply closed down.

NOTE:

Wheiiadriveisinitialized

with

INITIALIZE,

NEW,

DUPLICATE,orVALIDATE,

all

channels

associate

with

that

drive

are

deleted.

These

commands

should

notbeexecuted

when

thereare any

files

opensincethe

files

will'b6

disrupted.

PRINT#

The PRINT#command transmitsa diskcommand stringto the

drive.

The

formatofPRINT#

is:

PRINT#fn,"commandstring"

Where:

•

lfn«a

file

previously

opened

using

secondary

address

15

tf yy:

i'

''commandstring'-disk handling or diskfile

handling

commands.

These

disk

commands

''

are discussed in detail in Chapter 3 of this manual. '

•; ; r J;,'

'v;:

PRINT#

may

alsobeusedtotransmit

datato a

previously-opened

sequentialorrelative

file.

A

semicolon

mustbeused

asa

terminator

for

each

PRINT#

statement

when

using

BASIC

3.0 to avoidsendingextraneous line feedsto the diskette. Thesecharactersare written to

the

diskette

bythe

BASIC

PRINT#

routine

aspartofthedata

terminator.

It is

important

to

be

aware

ofthis

face

because

the

carriage

return

aloneisseen

asa

terminator

bythe

DOS.

Hie

line

feedisthen

stored

inthe

fileasthe

first

characterinthe

next

record.Toavoid

this,

use

the

following format:

•KxMi^e:7:Kmri^,''k)NESABC'';Cini$a3);

'

The

CHR$(13)

isthe

carriage

return

nectary

forthe

proper

termination ofthe

record

on

the disk.

When

thisrecordisinput, the result

willbeJONESABC

which

isthe

desired

result.

BASIC

4.0

users

do not

needtofollow

this

procedure

(though no

harmful

ieffects

will

result

firom

it). In

BASIC

4.0,any fileopenedwithIfn

less

than 128

will

automatically suppress

the

line

feed.

The following format may then be used:

PRINT#lfn,A$ -

This

will

produce

the

desired

value

of A$for the

record,

and

will

notinterfere withthe next

record.

41

Several variables

may

be writtentothe

disk at

the

same time.

.

-V

The

format:

PRINT#lfn,A$,B$,C$

will

resultin a

single

variable

(A$+B$+C$)

being

retrieved by the input command.

The

format:

i ,

••

v."!

•;

z . ^ .

PRINT#lfn,A$CHR$(13)B$CHR$(13)C$

will

result

inthe

variables

A$,

B$,

andC$being

separatedbycarriage

returns,

and

they

may

then be input as separatevariables. ' i ' ; ; r

The

I^UT#

commandisusedtotransfer

information

fromanIEEE

device

suchasthe

disk

drive

into

computer

memory.

INPUT#isvalid

only

when

used,

ina

program

and

onl>^when

referencing a logical file

that

has been OPENedfor input.

The

format

for

INPUT#

is:

•'

INPUT#lfn,A$

or

INPUT#lfn,A

'---v:-

Where:

lfn=afile previously opened

using

secondaryaddress 15 '

A$=astringvariable

which

will

conts^

the

data

transferred.

-^ '

A'^anumeric variable which willcontain the data transferred. * ,

INPUT#mayalsobe usedto transfer

several

strings of data at one time: ' '•

V

INPUT#lfn,A$,B$,C$ ^ ' ;" ' ^

• ^

•••--;••' • i• ^.j . - ./ '

Where:

A$, B$, C$ willcontain the data transferred from the disk. '

^'

v-'-

u-

In

this

format,

the

data

strings

must

have

been

separatedbycarriage

returns

(CHR$(13))

at

the

time

they

were

writtentothe

diskinordertobe

retrieved

separately.Nosingle

string

may

contain

more

than80charactersifitisto

be INPUT. ^

>;

sir?:;

•

Example

1:

^

.v?-;-'V

• •

•.5^

2blNPUT#2,A^^^^^^^

l

:•

'

' Input the nextdataitem

which

mustbein

numeric

form

and

«««£"

the

value

•

to

variable

A.

. - :

,v?sr

\ ^^ ;

^ .. _ ^ ,

Example

2:

.

•/

'•

' . • ' • - ' ' • • •

10INPUT#8,A$

Input

the

next

data

itemasa

string

and

assignitto

variable

A$.''^^

^

' • ' • '

'--K::-"

• -'i

'fh

Example

3;

^Uv •:

• ..;.V.1^7:iC'.'.

••;

•'J-:

:0>

.•'

••

60 INPUT#?,B,C$

•• '

V'!

^ i'

.^•'•

'CO;>•;,:i

;.

Input

the

next

two

data

items

and

assign

the

firsttonumeric

variableBand

the secondto stringvariable C$. j .

For

strings

longer

than80characters,

the

GET#

command

mustbeused.

=.

The

GET#

commandisusedtotransfer

individual

bytesofinformation

fromanIEEE

device

suchasthe

disk

drive

into

computer

memory.

GET#isvalid

only

when

usedina

pro

gram

and only whenreferencing afile that hasbeen

OPENed.

vjTie^matof

GET#'is:"

- '

g3;G^n.A$-i4; ^ ^

oW

u

....

GET#

Where:

v^fn-a

file

previously

opened

using

secondary

address

15

... '

A$=a

string

variable

which

will

contain

the

data

transferred.

. '

GET#

may

alsobeusedtotransfer

several

bytesofinformation,

whichisuseful

for

retriev

ing

strings

which

have

been

writtentothe

diskina

format

whichisunacceptable

for

the

INPUT

command

(strings

longer

than80characters).

:'lFor'example:klOAA$=""-S

20

FOR

1=1TO254

. ' 30GET#lfn,A$ ;

40

AA$=AA$+A$

L'

50NEXT < .

?•

^

resultina"

^ringoflength

254

being

ix^f^erred

from

the

disk^ogical

file

number

Ifn)

tothe

computer

memory

and

stored

inthe

variable

AA$

•••

"

trnMi""'""

Tliell^

used

piic^ioaPRIITO^INPUT#,

:

tion

the

file

pointertothe

desired

record

(and

byte)ofa

relative

file.

For

example,ifrecord

pomterisret

beyond

the

last

record

and

PRINT#isused,

the

appropriate

numberofrecords

are

geni^tedtoexpand

the

filetothe^esired

recordviv^v;-;:

^^^^

< ...

RECORD#isavailable

onlytousers

iequipped

wtli

isASIC

4.0;

The

format

is:

I^CORD#ifn,r,b

. v, ^

Where:

lfn=a

logical

file

number

ofa

file

previously

opened

with

the

DOPEN

command

r=the

desired

record

number.4maybeeitheravariable

nameorvalue,

how

ever

if r isa

variable

name,

it must

appear

enclosedinparentheses.

0<=r<=65535

b=the

byte

position

desired

within

the

record.

Byte

positioningisoptional.

l<=b<=254

43

The

following

example

illustrates how

RECORD

commandisused

with

INPUT#:

Example:10RECORD#!,120

• H

Using

the

RECORD

commandtoselect

the

record.

20INPUT#1,A$

Input the next data itemasa string and

assign

it to

variable

A$.

A

detailed

exampleofthe

usageofthe

RECORD

command

for

relative

file

manipulation

is

foundinChapter

6.

QUICKLOAD

FEATURE

(BASIC 4.0)

This

command

featureisvalid

with

DOS2and

BASIC

4.0,

and

eithera4040or8050.

(This

command

will

also

function

properly

with

aretrofitted

2040.)

•^is

command

loads

the

first

fileonthe

diskindrive0into

memory.Toensure

thatthe

first

program

on the diskette is

accessed,

the

command

mustbethe firstdisk

command

given

afteracold

start.

STEP1: Turn the computer OFF, then ON.

STEP2:Make

surethe diskcontaining a

program

asthe first

file

isin

drive

0 and that the

drive

doorisclosed.

STEP3:Simultaneously

press

the

SHIFT

and

RUN/STOP

keys.

The

computer

will

initialize

the

diskindrive0,search

for

the

first

programonthat

disk,

and

load

it.

When

using

thisfeature the computer

will

automatically execute the

DLOAD

and

RUN

commands

and

it is

not

necessary to

enter

either

command.

•

-v'f.

,4

fr'.

•i :'f'",':

• r > •

MOVING

A

TAPE

PROGRAM

TO

DISK

Tliis

example

illustrates a

session

with

the computer, a tape

cassette

anda

disk

drive.

The

purpose isto copy a cassette

program

to a diskette.The

program

isthen readfrom the

diskettetothe

computer's

memory

and

printed.Itis

assumed

that

the

BASIC

program

was

previously

storedonthe

cassette.

Example:

Load the file from the cassette tape to the

computer's

memory.

Createa

program

file

containing the

program

on

diskette.

Eraseeverythingfrom memory. (The

NEW

command in BASICwillclear memory; the

NEW

diskcommand

will

format a disk.)

Load

the

program back into the computer's

memory.

Run the program to verify it has been loaded.

NOTES

46

i/^N

Chapter

5

ADVANCED

DISK

PROGRAMMING

This

chapter

provides

detailed

information

about

DOS

structure

and

disk

utility

commands.

The

utility

commands

provide

the

programmer

with

low-level

functions

that

maybeused

for

special

applications

suchasspecial

disk

handling

routines

and

random

access

techniques.

COMMODORE

DISK

OPERATING

SYSTEM

(DOS)

l^e

DOS

file

interface

controllerisresponsible

for

managing

all

information

between

the

disk

controller

and

the

IEEE-488

bus.

Most

disk

I/Oisperformedona

pipelined

basis,

re

sultingin a faster response to a requested operation.

The

file

systemisorganizedbychannels

which

are

opened

with

the

BASIC

OPEN

state-

^

ment.

When

executed

with

the

OPEN

statement,

the

DOS

assignsaworkspacetoeach

channel

and

allocates

either

oneortwo

disk

I/O

buffer

areas.Ifeither

the

workspaceorthe

buffer

isnot

available,aNO

CHANNEL

errorisgenerated.

The

DOS

also

uses

the

channel

structure to searchthe directory,and to delete and copy files.

The

common

memory

between

the

disk

controller

and

the

file

interface

controllerisused

as

256-byte

buffer

areas.

Three

ofthe

sixteen

buffers

are

used

bythe

DOS

forthe

Block

Availability

Maps

(BAM),

variable

space,

command

channel

I/O,

and

disk

controller's

job

queue.

•^e

job

queue

isthe

vital

link

between

the

two

controllers.

Jobs

are

initiated

onthe

file

sidebyproviding

the

disk

controller

with

sector

header

and

typeofoperation

information.

The

disk

controller

seeks

the

optimum

jobandattempts execution.Anerror

condition

is

then

returnedinplaceofthe

job

command.

Ifthe

jobisunsuccessful,

the

file

side

re-enters

the

jobagiven

numberoftimes,

depending

upon

the

operation,

before

generatinganerror

message.

The

secondary

address

given

inthe

OPEN

statementisusedbyDOSasthe

channel

number.

The

number

the

user

assigns

to a

channelisonlyareference

number

thatis

usedtoaccess

the

work

areas,

andisnot

related

to the

DOS

orderingofchannels.

The

LOAD

snd

SAVE

statements

transmit

secondary

addresses

of0

and1,respectively.

The

DOS

automatically

47

48

interprets

these

secondary

addressesasLOAD

and

SAVE

functions.

Unless

these

functions

are

desired

when

opening

files,

avoid

secondary

addressesof0

and1.The

remaining

num

bers,2through

14,

maybeusedassecondary

addressestoopenupto

five

channels

for

data.

DISK UTILITY COMMAND

SET

The

disk

utility

command

set

consists

ofthe

following

commands:

Commands

Abbreviations

General

Format

BLOCK-READ

B-R

"B-R:»ch,dr,t,s

BLOCK-WRITE

B-W

"B-W:"ch,dr,t,s

BLOCK-EXECUTE

B-E

"B-E:"ch,dr,t,s

BUFFER-POINTER

B-P

"B-P:»ch,p

BLOCK-ALLOCATE

B-A

"B-A:"dr,t,s

BLOCK-FREE

B-F

"B-F:"dr,t,s

memory-write

M-W

"M-W*

'adl/adh/nc/data

memory-read

M-R

"M.R"adl/adh

memory-execute

M-E

"M-E"adl/adh

USER

U

"Ui:parms"

Where:

ch-the

channel

numberinDOS:

identicaltothe

secondary

addressinthe

associated OPEN

statement.

dr=the drive number: 0 or 1

®

number,

the

sector

ranges

for

the

2040,

3040,4040,

and

8050

are

showninAppendix

C.

pointerposition for the bufferpointer.

adl=the low byte of the address*.

adh=the high byte of the address*.

nc=the

numberofcharacters:1through

34*.

data=the

actual

datainhexidecimal.

Thisistransmittedbyusing

the

CHR$

function,

i.e.

CHR$(1)

would

send

the

binary

equivalentofhexidecimal

ui,

(decimal

1).

i=the index to

the

User Table.

parms=the

paramc^ers

associated

with

theUcommand

(optional).

f

The

values

usedinconjunction

with

the

memory

commands

existinthe

2040,

3040,

and

4040ashexidecimal

values

and

mustbetransmittedasCHR$(n),

wherenis

the

decimal

equivalentofthe

desired hexidecimal value.

NOTE;Ifusing

variables

the

format

must

have

only

the

commandinquotes.

For

example:

"B-R:"ch,dr,t,s correct
"B-R:ch,dr,t,s" incorrect

To

avoid

confusion,

itis

good

practicetouse

this

format

when

using

variablesorconstants.

As

implied

in the

preceding

format, these

commands

maybe

abbreviated

to the first

charac

terof

each

of the key

words.

Abbreviations

onlyare

accepted

forthose

commands

shown

in

lower

case.

The

parameters

associated

with

each

command

are

searched

for

starting

ata

colon

(:),orin

the

fourth

character

position

ifa

colonisnot

present.

The

example

follow

ing

shows

four

ways

thatthe

same

block-read

command

maybegiven.

NOTE:Ifusing

a 4040

initialize

the

disk

before

the

buffer

readorwrite.

Examples:

"BLOCK-READ:

"2,1,4,0

"B-R"2,1,4,0

"B.R"2;1;4;0

"B-READ:"2;1;4;0

Parameters

following

the

key

words

within

quotation

marks

maybeseparatedbyany

com

bination of the following characters:

Character

Name

Keyboard

Representation

Skip <cursor right>

Space Space bar

Comma

The

useofthese

characters

permits

sending

both

ASCII

strings

and

integers.

Parameters

not

within

the

confinesofquotation

marks

shouldbeseparatedbysemi

colons

(;).

Inthe

following

discussions,aPRINT#isassumedinall

examples.

BLOCK-READ

T^is

diskette

utility

command

provides

direct

accesstoany

blockona

disketteineither

disk

drive.

Usedinconjunction

with

other

block

commands,arandom

access

file

system

maybecreated

through

BASIC.

This

command

finds

the

character

pointerinthe

0-position

of

the

block.

Whenacharacterinthis

positionisaccessed

with

GET#orINPUT#,anEnd-

or-Identify

(EOI)issent.

This

terminatesanINPUT#

and

sets

the

Status

Word

(ST)to64

in

the

computer.

49

The

format

"B-R:"ch;dr;t;sisillustratedinthe

following

example.

Example; "B-R:"5;l;18;0

Reads

the

block

from

drive1,track

18,

sector0into

channel5buffer

area.

After

using

READtotransfer

the

datatothe

buffer,

the

data

maybetransferred

to

SToK

aS)

"""

TheU1command

described

under

USERissimilartothe

BLOCK-READ

command.

BLOCK-WRITE

men

this

commandisinitiated,

the

current

buffer

pointerisusedasthe

last

character

? l'"j-

I®

t''®

new

The

buffetisthen

writtentothe

mdicated

blockonthe

diskette

and

the

buffer

pointerisleftinposition

1.

The

format

B-W:

"ch;dr;t;sisillustratedinthe

following

example.

Example:

"B-W:"7;0;35;10

Writes

channel7buffertothe

blockondrive0,track

35,

sector

10:

s'sfable

with

DOS2.This

includes

the

4040

and

all

2040/3040

retrofits.

The

BLOCK-WRITE

commandisreplacedbytheU2command

for

the

4040.

BLOCK-EXECUTE

designed

routines to

reside

on diskand be

In

w,™r f ""•

^-EisreallyaB-R

withanaddition.

The

FUe

fcterface

Controller

begins

executionofthe

contents

after

the

blockisread

intoabuffer

^Mution

mustbeterminated

withareturn

from

the

subroutine

(RTS)

instruction.

Future

system

extensionsoruser-created

functions

may

implement

this

command.

The

format

B-E:

"ch;dr;t;sisillustratedinthe

following

example.

Example:

"B-E:"6;l;l;10

Readsablock

from

drive1,track1,sector10into

channel6buffer

and

exe

cutesItscontents

begmnmg

at position0 in the buffet:

BUFFER-POINTER

""e

P?'n'e'

associated

with

the

given

channel

toa

new

value.

Thfe

is

useful

when

acceding

particular

fieldsofa

recordina

block

or,ifthe

blockisdivided

into

records,

individual

records

maybeset

for

transmittingorreceiWng

datr

The

format

B-P;"ch,pisillustratedinthe

following

example.

Example: "B-P;"2;l

buffer*^"""®'^""e

beginningofthe

data

areainthe

direct

access

50

f

o

BLOCK-ALLOCATE

The

appropriate

BAMisupdated

inthe

DOS

memorytoreflect

the

indicated

block

as

allocated

(used).Infuture

operations,

the

DOS

skips

over

the

allocated

block

when

saving

programsorwriting

sequential

files.

The

updated

BAMiswrittentodiskette

upon

the

closure

of a write

file

or the

closure

of a direct

access

channel. X

Ifthe

block

requested

has

been

previously

allocated,

the

error

channel

indicates

the

next

available

block

(increasmg

track

and

sector

numbers)

withaNO

BLOCK

error.Ifthere

are

no

blocks

available

that

are

greaterinnumber

than

the

one

requested,

zeroes

are

displayed

as track

and

sector parameters.

The format "B-A:"dr;t;s isillustrated inthe

following

example.

Example: "B-A:"l;10;0

Requests

that

block

(sector)

0of

track

10be

flaggedasallocated

onthe

diskette

in

drive

1.

NOTE:

The

error

channel

should

alwaysbecheck

when

using

BLOCK

ALLOCATE,sothat

if

the

blockisalready

allocated,itwill

notbeoverwritten.Ifthe

blockisallocated,

the

error

message will also indicate

the

next

available block.

Example:

INPUT#15,EN,EM$,ET,ES

Reads

the

next

track

and

sector,

respectively,

intoETand

ES,

assuming

that

lfn=15

hasbeen

previously

OPENed

to thediskerrorchannel.

MEMORY

All

three

MEMORY

commands

are

byte-oriented

sothatthe

user

may

utilize

machine

language

programs.

BASIC

statements

maybeusedtoaccess

information

through

the

MEMORY

commandsbyusing

the

CHR$

function.

The

system

accepts

only

M-R,

M-W,

and

^

M-E:

neither

verbose

spelling

orthe

useofthe

colon

(:)is

permitted.

Memory-Write

This

command

provides

direct

accesstothe

DOS

memory.

Special

routines

maybedown

loadedtothe

disk

drive

through

this

command

and

then

executed

using

the

MEMORY-

EXECUTE

commandoroneofthe

USER

(U)

commands.Upto34bytes

maybedeposited

with

each

useofthe

command.

The

low

byteofthe

address

must

precede

the

high

byte

of

the

address.

The

format

"M-W:

"adl/adh/nc/dataisillustratedinthe

following

example.

Example:

"M-W:"CHR$(00)CHR$(18)CHR$(4)CHR$(32)CHR$(0)CHR$(17)CHR$(96)

Writes

fourbytesto

buffer2($1200ordecimal

4608):

51

Memory-Read O

The

byte

pointedtoby

the

address in

the

command

string

may

be accessed

with

this

com

mand.

Variables

from

the

DOSorthe

contentsofthe

buffers

may

also be

read

with

this

command.

The

M-R

command

changes

the

contentsofthe

error

channel

sinceitis used

for

transmitting

informationtothe

computer.

The

next

GET#

from

the

error

channel

(secondary address

15)

transmits

the

byte.

An

INPUT#

should

notbeexecuted

from

the

error

channel

afteraMEMORY-READ

command

untilaDOS

command

other

than

one

of

the

MEMORY

commandsisexecuted.

The

format

"M-R:

"adl/adhisillustratedinthe

following

example.

Example:

"M-R"CHR$(128);CHR$(0)

Accesses

the

byte located at ($0080 or decimal 128):

Memory-Execute

Subroutinesinthe

DOS

memory

maybeexecuted

with

this

command.

To

returntothe

DOS,

terminate

the

subroutine

with

RTS

($60).

The

format

"M-E:

"adl/adh

is illustrated in

the

following example.

Example:

"M-E"CHR$(128);CHR$(49)

Requests

the

executionofcode

beginningat$3180.

USER

This command provides a link to

6502

machine

code

accordingtoa

jump

table pointed

to

by

the

special

USER

pointer.

RefertoTable5.The

second

characterinthis

command

is

used as an

indextothe

table.

The

ASCII character 0

through

9 or A

through0may

be used.

Zero sets

the

USER

pointertoa

standard

jump

table

that

contains

linkstospecial

routines.

The special USER commands U1 (or UA) and U2 (or UB) can be used to replace the

BLOCK-READ

and

the

BLOCK-WRITE

commands.

The

format

of

U1

is:

"Ul:"ch;dr;t;s

U1 forces

the

character

count

(buffer

pointer)to255

and

reads an

entire

block

into

memory.

This

allows

complete

accesstoall

bytesinthe

block.

The

format

of

U2

is:

"U2:"ch;dr;t;s

U2

writesabuffertoa

blockonthe

disk

without

changing

the

contentsofposition

0 as

B-Wdoes.

This

is useful

whenablockistobereadin(with

B-R)

and

updated

(B-Ptothe

field

and

PRINT#),

then

written

back

to diskette with U2.

Refer

to

the

random

access example in Chapter 6 for an application of

theU1and

U2

commands.

52

^

^0^

Table 5.

Standard

Jump

Table

USER

DESIGNATION

ALTERNATE

USER

DESIGNATION

FUNCTION

Ul

UA

BLOCK-READ

replacement

U2

UB

BLOCK-WRITE

replacement

2040/3040

4040

8050

U3

UC

jump

to

$1300

$1300

$1300

U4

UD

jump

to

$1303

$1303

$1303

U5

UE

jump

to

$1306

$1306

$1306

U6

UP

jump

to

$D008

$1309

$1309

U7

UG

jump

to

$DOOB

$130C

$130C

U8

UH

jump

to

$DOOE

$130F

$130F

U9

UI

jump

to

$D0D5

$10F0

$10F0

U:

UJ

powerupvector

U3thru U9commands are user-defined. The locationsjumpedto are locatedin the buffer

areasofRAM

and

routines

maybewritten to

reside

thereand

downloaded

using

the

M-W

command.

Locations

D008,

DOOB,

DOOE,

and

D0D5

are

located

inthe

expansion

ROM

slot

in the 2040/3040and

USER

commands

maybe

usedtoaccessaROMorEPROM

locatedin

that position. Location

lOFO

isthe locationof the

NMI

vectorin the 4040 and8050.

53

54

Table6.Block

Distribution By

Track

2040,

3040

Track

number

Block

or

Sector Range

Total

Ito

17

18to24

25to30

31to35

Oto

20

Oto

19

Oto

17

Oto

16

21
20

18
17

4040

Track

number

Block

or

Sector Range

Total

Ito

17

18to24

25to30

31to35

Oto

20

0to18

Oto

17

Oto

16

21
19

18

17

8050

Track

number

Block

or

Sector Range

Total

Ito

39

40to53

54to64

65to77

Oto

28

Oto

26

Oto

24

Oto

22

29

27

25

23

^The

T&S.

provided

JlAY

tSoS""'" "inWing

information

obtained

using

tlie

DIS-

I

Table 7. 2040,

3040

BAM FORMAT

Track

18,

Se

ctor

0.

BYTE

CONTENTS

DEFINITION

0,1

2

3

4-143

18,01

1

0

Trackand sectorof firstdirectory block.

Indicates version 1

format.

Null

flag

for

future

DOS

use.

♦Bit

mapof

available

blocksfor tracks1-35.

*l=available

block

O=block

not

available

(eachbit represents one block)

Track

18,

Sec

;tor

0.

BYTE

CONTENTS

DEFINITION

144-161

Disk

name

padded

withshifted

spaces.

162-163

Disk

ID.

164-170

160

Shifted

spaces.

171-255

0

Nulls,

not

used.

Note:

ASCII

characters

may

appearinlocations

180

thru

191onsome

diskettes.

55

Table9.4040

BAM

FORMAT

Track

18,

Sector

0.

BYTE

CONTENTS

DEFINITION

0,1

18,01

Track

and

sectoroffirst

directory

block.

2

65

ASCII

characterAindicating

4040

format.

3

0

Null

flag

for

future

DOS

use.

4-143

Bit

mapofavailable

blocks

for

tracks

1-35.

*l=avaaable

block

O=block

not

available

(each

bit

represents

one

block)

Table

10.4040

DIRECTORY

HEADER

Track

18,

Sector

0.

BYTE

CONTENTS

DEFINITION

144-161

Disk

name

padded

with

shifted

spaces.

162-163

Disk

ID.

164

160

Shifted

space.

165,166

50,65

ASCII

representation

for2AwhichisDOS

version

and

format

type.

166-167

160

Shifted

spaces.

171-255

0

Nulls,

not

used.

Note: ASCII characters may appear in locations

180

thru

191 on some diskettes.

o

Table

11.

8050

DIRECTORY

HEADER

BLOCK

Track

39,

Se

'ctor

0.

BYTE

CONTENTS

DEFINITION

0,1

38,0

Trackand sector of first

BAM

block.

2

67

ASCII

characterCindicating

8050

format

3

0

Null flag for future DOS use.

4,5

0

Unused.

6-21

Disk

name

padded

with

shifted

spaces.

22,23

160

Shifted

spaces.

24,25

Disk

ID.

26

160

Shifted

space.

27,28

50,67

formaVl^pf

version

and

29-32

160

Shifted spaces.

33-255

0

Nulls,

not

used.

57

58

Table

12.

8050

BAM

FORMAT

First

BAM

block:

Twck

38,

Sector

0.

BYTE

CONTENTS

definition

Track

and

sectorofsecond

BAM

block

ASCII

characterCindicating

8050

format.

Null

flag

for

future

DOS

owest

track

number

representedinthis

BAM

Highest

track

number+1in

this

BAM

block.

Numberofblocks

unusedontrack

1

Bit

map

representationofavailable

blocks

on

track

1.

11-255

_BAM

for

tracks

2-50,5bytes

per

track

Second

BAM

block:

Track

38.

Sector

3

BYTE

CONTENTS

definition

Track

and

sectoroffirst

directory

block

ASCII

characterCindicating

8050

format.

Null

flag

for

future

DOS

use

track

number

represented

this

BAM

block.

Highest

track

number+1in

this

BAM

block.

Numberofblocks

unusedontrack

51

Bit

map

representationofavailable

blocks

11-140

*BAM

for

tracks

52-77,5bytes

per

track.

141-255

Unused.

♦STRUCTURE

OF

BAM

ENTRY

FORATRACK

BYTE

0

1

2

3
4

definition

for

track

Dit

map

sectors

0-7

bit map sectors

8-15

bit mapsectors16-23
bit map sectors 24-31

l=available

O=not available

on

track

51.

Note;

"BLOCKS

FREE"

may

appearinlocations

180

thru

191onsome

diskettes!

n

u

8050

DISK

ZONES

The

8050

disk

format

uses

a

variable

number

of

sectors

per

track

according

to

four

density

zones.

The

BAM

is

made

up

of

two

blocks

(see

BAM

structure

information).

The

first

block

represents tracks 1 thru 50 and the second, tracks 51 thru 77.

TRACK

NUMBER

OF

RANGE

SECTORS/TRACK

TOTAL

SECTORS

ZONE

BAM

AREA

1-39

29

1131

1 1

40-50

27

297

2

1

51-53

27

81

2 2

54-64

25

275

3 2

65-77

23

299

4

2

-

29

DIRECTORY

- 2

BAM

2052

BLOCKS

AVAILABLE

When

the

DOS

requires

access

to

a

BAM

block

not

currently

in

memory,

it

must

be

read

from

the

diskette.

Before

reading

in

the

other

block,

the

DOS

checks

to

see

if

changes

have

current block.If

changes

have

been

made,

the current blockiswritten to

the

diskette.

The

other

BAM

block

is

then

read

into

the

DOS

memory.

59

60

Table

13.

DIRECTORY

FORMAT

Track 18, Sector 1 for 4040

Track 39, Sector 1 for 8050

BYTE

definition

0,1

Track

and

sectorofnext

directory

block.

2-31

*File

entry

1

34-63

♦File

entry

2

66-95

*File

entry

3

98-127

!>

*File

entry

4

130-159

*File

entry

5

162-191

*File

entry

6

194-223

♦File

entry

7

226-255

*STPFTr^rr

TT>I?/-ira

*File

entry

8

BYTE

CONTENTS

DEFINITION

0

128+type

?YPEr

«'«•

1 - SEQential

2 =

PROGram

3 =

USER

4 =

RELative

1,2

Track

and

sector

of1stdata

block.

3-18

File

name

padded

with

shifted

spaces.

19,20

block!™

sector

21

Relative

fileonly:

Record

size.

22-25

Unused.

26,27

file when OPEN®is in

28,29

Numberofblocksinfile:

low

byte,

high

byte.

n

rs.

Table

14.

SEQUENTIAL

FORMAT

BYTE

DEFINITION

0,1

Track and sector of next sequential data block.

2-256

254 bytesof data with

carriage

returnsasrecord terminators.

Table

15.

PROGRAM

PILE

FORMAT

BYTE

DEFINITION

0,1

Track and sector of next block in program file.

2-256

254

bytesofprogram

info

storedinCBM

memory

format

(with

key

words

tokenized).End of fileismarkedby three zero bytes.

61

62

SYNC

TRACK

SECTOR

CHECK

SUM

SECTOR

GAP!

SYNC

Index

Hole

NOTE;
Nottoscale

POINTERS TO LINK

TOGETHER ALL BLOCKS

254

BYTES

OF

DATA

CHECK

SUM

Figure42040,3040,4040

Format:

Expanded

Viewofa

Single

Sector

&ifii"nr:S

for

the

2040.

characters.

Blocks

within

the

same

file

are

linlrpH

f «

consistingof256

stored

block

pointer.

By

point

"nrtrthelocatio^

iff

hf

TT

systemtoretrieve

data

from

non-contieuous

bIork«*R

f ^

pointers

enable

the

file

triggersasearch

forTn^ZwhSf

a

related

blocks

until

the

entire

filpicjieeamki

j J j

utilizes

block

pointerstolocate

SEQ.

and

USRZutmzeThis

fo™^

A"

PRO,

35

tracks

(or

rings)

of

sectors

per

track

will

vary

(as

illustratedinTaMsRt^ f

numbered1to

77.

The

number

ference

and

recording

fre^ncy

differencesintrack

circum-

Jnd%rdirectJrThVa"r^1d"

and

occupied

storage

locationsondiskette

The

l^t

128

bvfcP^T*'®^

*

monitors

avaUable

L

^3^

SECTOR

o

Index
Hole

POINTERS

TO

LINK

TOGETHER

ALL

BLOCKS

WITHINAFILE

NOTE:

Nottoscale

\

o

SYNC

08

IDl

ID2

TRACK

SECTOR

CHECK-

SUM

GAPl

SYNC

07

n

254

BYTES

OF

DATA

CHECK

SUM

GAP

2

Figure

5—

8050

Format:

Expanded

View

ofa

Single

Sector

Figure5illustratesanexpanded

viewofa

single

sectorona

diskette

formatted

for

the

8050.

In

additiontoother

information,

each

sector

containsadata

block

consistingof256

stored

characters.

Blocks

within

the

same

file

are

linked

togetherbymeans

ofa

two

character

block

pointer.Bypointingtothe

locationofthe

next

data

block,

block

pointers

enable

the

systemtoretrieve

data

from

non-contiguous

blocks.

Retrieving

the

first

data

block

within

a

file

triggersasearch

for

the

next

data

block

which,inturn,

utilizes

block

pointerstolocate

r^^ed

blocks

until

the

entire

fileisassembled

and

made

available

for

display.

All

PRG

SEQ, and USR files utilize this format. *

A

data

blockisaddressedbytrack

and

sector.A2040

diskette

contains35tracks

(or

rings)

numbered

1to35whilean8050

diskette

contains77tracks

numbered

1to

77.

The

number

of

sectors

per

track

will

vary

(as

illustratedinTable6)duetodifferencesintrack

circum-

ference and recording frequency.

The

80M

maintains

system

filesontracks38and39wliich

contain

the

BAM,

diskette

name,

ID,

and

file

directory.

The

BAM,

residentinthe

first

255

bytesofsectors0and

3of

toack

dS,

monitors

available

and

occupied

storage

locationsondiskette.

The

file

directory

header

bkMk,

beginningonsector

0of

track

39,

contains

the

diskette

name

andIDwithin

the

first30bytes.

63

f9

S310N

J

i.

Chapter

6

ADVANCED

FILE

HANDLING

In

the

preceding

chapters,

you

learned

howtomanipulate

filesonthe

disk,

and

were

shown

the

formatofcommands

usedtocreate

and

update

files.Inthis

chapter,

you

will

utilize

theseskillsin a file handlingapplicationusingrandom or relative

access.

SPECIAL

OPEN

AND

CLOSE

STATEMENTS

FOR

DIRECT

ACCESS

The

BASIC

statements(after initializing the disk):

OPEN2,8,4,"#»

or

OPEN2,8,4,"#12"

H

openachanneltoone

buffer,tobe

used

with

the

block

commands.Inthe

first

example,

the

first

available

bufferisallocatedtochannel4,The

second

exampleisan

attempttoallo

cate

buffer

12 to the

channel.

Ifthe

buffers

arenot

available,aNO

CHANNELS

errorcon

dition isgenerated. The explicit buffer allocation can be used to reservea buffer for

position dependent code as in

the

case of an EXECUTE command.

ExecuteaGET#

statementtofind

the

number

ofthe

allocated

buffer.

The

byte

trans

mittedisthe

buffer

number.Abuffer

number

may

onlybeobtained

PRIORTOany

write

or read

operationstothat

buffer.

The

CLOSE

statement

clears

the

OPENed

channel andwrites the

BAM

to the diskettethat

was

last

used

bythat

channel.Toavoid

confusion,

limit

yourselftoaccessing

one

drive

with

any

direct

access

channel.

65

RANDOM

ACCESS

EXAMPLE

^

Since

the

BLOCK-ALLOCATE

command

returns

the

next

available

diskette

block

throuffh

t e

error

channel,itcanbeusedinthe

allocationofrecords.

This

feature

allows

creating

a

random

file

without

bemg

concerned

with

the

actual

physical

structureofthe

diskette

tessi's';-1'"

..

recordISstoredmablock,

anditis

necessarytomanage

end-of-record

pointersinBASIC

A

smaller

application

might

take

advantageofthe

B-R

and

B-W

commands.

1

'I"®

random

access

program

entitled

"Random

It

®f

"P°"

®

scheme

and

providSk

access

through

^IC

programming.

Mostofthe

programming

below

Une

2000

is

SlS;;tSdf

len-iustiffbinary

f^r^d

characte^telro?Sftric«^^^^^^

f"

''.T^ '

^paSwrh1Zt"-The^^^^^

fUename

DUPLICATE

mustbeperformed,

since

the

DOSisunabletoCOPY

without

a

To

Create

A

File

STEPl:

Insert

the

TEST/DEMO

diskindrive

0.

STEP2:^pe:

OPEN15,8.X5

and

press

RETURN

Opens

the

command

channel

and

initializes

the

diskette.

STEPS:

^pe:LOAD"0:R^OM1.00",8

and

press

RETURN

inis

command

loads

the

random

access

program.

66

STEP

4:

Insertablank

diskette

into

drive

1.

STEP5: Type; PRINT#15,"N1:MAIUNG LIST" and press

RETURN

STEP 6: Type: RUN and press RETURN

The

screen displays:

"DO

YOU WISH

TO

CREATEAFILE"?

STEP 7: Type: Y and press RETURN

The

screen

displays:

"RANDOM

FILE

NAME"?

STEP 8: Type

the

file name: PHONE LIST and press RETURN

The

screen displays:

"KEY

FILE

DRIVE

NUMBER"?

STEP 9: Type: 1 and press RETURN

The

screen displays:

"RANDOM

FILE

NUMBER"?

STEP

10:

Type: 1 and press RETURN

The

screen displays:

"ENTER

ID OF RANDOM

DISK"?

STEP

11:

Type: CS and press RETURN

The

screen displays:

"NUMBEROFRECORDS"?

STEP

12:

Type:

10

and press RETURN

For

this example,

ten

was entered since this is

the

MAXIMUMnumber of

records the file can contain. If lessrecords are needed, specify a number less

than

ten.

The

screen

displays:

"NUMBER

OF

FIELDS

PER

RECORD"?

STEP

13:

Type:

4

and

press

RETURN

Thisisthe

number

of

'items'

each

field

contains.

The screen displays: "INPUT FIELD

NAME,

FIELD SIZE, FIELD TYPE".

TYPES: 0=BINARY, 1=NUMERIC, 2=ALEHA

FIELD

1?"

enter:

NAME,20,2

and

press RETURN

FIELD

2?"

enter: PHONE,15,2 and press RETURN

FIELD

3?"

enter: ADDRESS,40,2 and press RETURN

FIELD

4?"

enter: COMMENTS,40,2 and press RETURN

To

Add

A

Record

STEP 1:

The

screen displays: "WHOSE RECORD DO YOU WISH TO SEE?

Press

RETURN.

The

screen displays:

«****aDD

RECORD****"

NAME"?

STEP 2: Type: COMMODORE and press RETURN

The

screen

displays:

"PHONE"?

67

STEP3:Type;

727-1130

and

press

RETURN

^

Thescreen displays: "ADDRESS"?

STEP4:TVpe:

3330

SCOTT

BLVD

SANTA

CLARA

OA.

95051

and

press

RETURN

The

screen

displays:

"COMMENTS"?

STEP5:TVpe:

MANUFACTURES

MICROCOMPUTERS

and

press

RETURN

ftillOTimN

record

do

you

WISH

TO

SEE'?

The

screen

displays:

"****ADD

RECORD****"

REtS

'I®®''®''nswe.

For

example:

smith

and

press

PHONE"?

Enter

the

phone

number:

999-356-1012

and

press

RETURN

^^P^rItURn"'"

GATOS

CA.

95030

^

PERJPH^

En'efacomment.

For

example:

MANUFACTURES

r^UiRIPHERALS

and pressRETURN

STEP

6:

"WHOSE

RECORD

DO YOU

WISH

TX)

SEE"?

The

screen

displays:

«****aDD

RECORD****"

®"'®'"'®''®®''^"ame.

For

example:

JONES

and

press

PHONE"?

Enter

the

phone

number:

999-268-1795

and

press

RETURN

^^SetuRn"'®'

SAN

JOSE

CA.

95117

cCSSS^'"

manufactures

To

See

A

Record

The

computer

displays:

"WHOSE

RECORD

DO

YOU

WISHTO<5PF'»?

Enter:

COMMODORE

and

press

RETURN

^

To

Change

A

Record

After

displaying

the

record,

the

screen

displays:

"ANY

MODS"?

STEPl:

Type:

YES

and

press

RETURN.

The

screen

displays:

"WHICH

FIELD"?

Enter

the

numberofthe

field

you

wishtochange.

68

STEP 2: Type: 4 and press RETURN.

The

computer

displays

that

field:

US

HEADQUARTERS

STEP

3:

Press

RETURN.

The screen display asks if there are; "ANY MODS".

STEP

4: If the

record

iscorrect, type:

NO

and

press

RETURN

Getting The Directory of Listings

The screen displays:

"WHOSE

RECORDDO YOU

WISH

TO SEE"?

Type: /DIR and press RETURN

The computer displays the directory.

Ending

The

Program

Thecomputerdisplays:

"WHOSE

RECORDDOYOU

WISH

TOSEE"?

Type:

//

and

press

RETURN.

The

program

ends.

RELATIVE FILES

4040,

8050

Direct

accessofrelative

files

isa

method

that

allows

the

programmertopositiontoany

record on the disk relativeto the beginning of that file. Comparethis method to the stan

dard procedure of

having

to searcheach track and sectorfor the

desired

informationand it

becomes

apparent

that

sucharelative

handling

method

would

result

ina

great

reduction in

the amount of time required to finda specific record stored on disk.Thisreduction in the

amount of time required to locateand fetch a file through the applicationof relative file

handling

techniques

frees

the

user

from

the

major

objectiontousing

sequential

disk

files:

excessive

"look

up"

time.

Both

DOS2and

2.5

(4040

and

8050)

are

capableofhandling

relative

files

and

should

signi

ficantly

reduce

the amountof timespent retrieving disk

files.

The two maincomponentsof a relative filearethe sidesector chainof blocksand the data

blockchain. Bothare

linked

togetherthrough

forward

pointers

similar

to those

used

ina

sequential

file.

Record

sizes,

while

fixedinlength,

may

range

from

oneto 254

bytes.

The

numberofrecordsislimited

to the

capacity

of the

disk

but for

practical

purposes

should

not

exceed

65,535.

Thesidesectorsdo not contain record information, but do contain locations of the data

blocks.The recordsizedictates wherethe pointer is placed when a record numberis refer

enced

because

the

record

sizeisused

inan

algorithmtocompute

where

the

pointer

is

placed

when

a recordnumberis

given

throughthe

RECORD

command. The sidesector

also

contains a table of pointers to all of the other sidesectors within the file. In order to move

from

one

side

sectortoanother,

the

pointerisreferenced

through

the

appropriate

DOS

command,

and

the

corresponding

side

track

and

sector

read

into

memory.Byusing

the

information

contained

inthe

referenced

side

sector,

thedata

block

pointer

canbelocated

and

used

to readin the actualdata blockcontaining the record.The

relative

filedata block

69

pointersinthe

side

sectors

aUow

the

DOStomove

from

one

recordtoanother

within

two

rfrid

Hafa"»6

requiredtofindade-

Sired

data

block

when

comparedtosequential

methods.

sectors

and

each

side

sector

may

contain

pointersto120

?«9

204

Dual

Drive

FloppySSins

182,880

bytes

(120

pomters/side

sector*6side

sectors*254

bytes/block)

which

hanno„c

tobegreater

than

the

total

storage

capacityofthat

particul^

dS ^

Table16.

RELATIVE

FILE

FORMAT

DATA

BLOCK

BYTE

0,1

2-256

SIDE SECTOR BI,OCK

BYTE

0,1

3

6,7

10,11

12,13

14,15

16-256

DEFINITION

Trackandsector of next data block.

254

bytesofdata.

Empty

records

containFF(all

binary

ftp

pnHifth

^ J

foUowedby00

(binaryaUzeros)

to

MIU

(Oof

PartiaUy

fiUed

records

are

padded

with

DEFINITION

Track

and

sectorofnext

side

sector

block.

Side

sector

number.

(0-5)

Record length.

Track

and

sectoroffirst

side

sector

(number

0)

Track

and

sectorofsecond

side

sector

(number

1)

Track

and

sectorofthird

side

sector

(number

2)

Track

and

sectoroffourth

side

sector

(number

3)

Track

and

sectoroffifth

side

sector

(number

4)

Track

and

sectorofsixth

side

sector

(number

5)

Track

and

sector

pointersto120

data

blocks.

tZanTaXK^^^^^^

generated

recorl,

from

the

pZS

current

enTof

t^f

uf

automatically

generated

bvthe

DOS

Thic

in i

record

number

will

be

necessary

toS^a

fil^r^Ldlel'^

^

"ocks

For

example,ifthe

current

sizeofthe

relatiie

recordisone

dataHtT*®

'J"®/diskette,

number

referenced

would

exnandittn1Qfi

hir^^h-

fu

data

block

long

and

the

record

70

Spellingisa

key

featureofrelative

files

which

aidsinreducing

the

numberofdisk

read/

?ISc

o

and

retrieve

data.

Before

explaming

how

this

feature

of

UUt>2and

2.5

improves

time

utilization

efficiency,weneedtoexamine

how

I/O

channels

are utilized by relative files:

^ena

channelisopenedtoa

previously

existing

file,

the

DOS

will

position

to

the

first

record

provided

that

the

given

parameters

match

properly.

The

record

u ^

necessaryonthe

OPENifthe

fileisalreadyinexistence,

but

the

DOS

causesachecktobe

made

against

the

record

size

that

was

originally

mdeinthe

DOPEN

statement

creating

the

file.Ifthesedonot

match,

then

error

50—record

not

present—will

be generated.

The

relative

channel

requures

three

memory

buffers

from

the

system,

whereas

sequential

files

only

require

two.

Since

there

are

twelve

channelsinthe

system

and

twoofthese

are

usedindirectory

searches

and

internal

functions,

only

three

relative

channels

canbeopenatone

time.

The

highest

numberofbuffers

that

can

be

usedisten,

which

limits

the

total

numberofchannels

which

canbeopen

at

any

one

time.

Ifarecord

was

foundtobeonthe

boundary

between

two

data

blocks,

that

is,

starting

in

one

data

block

and

finishinginanother,

then

the

DOS

would

read

the

first

segmentaswell

^

any

following

recordsinthe

second

data

block.Inpractice,

the

recordsofmost

relative

across

data

blocks.

The

only

exceptions

are

record

size

1,2,127,

and

^4.

Th^e

divide

evenly

into

the

254

sizeofthe

data

block

and

spanningisunnecessary.

This

methodofspanning

has

the

advantageofrequiringnosystem

memory

overhead

aside

from

that

required

forthe

side

sector

blocks

inthe

relative

files.

Whenarecordiswritten

upon

through

the

PRINT#

statement,

the

data

blockisnot

immediately

written

outItis

only

witten out

when

the

DOS

moves

beyond

the

particular

data

blockinwhich

that

record

resides.

This

can

occur

through

successive

printingtosequential

records,orwhen

positioning to another record outside of that particular block.

^causeofthe

spanning

feature,itis

recommended

that

two

channels

notbeopentoa

rela

tive

fUeatthe

same

timeifeither

channel

willbewritingtothe

same

file.Anupdate

may

be

madeinthe

channel's

particular

memory

buffer

area,

but

the

change

may

notbemade

on

disk

until

the

DOS

moves

that

particular

data

block.

Thereisno

restrictiononthis,

how

ever,

andincertain

instances

where

the

fileisonly

read

from,itmaybeadvantageous

to

have

more

thanone

channel

open

to a

single

relative

file.

'"'t

printingtoa

recordbydetecting

tlie

EOI

signal

wiiichisgenerated

witii

each

PRINT#

statement.Ifthe

PRINT

statement

goes

over

the

maximum

record

size,

error

51-record

overflow-willbegenerated.

Any

data

overflow

willbetruncated

to fit the

num-

berofcharacters

specifiedbythe

record

size

and

the

DOS

will

positiontothe

next

record

in

sequence.Ifthe

print

statement

contains

less

characters

than

the

record

size,

the

remaining

positions

within

that

record

willbefilled

with

nulls.

Consequently,

when

positioningtoa

record

for

input

the

EOI

signalisgenerated

from

the

DOStothe

computer

when

the

last

non-zeroistransmitted.

Should

the

programmer

desiretostore

binary

information,arecord

terminator

suchascarriage

return

will

havetobe

used

and

the

record

size

increasedbyone

charactertoaccommodate

the

terminator.

While

the

DOSisgenerating

new

data

blocks

for

relative

files,

the

requested

record

number

K

comparedtothe

numberofdata

blocks

leftonthe

diskette.Ifthe

resulting

number

of

data

blocksisgreater

than

whatisleftonthe

diskette,

then

error

52-file

too

large-is

generated. ®

71

CREATING A RELATIVE FILE

The

following

examples

apply

onlytothose

users

equipped

with

both

BASIC40and

DOS

2.Intermsofhardware,

this

meansa4000or8000

Series

PETorCBM

mustbeusedasthe

computer and a 4040 or 8050 for the disk drive.

Whenarelative

fileisopened

for

the

first

time,

the

file

shouldbeinitializedbythe

program

mertoaUow

for

faster

subsequent

access,

andtoassure

that

the

DOS

reserves

sufficient

spaceonthe

diskette

for

the

future

data.Asimple

programtoperform

such

initialization

is

illustrated

below:

HODOPEN#l,"FILEl",D0,L50

120

GOSUB

190

130 RECORD#1,100

140

GOSUB

190

150 PRINT#1,CHR$(255);

160

GOSUB

190

170

DCL0SE#1

180

END

190IFDS<20

THEN RETURN

200

PRINT DS$

210

IF DS=50 THEN RETURN

220

STOP

the

preceding

example,

line

110

createsafile

with

the

name

FILEl

andarecord

length

handling

subroutinetobe

executed.Itis

good

pro-

grammmg

practicetocheck

the

error

channel

after

each

disk-related

operation.

Line

130

posiUons

the

file

pointertorecord

number

100

which

does

not

yet

exist

The

3n»

raSn

^

^^rPret^

as

a

warmng

rather

thananerror

condition.

This

messageisnormally

expectedtooccurasa

f

'he

first

time

and

indicates

thatnoINPUT

or ur<r operation should beattempted.

Line

150

causes

record

number

100

(becauseofthe

pointer

positionedbyline

130)tobe

written.

During

this

write

operation,

the

DOS

detects

that

records1thru99do

not

akeadv

exist,

and

automatically

initializes

thembyplacing

CHR(255)inthe

first

character.

Line

170

closes

the

file

and

causes

the

spacetobe

allocatedinthe

BAM

and

file

directory.

Unes

190-220

are

the

error

subroutine.IfDSisless

than

20,noerror

condition

exists

so

1^210reTZstothp"message,'and

210

returnstothe

mam

programifthe

message

was50RECORD

NOT

PRESENT

If

r^efcrcoSt

sr"

^

EXPANDING

A

RELATIVE

FILE

^ter

the

file

has

been

initiaUzed,

data

maybewrittentothe

fUe.

Initializationofa

fUe

in

IS

ma^er

needbeperformed

only

once

when

the

fileisoriginally

created.Ifthe

user

wishestoexpandanexisting

file,

the

same

procedure

wouldbeused,

with

the

record

num

ber

(hne

130mthe

example)

changedtobe

the

new

last

record.

72

\.

M

The

following

example,

when

with

the

disk

containing

the

file

FILEl

(with

100

records)

in

drive0,will

resultinthe

first

100

records

remaining

unchanged

and

records

containing

only CHR$(255) would be generated for records 101-200.

110 D0PEN#1,"FILEl",DO,L50

120

GOSUB

190

130

RECORD#1,200

140

GOSUB

190

150

PRINT#1,CHR$(255)

160

GOSUB

190

170

DCL0SE#1

180

END

190IFDS<20

THEN

RETURN

200

PRINT

DS$

210IFDS=50

THEN

RETURN

220

STOP

NOTE:

When

DOPENisusedonan

existing

file,

specificationofthe

record

lengthisoption

al.If specified, it mustmatchthe recordlength setat the timethe file

was

created or an

error

condition

will

result.

When

a fileisexpanded in this manner, the required sidesectors are alsocreated. Side

sectors are transparent to the usersince they are automatically generated and accessed by

the

DOS.

ACCESSING

A

RELATIVE

FILE

In order to make the relative filesystem practical,the usermust be ableto

access

the file

for

reading

and

writing

of data.Bothof

these

operations are

simplifiedbyrelative

files

and

both may usethe

RECORD

command

for positioning to the

desired

record beforethe

operation.

Towritedatato a

predetermined

record

ina

file,

a constant maybe

used

in the

positioning

(line

130)

as follows:

110 D0PEN#1,"FILEl",DO

120

GOSUB

190

130

RECORD#l,25

140

GOSUB

190

160

PRINT#1,"RECORD

25"

160

GOSUB

190

170

DCL0SE#1

180

END

190IFDS<20

THEN

RETURN

200

PRINT

DS$

210IFDS=50

THEN

RETURN

220

STOP

The resulting record would appear as follows:

1 2 3 4 5

12345678901234567890123456789012345678901234567890

^

RECORD

25*

Where

* representsa carriage return ( CHR$(13)).

73

74

Mowing

program

Ulustrates

the

feature

which

permits

accesstoindividual

bytes

within

110

DOPEN#1,"FILE1",DO

120

GOSOB

900

130

RECORD#!,25,1

140

GOSUB

900

150 PRINT#1,"FIELD

1"

160

GOSUB

900

170

RECORD#1,25,10

180

GOSUB

900

190PRINT#1,"FIELD

2"

200

GOSUB

900

210

RECORD#1,25,30

220

GOSUB

900

230 PRINT#1,"FIELD

3"

240

GOSUB

900

250 DCL0SE#1

260

END

900IF

DS<20

THEN

RETURN

910 PRINTDS$

920

STOP

placeswithin record

25

after

the

above

exam^"

"

representation

of

the

contentsofrecord

number

12345678901234567890123456789012345678901234567890

FIELD1*FIELD

2*

PTRrnz*

Where♦representsacarriage

return{CHR$(13)).

E™

it

"s's'rsfrs

?ris;r

•i--««.

that

whileitis

possibletoposition

and

write

firsttobvteTfl^Trfh!example,

this

means

possibletofirst

write

byte20and

then

byte

1 "

^OT

d"

basic

input

statement,

the

110

DOPEN#1,"FILE1»,DO

120

GOSUB

290

130RECORD#1,25

140

GOSUB

290

150

REC0RD#1,25,1:G0SUB

290

160

INPUT#1,A$;G0SUB

290

170

RECORD#1,25,10:GOSUB

290

180

INPUT#1,B$:G0SUB

290

190

RECORD#1,25,30:GOSUB

290

200

INPUT#1,C$:G0SUB

290

210 DCL0SE#1

220

END

290IFDS<20

THEN

RETURN

300

PRINT

DS$

320

STOP

Lines

160,180, and200

cause

the

stored

valuesondisk

to be

read

and

stored

inA$,

B$,

and

C$, respectively.

It isextremely

useful

to beableto

access

a record

which

isdetermined

during

program

operation. The following routine illustratesa procedure to query the operator for a record

number

and

data

andtowrite

the

datatothe

disk

file:

100

PRINT

*TYPE

RECORD

NUMBER

AND

DATA"

105

INPUT R,D$

110

DOPEN#1,"FILE1",DO

120

GOSUB

190

130

REC0RD#1,(R)

140

GOSUB

190

150

PRINT#1,D$

160

GOSUB

190

170

DCL0SE#1

180

END

190IFDS<20

THEN

RETURN

200

PRINT

DS$

220

STOP

Line

130

positions the file pointer to record number (R), specified by the user. Note

that

a

variable used in

the

RECORD command must be enclosed in parentheses.

Line

150

causes

the

data

storedinD$tobe

storedonthe

disk.

The RECORD command may be omitted if the file is to be accessed sequentially, which
savestime during program execution. An example of this occurs when writing a large data

base to the disk file. Assume

that

the

program has already dimensioned D$ as an array

which

contains

100

elements.

These

elements

aretobe

writtentothe

diskinrecords

num

ber 1

thru

100

of file

FILEl.

This could be accomplished with

the

following program

segment:

110

DOPEN#1,"FILE1",DO

120

GOSUB

190

130

FOR

1=1

TO

100

150

PRINT#1,D$(I)

160

GOSUB

190

165

NEXT

I

170

DCL0SE#1

180

END

190

IF

DS<20

THEN

RETURN

200

PRINT

DS$

220

STOP

Since

the

record pointer is automatically

settorecord 1 when

the

file is opened, record 1 is

the first record written. If no RECORD command is executed

the

DOS automatically posi

tionstothe

next

record

after

each PRINT. Therefore,

the

contents

of D$ will be written

to

records1thru

100ofthe

file.

For

detailed description of related BASIC commands, refertochapter 4 of this manual and

the

BASIC

4.0

reference

manual.

75

NOTES

n

n

76

r-

Chapter

7

SIMPLIFYING

THE

USE

OF

COMMODORE

DISK-

RELATED

COMMANDS

It has been explained

that

all disk commands

must

be preceded with

the

BASIC

PRINT#

command and enclosed in quotation marks. This is true,

but

your computer can be pro

grammed to perform these tasks as wellas how to load and run programs stored on diskette.

LOADING

THE

DOS

SUPPORT

PROGRAM

The first file on

the

TEST/DEMO diskette contains a program called UNIVERSAL

WEDGE, often referredtoas DOS SUPPORT. This program, when loaded into memory,

takes care of

the

tasks mentioned above. If

your

computer

has Commodore BASIC 4.0

you

can use

the

quick load procedure to load

the

DOS SUPPORT program.

For

those of

you

not

equipped

with

BASIC

4.0,

the

following

procedure

will

work:

Start

with

a cold

start

condition

by resetting

both

the

computer

and

disk drive

and

insert

the

TEST/DEMO

diskindrive

0.

STEP

1;

Type:

L0AD"*",8

and

press

RETURN.

The

screen

displays:

STEP2:Type:

RUN

and

press

RETURN.

^

^is

will

cai^

the

DOS

Support

programtobe

executed.

This

program

will

re

locate

Itself

into

the

topofthe

user

memory,

whereitwill

coexist

with

programs

which

are

entered

later.

DOS

support

will

not

needtobe

reloaded

until

the

com

puterISreset.

The

following

special

symbols,

once

implemented,

will

simplify

the

entryofdisk

commands.

USING

THE

DOS

SUPPORT

SYMBOLS:

>

AND

®

Once

DOS

SUPTORTisimplemented,

preceding

dislc

commands

with

PRINT#lfnorenclos-

ISo

T ^

Trequired:

precede

the

disk

command

with

either

symbol

^y^bol

(>)orthe

at-sign

(@).

The

examplesinthis

manual

use

the

>

Examples:

>10

is

the

same

as

PRINT#1,"I0"

>S0:FILE1

is

the

same

as

PRINT#15,"S0

^J'lLEl"

The

OPEN

statementisNOT

required

beforeastatement.

^th

5

loaded

LOAD

$dr,8but

this

command

destroys

any

program

you

might

haveinmemory

\^en

you

use

the>symbol,

the

dkectoryisprinted

directlytothe

screen,

thusZSg

thedatam the computer's

memory.

pie!,ei:viiig

Examples:

>$0

means

display

the

entire

directoryofdrive

0.

>$1

:Q*

meanstodisplay

all

the

fUesondrive1that

begin

withaQ.

Ki!

SaTSUVetJSd:'"

To

stopadirectory

listmg

and

returntoBASIC,

press

RUN/STOP.

The

third

useof>isthe

requestoferror

messages.

Example:

>

jg

equivalent

to:

10 OPEN2,8,15

20

INPUT#2,A$,B$,C$,D$

30 PRINTA$,B$,C$,D$

LOADINGAPROGRAM

WITH

THE

/

Example:

/ACCT

loads

the

program

ACCT

into

the

computer's

memory.

LOADING

AND

RUNNING

A

PROGRAM

WITH

UP

ARROW

Theuparrow

(t)

loads a program

fromadiskette

and

executes

it.

Both

diskettes are

searched

if necessary.

Example:

tJDATA

loads and runs the program JDATA.

SPECIAL

DOS

SUPPORT

INFORMATION

The

DOS

SUPPORT

program

has

certain

limitations. These

are:

1. The program must be reaccessed from

the

disk whenever resetting

the

computer.

2. DOS

Support

may

only

be used when communicating with

the

disk in direct

mode.

That

is,

they

may

NOTbeused in a

program.

3.

The

disk

directory

maybeprintedonthe

printerbygiving

these

commands:

LOAD

"$0»,8

OPEN

4,4:CMD4:LIST

PRINT#4:CL0SE

4

NOTES

79

NOTES

n

\

80

Chapter

8

ERROR

MESSAGES-

PATTERN

MATCHING

FILE

NAMES-

DISK

COMMANDS

REQUESTING

ERROR

MESSAGES:

COMMODORE

DISK

DRIVES

The execution of the following program displays the error on the computer screen and

resets

the

device

error

indicator:

CBM

Series

2001

CBM

Series

3000

with

BASIC

3.0

CBM

Series

8000

CBM

Series

4000

with

BASIC

4.0

where A=error message

number

B$=error message

C=track

D=sector

82

SUMMARY

OF

CBM

FLOPPY ERROR MESSAGES

0 OK, no

error

exists.

1 Files scratched response. Not an error condition.

2-19

Unused

error

messages:

shouldbe ignored.

20 Block

header

not

found

on disk.

21

Sync

character

not

found.

22 Data block

not

present.

23

Checksum

errorindata.

24 Byte decodingerror.

25 Write-verify error.

26 Attempt to writewith writeprotect on.

27

Checksum

errorinheader.

28 Data extends into

next

block.

29

Diskidmismatch.

30 General

syntax

error.

31

Invalid

command.

32 Long line.

33

Invalid

filename.

34 No file given.

39 Command file

not

found.

50 Record

not

present.

51 Overflow in record.

52 File too large.

60 File open for write.

61 File

not

open.

62

File

not

found.

63

File

exists.

64 File type mismatch.

65

No

block.

66 Illegal track or sector.

67 Illegalsystem track or sector.

70 No channels available.

71 Directory error.

72 Diskfull or directory full.

73

Powerupmessage,orwrite

attempt

with

DOS

mismatch.

74

Drive

not

ready.

(8050

only)

DESCRIPTION OF DOS

ERROR

MESSAGES

NOTE:

Error

message

numbers

less

than20shouldbeignored

with

the

exceptionof01

which

gives

information

about

the

numberoffiles

scratched

with

the

SCRATCH

command.

20:

READ

ERROR

(block

header

not

found)

pie

disk

controUerisunabletolocate

the

headerofthe

requested

data

block,

byan

illegal

sector

number,

orthe

header

has

been

destroyed.

21:

READ

ERROR

(no

sync

character)

The

disk

controllerisunabletodetectasync

markonthe

desired

track.

Caused

by

miMlignmentofthe

read/write

head,nodisketteispresent,orunformattedorimpro

perlyseated diskette. Canalsoindicatea hardware failure.

22:

READ

ERROR

(data block

not

present)

The diskcontroller has beenrequested to read or verifya data block that wasnot

properly

written.

This

error

message

occursinconjunction

with

the

BLOCK

commands

and

indicatesanillegal

track

and/or

sector

request.

23: READ ERROR (checksum error in data block)

This

error

message

indicates

that

there

isan

error

inoneor

more

ofthedata

bytes.

The

data has been read into the DOSmemory, but the checksum over the data isin error.

This

message

may also indicate groundingproblems.

24:

READ

ERROR

(byte

decoding

error)

The data or header has been read into the DOSmemory, but a hardware error has been

createddue to an

mvalid

bit pattern in the data byte.This

message

mayalsoindicate

grounding problems.

25:

WRITE

ERROR

(write-verify error)

This

messageisgenerated

ifthe

controller

detectsamismatch

between

the

written

data

and

the

datainthe

DOS

memory.

26:

WRITE

PROTECT

ON

This

messageisgenerated

when

the

controller

has

been

requestedtowriteadata

block

while

the

write

protect

switchisdepressed.

Typically,

thisis

causedbyusing

a diskette

with a write protect tab over

the

notch.

27: READ ERROR (checksum error in header)

The controller hasdetected an error in the header of the requested data block. The

blockhasnot beenreadinto the

DOS

memory. This

message

mayalsoindicate

ground

ing problems.

28:

WRITE ERROR (long data block)

Thecontrollerattempts to detect the syncmarkof the next headerafter writing a data

block.If the sync mark doesnot appearwithin a pre-determined time, the error

messageisgenerated.

The

erroriscaused

bya

bad

diskette

format

(the

data

extends

into the next block), or by hardware failure.

29:

DISKIDMISMATCH

This

messageisgenerated

when

the

controller

has

been

requestedtoaccessadiskette

whichhas not been initialized. The

message

can also occur if a diskette has a bad

header.

30:

SYNTAX

ERROR

(general syntax)

The

DOS

cannotinterpretthe

command

sentto the

command

channel.

Typically, this

is

caused

byan

illegal

numberoffile

names,orpatterns

are

illegally

used.

For

example,

two filenamesmayappear on the left sideof the

COPY

command.

31:

SYNTAX

ERROR

(invalid command)

The

DOS

does not recognize the command.The commandmust start in the first

position.

32:

SYNTAX

ERROR

(long line)

The

command

sent

is longer

than58characters.

33:

SYNTAX

ERROR

(invalid fUe name)

Pattern matching isinvalidlyused in the OPEN or SAVEcommand.

83

34:

SYNTAX

ERROR

(no

fUegiven)

The file name was left out of a command or the DOS does not recognize it as such.

Typically, a colon

(:)

has been left

outofthe

command.

39: SYNTAX ERROR (invalid command)

This error may result if the command sent to command channel (secondary address

15)

is unrecognizablebythe

DOS.

50:

RECORD

NOT

PRESENT

Result of disk reading past the last record through INPUT#, or GET# commands. This

message will also occur after positioningtoa record beyond end of file in a relative

file. If the intent is to expand the file by addingthe new record (with a PRINT# com

mand),the error

message

maybe ignored.

INPUT

or GETshould not be attempted

after this error is detected without

furst

repositioning.

51:

OVERFLOW

IN

RECORD

PRINT#statement exceeds record boundary. Information is truncated. Since the car

riage

return

which

issentasa

record

terminator iscounted in the

record

size,

this

message

will

occurifthe

total

charactersinthe

record

(including

the

final

carriage

^

return)

exceeds

the

defined

size.

52:

FILE

TOO

LARGE

Record position within a relative file indicates that disk overflow willresult.

60:

WRITE

FILE

OPEN

V/

This

messageisgenerated

whenawrite

file

that

has

not

been

closedisbeing

opened

for

reading.

61:

FILE

NOT

OPEN

This

messageisgenerated

whenafileisbeing

accessed

that

has

not

been

opened

inthe

DOS.

Sometimes,inthis

case,amessage

isnot

generated;

the

requestissimply

ignored.

62:

FILE

NOT

FOUND

The requested file does

not

exist on

the

indicated drive.

63:

FILE

EXISTS

The file name of the file beingcreated already exists on the diskette.

64:

FILE

TYPE

MISMATCH ^

The

file

type

does

not

match

the

file

typeinthe

directory

entry

for

the

requested

file.

65:

NO

BLOCK

This

message

occursin conjunction with the

B-A

command.It indicatesthat the block

to be allocated has been previouslyallocated. The parameters indicate the track and

sector

available

with

the

next

highest

number.

Ifthe

parameters

are

zero

(0),

then

all

blocks higher in

number

are

in use.

66:

ILLEGAL

TRACK

AND

SECTOR

The DOShas attempted to accessa track or sector whichdoes not exist in the format

beingused.This may indicate a problem readingthe pointer to the next block.

67:

ILLEGAL

SYSTEM

TORS

Thisspecialerror

message

indicatesan illegal system track or sector.

84

70:

NO CHANNEL (avaUable)

The

requested channel is

not

available, or all channels are in use. A maximum of five

sequential files

maybeopenedatone

time to

the

DOS. Direct access channels

may

have six

opened

files.

71:

DIR9ectory)

ERROR

The

BAM does

not

match

the

internal

count.

There

is a

probleminthe

BAM allocation

or

the

BAM has

been

overwritten

in DOS

memory.Tocorrect

this

problem,

reinitialize

the

diskettetorestore

the

BAM in

memory.

Some

active files

maybeterminated

by

the

corrective

action.

NOTE:

BAM=Block

Availability Map

72:

DISK

FULL

Either

the

blocksonthe

diskette

are

usedorthe

directoryisat

its

limitof152

entries

for

the

2040,3040,

and

4040or243

entries

for

the

8050.

DISK

FULLissent

when

two

blocks

are

available

on

the

8050toallow

the

current

filetobe

closed.

73:

DOS MISMATCH

(73,

CBM DOS

V2.5

8050)

(73,CBMDOSV2

)

for

4040

DOS 1

and

2 are

read

compatible

but

not

write

compatible.

Disks

may

be interchange

ably

read

with

either

DOS,

but

a disk

formattedonone

version

cannotbewritten

upon

with

the

other

version because

the

formatisdifferent.

This

error

is displayed whenever

an

attemptismadetowrite

uponadisk

which

has

been

formatted

m a

non-

compatible

format.(Autility

routine

is availabletoassist in converting

from

one

for

mattoanother.)

This

message

may

also

appear

after

power

up.

74:

DRIVE

NOT

READY

An

attempt

has

been

madetoaccess

the

8050

Dual Drive

Floppy

Disk

without

any

diskettes

presentineither

drive.

PATTERN

MATCHING

Pattern

matchingoffile

names

is availableonall

Commodore

floppys.

Pattern

matching

uses

^ the question mark (?)and the asterisk (*) to performoperationson

several

files

withsimi

lar

names.

The

asterisk is usedatthe

endofa stringofcharacterstoindicate

that

the

restofthe

name

is insignificant.

For

example:

FIL'*'

could

refertofiles

named

FIL

or

FILEl

or

FILEDATA

or

FILLER

or

any

other

file

name

starting

with

the

letters

FIL.

The

question

mark

may

be used

anywhere

within

the

strmgofcharacterstoindicate

that

the

character in

that

particular position should be disregarded.

For

example:

?????.SRC

could

refertofiles

named

TSTER.SRC

^ or

DIAGN.SRC

or

PROGR.SRC

but

not

SRC.FILES

85

Both

the

characters and

the

positionofthe

characters are significant.

The

question

mark

and

asterisk

maybecombinedinmany

ways:

*J??????

doesnot makesensebecausethe question marksarein an area whichisinsignificant (be

causeofthe

asterisk).

P???FIL*

will

access

files

with

the

names

PET

FILE

or

PRGFILE-32

or

POKEFILES$$

or

any

other

files starting with P and having

FIL

in positions

5-7.

SCRATCH

withpattern matching shouldbeusedcarefully, sincemultiple

files

will

be

scratched.

LOADorDLOAD

will

load

thefirst

file

which

fitsthe pattern

matchmg.

OPEN

or

DOPEN

withpattern

matching

maybe

used

to openan

existing

file,inwhich

case

the

first

existing

file

encountered

which

fits

the

description

willbeopened.

However,

OPEN

or

^

DOPEN

should

not be

used

with

pattern

matching

when

creatinganew

fUe.

Never

use

RENAME,

SAVE,

DSAVE,orCOPY

for pattern

matching

since

an error condition

will

result, if

attempted.

USER'S

QUICK REFERENCE: DISK COMMANDS

The

user's

quick

reference

guide

will

assist

the

userinbecoming

familiar

withthe

various

commands

usedinboth

BASIC

3.0

and

BASIC

4.0,

and

with

the

DOS

SUPPORT

utility

as

well as

with

all

Commodore

disk

units.

In

ordertomake

BASIC

4.0

easiertouse,

disk

commands

have

been

incorporated

into

the

language. For example,with

BASIC

4.0:

•

DSAVE

and

DLOAD

commands

eliminate

the

needtospecify

device

number

each

time

you

store

and

retrieve

disk

files.

• Directory

display

isnowa

one-step

procedure and no

longer

interferes withthe

programinmemory.

• It is no longer necessary to write a programto read the error channel. The variable

DS$ contains the error message.

• Formatting is now a one-stepprocedure through the useof HEADER command.

CommandsinBASIC

3.0

are

upward

compatible

with

BASIC

4.0.That

is,ifyou

are

familiar

with

BASIC

3.0,

those

commands

will

still

work

onthe

Series

8000

Computer

furnished

with

BASIC

4.0. Alldiskcommands

available

on the 2040 are

upward

compatible with both

the

4040

and

8050.

86

Table

17.

User's

Quick

Reference—Disk

Commands

BASIC

3.0

UNIVERSAL

DOS

SUPPORT

BASIC

4.0

SAVE

"dr:fn",8

SAVE"dr:fii",8

DSAVE,**fn",Ddr

(drive

defaultsto0)

LOAD"dr:fh",8

/dr:fn

(searches

both

drives)

DLOAD"fn",Ddr

(drive

defaultsto0)

LOAD"*",8

RUN

tdr:fn

DLOAD"fn",Ddr

RUN

LOAD"dr:fn",8

t*

shifted

RUN/STOP

LOAD"$0",8

UST

(destroys

memory)

>$0

(preserves

memory)

DIRECTORY

or

DKshifted

R>

(preserves

memory)

10

0PEN1,8,15

20

INPUT#l^,B$,C,D

30

printa,b$,c,d

>

return

?DS$or?DS

(DS is

numberoferror

only)

NOTE: Assume

that

0PEN1,8,15 has already been typed for all of the PRINT# com

mands in

the

following formats. Commands

may

be spelled

outorabbreviated by

the

^t

letterasillustrated.

PRINT#l,"Ix"

INITLIALIZE

>Ix

PRINT#l,"Ix"

PRINT#!,"Vdr"

VALIDATE

>Vdr

COLLECT

Ddr

PRINT#l,"Sdr:fn"

SCRATCH

>dr:fn

SCRATCH"fn",Ddr

PRINT#l,"Dddr=sdr"

DUPLICATE

>Dddr=sdr

BACKUP

Dsdr

TO

Dddr

PRINT#1

,"Cddr=sdr"

COPY

(aU

disk)

>Cddr=sdr

COPY

Dsdr

TO

Dddr

PRINT#l,"Cdr:dfn=

dr:sfn"

COPY

(single file)

>Cdr:dfn=dr:sfn

COPY

Ddr,"8fn"TO

Ddr,"dfn»'

PRINT#l,"Cdr:dfh=

dr:sfnl,dr:sfn2,...

CONCATENATE

FILES

>Cdr:dfn=dr:8fl,

dr:sfh2,...

CONCAT

Ddr,"sfn"

TO

Ddr,"dfn"

PRINT#l,"Rdr:dfn=sfn"

RENAME

FILES

>Rdr:dfn=sfn"

RENAME

Ddr,"sfn"

TO

"dfn"

PRINT#1

,"Ndr

:dnamepcx"

FORMAT

A

DISKETTE

>Ndr:dname,xx

HEADER

"dname",Ddr.Ixx

87

NOTES

88

Chapter

9

RANDOM

1.00

PROGRAM

LISTING

This chapter providesa complete listingof the random accessprogram described in Chapter

6 under

the

heading of Random Access Example.

REflDV.

1 REM

RRNDOtI

1.0

2 REM

SUBROUTINES

TO MflNflGE RANDOM

ACCESS

FILES

3 REM

VRRIflBLES

ARE

SET

FROM DATA OF

DESCRIPTOR

FILE

& KEV

LIST

FILES...

4 REM

...DEFINED

BV

USER

PROGRAM

5 REM

VARIABLES

SHOULD

REFLECT

DESIRED

FILE

STRUCTURE

6 REM

ALL

FUNCTIONS

ACT

UPON

THE

VARIABLES

DEFINED

BELOW

le

REM

11

REM

#***#*#*♦#*************#*

^

12

REM

^ 13 POKE1022,128:REM

TURN

DOS

SUPPORT

3.1

OFF

15

M$=CHR$:<13>:REM

FIELD

MARKER

16

SP$="

"+"":REM

SPACE

FOR

PADDING

20

C0=2:

REM

DIRECT

CHANNEL

21

Cl=3:

REM

SEQUENTIAL

CHANNEL

25

CC=15:

REM COMMAND

CHANNEL

30

D=0:

REM

CURRENT

DRIVE

#

31

T=0:

REM

CURRENT

TRACK

#

32

S=0:

REM

CURRENT

SECTOR

#

35

DD=0:

REM

DESCRIPTOR

DRIVE

#

36

RD=0:

REM RANDOM

DRIVE

#

40

ID$="":

REM RANDOM

DISK

ID

45

NR=0:

REM # RECORDS

IN

R-FILE

46

CR=0:

REM

CURRENT

RECORD #

47

FR=0:

REM

1ST

FREE

RECORD UNUSED

50

NF=0:

REM #

FIELDS

IN

RECORD

51

CF=0:

REM CURRENT

FIELD

#

55

RB=0:

REM # RECORDS

PER

BLOCK

56

RS=0:

REM RECORD

SIZE

IN

BYTES

60

NB=0:

REM #

BLOCKS

IN

R-FILE

65

E=0:

REM ERROR

FLAG,

OK

=0

66

REM

EN$,EM$,ET$,ES$,ET,ES

ERROR CHANNEL

VARIABLES^

70

EP=.5/256=

REM

INTEGER

CORRECTION

75

RS=0:

REM INDEX ARRAV

ADDRESSING

STRATEGY

76

REM

AS=0:

USE

ARRAV

INDEX;

AS=1:

T&S ARE

SET,

CR= RECORD

OFFSET

IN BLOCK

90

REM

"A"

VARIABLES

ARE TEMPORARY

95

DN=8:0PENCC,DN,CC:

REM DN=

DEVICE

NUMBER

98

GOTO2000:

REM

START

OF

USER

PROGRAM

99

REM

89

90

100

REM

101

REM

RfiNDOM

FILE

DIMENSION ROUTINE

102

REM

1ST

SET

NR. NF & NB

103

REM

105

GOSUB150

110

IFFPJi=-lTHENRETURN

111

FP;i=-l

115

DIM FS?iCNF) :REM

FIELD

SIZE

120

DIM

FP?S<NF)

:REM

FIELD POSITION

;25

REM

FP?i<I>=

SUM

CFS^<I-0]

}|? S 2 0=

BINflRV.

1:NUMERIC.

2:flLPHa

135

DIM

FH$CNF>

:REM

FIELD

HERDING

140

DIM

F^CNF)

:REM

FIELD ARGS-fiLPHfi.BINfiRV

145

DIM

F<NF)

:REM

FIELD-flRGS-NUMERIC

146

RETURN

150

IFIT?i=-lTHENRETURN

151

IT?i=-l

155

DIM IT?i(NB)

:REM

TRACK

INDEX

ARRAV

160

DIM

IS?i<NB) .:REM

SECTOR

INDEX

ARRfiV

165

DIM

K1$<NR)

:REM

PRIMARV

KEV

VALUE

lit

SiC

=REM

RELATIVE

RECORD

LIST

PER

KEV

175

RETURN

200

REM

201

REM

UPDATE

RECORD, CR

202

REM

205

GOSUB900

210

PRINT#CC,"U1•"C0;d;T;s

215

PRINT#CC,"B-P:"C0;RP

220

F0RCF=1T0NF

225

GOSUB500

230

NEXTCF

235

PRINT#CC,"U2:"C0;D;TjS

240

GOSUB1000:IFETHEN1900

245

RETURN

300

REM

301

REM

READ

RECORD,

CR

302

REM

305

GOSUB900

310

PRINT#CC,"U1:"C0;D;T;S

315

PRINT#CC,"B-P:"C0;RP

320

GOSUB1000:IFETHEN1900

325

FORCFslTONF

330

GOSUB600

335

NEXTCF

340

RETURN

400

REM

402

REM

FIELD(CF)

OF

RECORD

CR,

SINGLE

FIELD

UPDATE

405

GOSUB900

410

PRINT#CC."U1:"C0;D;TJS

415

GOSUB1000:IFETHEN1900

420 PRINT#CC,"B-P:"C0;FP?i<CF)+RP '

425

GOSUB500

:REM

UPDATE

FIELD

430

PRINT#CC,"U2:"C0;D;T;S

435

GOSUB1000:IFETHEN1900

440

RETURN

450

REM

452

rIm

O""

"ECORD

CR,

SINGLE

FIELD

READ

455

GOSUB900

460

PRINT#CC,"U1:"C0;D;T;S

465

GOSUB1000:IFETHEN1900

470 PRINT#CC,"B-P:"C0;FPX<CF)+RP

475

GOSUB600

:REM

READ

FIELD

480

RETURN

500

REM

501

REM

UPDATE

FIELD<CF>,

B-P IS

SET

502

REM

510

IFFTJi<CF)OlTHEN520

530

PRINT#C0,A$;M$;

535

RETURN

600

REM

601

REM READ

FIELD<CF).

B-P

IS

SET

602

REtl

610

IF

FT?i<CF)

THEN645

615

fll$=""

620

FORJ=lTOFSJi<CF)

625

GET#C0,fl$:lFfl$=""THENfl4:-CHR$<0)

630

fll$=fll4:+fl$

635

NEXT:F$<CF)=flU

640

GET#C0.flf:RETURN

645

INPUT#C0.F$(:CF>

650

IFFTX(;CF)01THEN

RETURN

655

F<CF>=VflL<:F$<CF>):

RETURN

700

REM

701

REM

ALLOCflTE

ONE

BLOCK.

T & S

=REQUESTED

TRRCK

SECTOR

702

REM

RETURNED

T & S fiRE

RLLOCflTED

VALUES

<T=18

IS

SKIPPED)

703

REM

^ 710 GOSUB800:IFETHEN1900:

REM

CHECK

T S

'^

715

PRINT#CC."B-fl:"D;T;S

720

INPUT#CC/EN.EMf.ET/ES

725

IFEN=0THENRETURN

730

IFENO65THEN1900

735IFET=1STHENTs

19:

S=0

60T0715

736

T=ET:S=ES

740

G0T0715

750

REM

751

REM

FREE

ONE BLOCK. T S = TRACK & SECTOR

752

REM

760

GOSUB800:IFETHEN1900:

REM

CHECK T & S

770

PRINT#CC."B-F:"DjT;S

780

INPUT#CC.EN.EM$,ET.ES

785

IFEN=0THENRETURN

790

GOTO1900

800

REM

mmmmmmmmmmmm-*

801

REM

CHECK

MAX

SECTOR

802

REM

810

IFT>35THEN1900

820

E=0:1FT=0THEN=40=GOTO1900

840

A3=16:IFT>30THEN880

850

A3=17:IFT>24THEN880

860

A3=19:IFT>17THEN880

870

R3=20

880

IFS>A3THEN1900

890

RETURN

900

REM

901

REM

SET RECORD'S

TRACK.

SECTOR

RECORD

POINTER

FROM

INDEX

ARRAVS

902

REM

905

D=RD

910

E=0

9151FRS=-1

THENRP=CRitiRS+1:

GOTO950

920

RP=INT<<CR-1)/'RB+EP):IFRP>NB

OR RP<0THENEN=41 =

GOTO

1900

930

T=IT?i<:RP>:S=IS:i<RP>

940

RP=INT<<<CR-1VRB-RP+EP)*RS*RB)+1

950

IFRP>254THEN

EN=41:GOTO1900

960

RETURN

1000

REM

1001

REM

INPUT

2040

ERROR

STATUS

1002

REM

1005

INPUT#CC.EN$.EM$.ET.ES

1010

EN=VAL<EN$):E=0

1015

IF

EN$="00"

THEN RETURN

1017

ET$=STR$<ET):ESf-STR$<ES)

1020IFEN^OR

IGHT$<"0 "+MID$<STR<:<EN>. 2 >. 2 >THEN

1070

1030

IF

EN=1 THEN EM$=

EJ$+"

"+EM$:

RETURN

1035

E=E+1

1040

EM$="a"+EN$+"5

"+EM$

1050

IF

EN<30

OR EN=65

THEN

EM4:=EM#+" ON

"+ET$+".

"+ES$

1060

RETURN

^

1070

EM$="aBVSTEM

NOT

RESPONDING PROPERLV"

1080

EM$=EM$+EN$+EN$+ET$+ES$

1085

E=E+1

1090

RETURN

91

92

1100

REM

1101

REM

CREATE

DESCRIPTOR

FILE

1102

REM

input:

F$=

FILENAME

1103

REM

ID$>NR.NF/FS?J<>,FT;i<).FH$<)

1104

REM

DD=^DESCRIPTOR

FILE

DRIVE

#

1105

REM

RD=

RANDOM

DISK

DRIVE

#

1106

REM

DRIVES

MUST

BE

INITIALIZED

1109

REM

1110

RS=l:D=RD

1115

FORA0=1TONF: FP^i<A0 )

=RS:

RS=FSfi

<A0>

+RS+1:

NEXT:

RS=RS-1

1116

RB=INT<254/RS+EP>

1120

OPENC0/DN/C0."#":GOSUB1000:IFETHEN1900

1121

GOSUB1280

s

1122

PRINT#CC."B-P:"C0;l

1123

FORA0=1TORE:F0RR1=1TONF

1124

PRINT#C0.LEFT$<SP$,FS?i<A1

>);;

1126

NEXTR1.A0

1130

NB=INT <

NR/RB+EP):IF

<NR/RB-NB)*RB>=1THENNB=NB+1

1135

T=l:S=0:GOSUB150

1140

FORA0=0TONB-1-GOSUB710:IFETHEN1900

1145

IT?i<:R0)=T:IS?i<fl0>=S:GOSUB430:NEXT

1150

GOSUB710

1152

PRINT#CC,"B-P:"C0;1

1155

PRINT#C0,NR;M$;1;M$;nb;m$;rs;M$;RB;M$;NF;M$;

1160

print#cc,"b-w:"C0;d;t;s

^

1165 Af=STR$<DD>+":"+LEFT#<F$+SP4:/10)+".DESCR.U.W" ' ^

1166

OPENCl.DN.Cl.RI:

1167

GOSUB1000:IFETHEN1900

1168

PRINT#C1.

ID$;M^;T;M$;S;M$;

1170

FORA0=1TONF:

PRINT#C1

>CHR$(FS;i<A0)>;

CHR$<FT;i<A0>);FHf<A0>;

M$;=NEXT

1175

FORA0=0TONB-l:PRINT#Cl.CHR$<IT?i<:A0>);CHR$(IS?i<A0>>;

:NEXT

1180

CLOSECl:CLOSEC0:RETURN

1200

REM

1201

REM

OPEN

RELATIVE

FILE

1202

REM

INPUT:

F$=

FILENAME

1203

REM

DD= DESCRIPTOR

FILE

DRIVE #

1204

REM

RD=

RANDOM

DISK DRIVE #

1205

REM

DRIVES

MUSTBEINITIALIZED

1209

REM

1210

flf=STR$(DD>+":"+LEFTf<F$+SP«:.10)+".DESCR.U.R"

1215

OPENC1.DN.C1.R$:GOSUB1000:IFETHEN1900

1220

INPUT#C1.ID^,T,S

1225

OPENC0,DH,C0.GOSUB1000:IFETHEN1900

1226

GOSUB1280

1227

PRINT#CC/"B-R:";C0;RD;T;S:GOSUB1000:IFETHEN1900

1230

INPUT#C0.HR.FR,NB.RS/RB.NF

1235

GOSUB100:FT?i<0)=T:FS;i<0>=S

1240

FORR0=1TONF:GOSUB1298:FSX<R0)=RSC<

A$)

1245

GOSUB1298: FT?iCA0>^ASC<R$ >

1250

INPUT#C1,FH$<A0>:NEXT

1255

FORA0=0TONB-l:GOSUB1298:IT?i<A0>=ASC<A$>

1260

GOSUB1298:1S?i<A0)=ASC<A$>:

NEXT

1265

GOSUB1000:IFETHEN1900

1270

CLOSECl

1275

RETURN

1280

PRINTftCC/

"ur-

";C0;RD;

'M8.0":GOSUB1000:1FETHEN

1900

1285

PRINT#CC."B-P:";C0;162

2iI*i®''^^'^l^"f^^=f'^+fil^=

IFID^<>fl^THENEN=43:EM$a"WRONG

RAND

DISK"

:GOTO

1900

RcTURN

1298

GET#Cl.A$:IFfl$=""THENA$=CHR$<0>

1299

RETURN

1400

REM

1401

REM

CLOSE RELATIVE

FILE

1402

REM

INPUT:

VARIABLES

FROM

OPEN

SHOULDBEVALID

1409

REM

1410

PRINT#CC."E-P:"C0;1

1420

PRINT#C0.nr;m$;FR;m$;NB;M«:;R5;m$;rb;m$;NF;m$;

1430

PRINT#CC."B-W:"C0;D;FT?i<0);FS?i<0)

1440

CLOSEC0

1490

RETURN

1900

E=E+l:RETURN

2000

INPUT-nSfilDO

VOU

WISH

TO

CREftTE

fl

FILE

IFLEFT$<R$,

1)O"V"THEN2100

2001

INPUT"WRflNDOM

FILE

NRME";Ff

2002

IHPUT"KEV

FILE

DRIVE

NUMBER";DD

2003

INPUT"RftNDOM

FILE

DRIVE

NUMBER";RD

2005

INPUT"ENTER

ID

OF RANDOM

DISK

-JMII";

ID$:

ID$=LEFT$<:iD$.2)

2006

INPUT"NUMBER

OF

RECORDS";NR

2007

INPUT"NUMBER

OF

FIELDS

PER

RECORD";NF

2010

GOSUB110

2015

PRINT"W

INPUT

FIELD

NfiME.FIELD

SIZE.FIELD

TVPE"

2016

PRINT"

TVPES:

0=BINflRV.

1=HUMERIC.

2=flLPHflW"

2019

RS=0

2020

FORI =

1TONF:

PR I NT"FIELD

";

I.

: I NPUTFH$ <H >FS?i <I >,

FT/i

<I > =

RS=FS?i

<I

>+RS+1

=NEXT

2025

fl$="I":IFDD=RDTHENflf="I"+STR$<DD>

2030

PRINTttCC.fl^

2040

GOSUB1100:IFETHEN3300

2050

0PEH4

>8.4,STR$

<DD

>+"

=

"+LEFT$

<

F$+SP$

>10

>+".KEV01.U,W"

2055

PRINT#4,0;M$;:CL0SE4

2090

GOTO2120

2100

REM OPEN

RANDOM

FILE

FOR

ACCESS

2103

INPUT")iRANDOM

FILE

NRME";F$

2105

INPUT"KEV

FILE

DRIVE

NUMBER";DD

2110

INPUT"RANDOM

FILE

DRIVE

NUMBER";RD

2120

GOSUB1200:IFETHEN3300

2140

0PEN4,8,4,STR$

C

DD)+":"+LEFT$

<

F$+SP$,10)+".KEV01>

U"

2142

INPUT#4,RR:IFRR=0THEN2147

2145

FOR

I=ITORR:

I

NPUT#4,

K1$ <

I),

RR?i< I > =NEXT

2147

CL0SE4

2150

PRINT":i»$ffili»iii»i»niiiiBAMPLE

random

ACCESS^"

2155

PRINT"TVPE

//

TO

QUITW"

2156

PRINT"<HIT

RETURN TO ADD

RECORD)"

2160

PRINT")!WIJH0SE

RECORD DO VOU"

2161

INPUT"WISH

TO

SEE

liirSRR*

2165

IFRR$="

"THEN2310

2167

IFRR$="/'/"THEN2400

2168

IFRR$="/DIR"THENGOSUB4000

=

GOTO2160

2170

FOR11=1TORR:IFK1$

<11)ORR$THENNEXT

=GOTO2300

2175

CR=RR*^<11>:

GOSUB300

2180

FORI=1TONF:PRINTI;")"FH$

<I>":".F$

<I)=

NEXT:PRINT

2185

FF=0

2190

INPUT"flNV

MODS

IMI";A$:

IFLEFT$<A$,

1)O"V"THEN2220

2195

INPUT"WHICH

FIELD";A

2200

PRINT"

"F4:(A>:PRINT"n";

:INPUTF$(fl):F<A>=VAL<F$<A>)

2210

FF=l:GOTO2190

^

2220

IFFF=0THEN2160

^ ^

2222

IFA=1THENK1$<ID=F$<A>

2225

GOSUB200

2230

GOTO2160

2300

PRINT"^RECORD

NOT

PRESENT"

2305

INPUT"DO

VOU

WISH

TO

ADD";A$:IFLEFT$<A$>1)O"V"THEN2160

2310

PRINT")S»###

ADD

RECORD

mmm"

2312

IFFR>NRTHEN2500

2315

CR=FR-FR=FR+1:RR=RR+1

2320

FORI=1TONF

=PRINTFH$

<I>;:INPUTF$

<I):F

<I)=VAL<F$

<I))=

NEXT

2330

GOSUB200

2340

Kl$<RR)=F$<l):RR/i<RR)=CR

2350

GOTO2160

2400

REM CLOSE RRND

FILE

2405

GOSUB1400

2410

0PEN4,8,4>"e"+STR$<DD>+":"+LEFTf<F$+SP$,10>+".KEV01.U,W"

2420

GOSUB1000:IFETHEN3900

2430

print#4,rr;m$;

2440

F0RI=lT0RR:PRINT#4,Kl$<n;M$;RR:«I>;M#;

:NEXT

2445

GOSUB1000:IFETHEN3900

2450

CL0SE4

2455

GOSUB1000:IFETHEN3900

2490

POKE1022,8:END:REM

TURN DOS SUPPORT

3.1

ON

2500

PRINT"THE

FILE

IS

FULL,

NO

ADDITIONAL

RECORDS

MAV

BE

ADDED"

2510

GOTO2160

^

3900

PRINTE,EM$:STOP

^ 4000 FORDI=0TONR:PRINTKU<DI>:next:RETURN

93

' '' • i

•;*

•

94

NOTES

•• :

. " ' ' • \ '' " ' ".i i'' •L

• " • • - ' ^- . ' : -

i;;-;

• • . ^

• • • • • •

•'

rn:-^

•

.<•

• • • ,

'••

^'^v-vv

•

-•

i;,'-

.>•:

' •'.••• ••••••

• • ' ^

•.

- :S^::

••

" • - V'•- • i m'-:---

. r i-;:;

- ' •

••'••

=

"fv

•,

, < ' - w '

•'•••"•ir-iiA;-

••••V

- • • - • V - • ;•.. •

wt'r;,

; .

•I ' •

•••"

T -

• •

"

v-v

• •-•"!

•v.

..-r•...

...

;•:

:-

..r.

• • ^ ' V• J

•;v• ,

••;

ri

-iO'-;,:-

•••v .- ;