IBM 3340, 3344 Reference Manual

GA26-1619-4

File No. 5370-07

Reference

Manual for

Systems

IBM

3340/3344

Disk Storage

IEnfi

PREFACE,

This

publicatic,n

is

intended

to

familiarize rCata

proc-

essing

personnel

lvith

the characteristics

ol' IBM

3340/3344 Disk

Storage. The

reader

should

have

prior

knowledge

of direct-access

storage

dievices

and

concepts.
This

publication

is organized

by topics

as follows:

r

INTRODTiCTION

-

Describes

basic unirs

and

lists

highlights

and f'unctions.

o

CONFIGTJRATIONS

and ATTACHVIENTS

-

Defines sorne

possi'trle

combinations

and svstem

attachments for

the 3340i3344.

o

FEAT'URF,S

-

Describes

both

standand

and

optional fe:rtures

available for

the 334(l/3344

with

illustrations

of some

combinations.

o

FORMATS

-

Describes

and illustrates

thc record

and track Irtrnrats

for

data. Also

provided

are

Record,i T'rack

capacity

charts including

formulas

for

capacitll

calculations

of

various

length

records.

o

INPUT/OLTTPUT

-

Includes

addressing

methods.

access tintes.

and identifies

security

and

privacy

me:ans.

Lists and

summarizes

the

3340/3341

command set

and sense

byte

formats.

Also includes

an

error condition

table and the

associated

{lrror

recovery

actions.

o

OPERAI lNG

INSTRUCTIONS

-

Describes

all

switches anrd

indicators

associated with

tht:

Fifth

Edition

(July

1975)

'Ihis

pubf

ication

rcplaces

arrd nrakcs

Re.l'erence

Manuul

{r:r

lBll[

-t -]40 Disi

Storase,

Ordcr

\,r.

GA26-1619-1.

obsolctc.

Significant

chattg,:s trr

addilions

to thc specifications

containcd in

this

nubliearrgn

are continually hc-ing

ntade . Bcforc

usttrg

ihis

grubliczrtion

irr

corrnection

with the

operation

of IBM

equiprnent,

c()ntact the

loc:rl IBM

Branch

()flice

f or rcvisions.

copies

of this arrd

other [81\1

publications

can

be obtained

thr<iush

ll]ful llranclr

C)ffices.
.A form for

readcr's

rommcllts

is

provi<1ed

at

thc back of

lliis

nublicalion,

lf thr:

fornr has

been re ntovcd.

send

vour

c()ntinent:,

to the adclress

h,:low.

'fhis

nranual

was

prepared

by thc IBM

Gc'cral

Pr'duc1s

[)ivision.

Craphics

and

Publishing.

Departmcnt

G26. San

.,Iose. Claiifornia 95

193.

!:'

Copyright lnternational

Ilusincss

Machines

Corporation

lg7

j.

1974, 1975.

3340/3344

Operator and Power

Panels. Provides

suggested

instructions for

data module

unloading

and loading

procedures

and

the EnableT'Disable

Read

Only

Function.

The

following

publications

are recommended

for

detailed information

concerning the

subjects covered

in

this manual:

c

IBM

System/370 Principles of

Operatlon,

Order

No.

GA22-7000.

c

IBM 3348 Data

Module Handling Procedures,

Order No.

GA26-1625.

o

IBM

,1

340 Disk

Storage Fixed Head

Feature

Users

Guide. Order No. GA26-1632.

c

IBM Reference

Manual

for

Integrated

Storage

Contol.

Order No.

GA26-1620.

o

IBM Reference

Manual

.f-or

3830 Model

2

Storage Control,

Order

No.

GA26-1617.

o

The Data Processing

Glossary,

Order

No.

GC20-

|

699, define s terms related

to direct-access

storage

devices.

o

Thc functional

characteristics manual

applicable to

thc

parent

system.

C)rcler

numbers for functional

characteristics manuals

can be found in the IBM

.S.y.stem/

360 and

System/ 370

Bihliography,

Order

No.

GA22-6822.

ii

IBM

334014'1

Re

ferencc

Manual

Introduction
IBM

3:140

Disk

Storage

DataModule....

Defect

Skipping

IBM 3344-82ll]2F Disk

Storage

. . .

.

IBM

3340/3344 Units

3340/3344

Storage Clontrol and

Features

Storage Control

Devices

Special

Features

StringSwitch....

Rotational Position

Sensing

Fixed Heirds

Configurrations....

3340

Stc,rage

Without

3344 .

Modeli I l5

(115

DDA)

Modet

1'25

(125

DDA)

ModeL

13-5

(IFA)

Moclels

135. 145. 155-ll, 158, 165-ll,

ancl

l68

(3830-2)

Models 145, l5B.

ancl

168

(lSC)

3340/3344 Configurations

. . .

Model l.15

(IFA)

Models

135,

145, 155-tl. 158, 165-ll.

anrl

168

(3830-2)

Models 145, 158,

and

168

(lSC)

IBM 33418 Data

Module . . . .

Data Mc,dule

Types

Data Mo'duh

Initialization . .

.

Data

Surfacc

Format

Formats

Record Format

Count

Area
Key Area
Data

Area

TrackFormat....

Home Acldress
Track

Descriptor Record

(R0)

DalaRecords....

'frack

Capacity

Input/Output Operations

Device Selection

and

Addressing . . .
Device Address
SeekAdclress

...

Access

and Data

T'ransfer Speed

.

Pagc

ol

(iA26-1619-,1

Rcviscd

May 16.

lt)76

By'l

NL:

(;N26-012ti

CONTENTS

Access

Motion Time .

Head Selection

Time

Rotational Delay

.

Data

'l'ransfer

l1

Data Security and Privacy

. . 11

Read Only

Function

11

FileProtection...

11

Seek

Verification .

11

ErrorRecoveryProcedure..".

18

Error

Correction

Function . .

.

18

Error Condition

Table

ltJ

Error

Recovery Action

l8

Constructionof

RestartCCWs

.......

l8

Channel Commands
Sense Commancls

.

Control Commands

Rcad

Commands

.

Write Commands

.

Search

Commands

Sense

Data

Sense

Byte

Suntmary

ScnseBytesO-7Suntmary...,

-15

3340 Sense

Byte Format I Summary

l(r

3344

Sense Byte

Fornrat I

Summary

-lti

Formats

l,

4,

and 5

Message Summary

40

Sense

Byte Format 4 Summary

1l

Sense

Byte Format 5 Summary

4)

Sense

Byte

Format 6 Summary

'+-3

Operating

Instructions

3340 Operator

Panel

3344

Operator

Panel

3340/3344

Power Panel

.

Machines

Without String

Switch

Feature

Machines

With Strins

Switch

Feature

Data

Module Loading

Data Module Unloading

4()

Read Only

Function

'+7

Enable

Read Only F-unction

1'1

Disable

Read Only

Function

1l

Index.

48

t6

l6

t1

3
3
3

3
3

3

4
4

A

4
4

l.)
i-)

_-)

J)

-:)

i)
l4

j'1

4

.4

4

,+4
44

14

4l
4-\

46

6

6

6

6

8
8

6

d

8

8

d

8
8

9

lo

l6
l6

IO

16

Conte

nts

iti

['a-ec

t'l

C,'\]ri-

l(r

l9-.1

Rt'viscd

\1ay

2(r.

l9

/(,

tsy'l

Nt-:

(;\16-().1:tt

FIGURES

Figure l.

Figure

2.

Figure

3.
Figurc 4.
Figure

5.

l'igure

b.

Figure

7.

Figurc

8.
Figurc

9.

Figure 10.
Irigure

I I .

Figure 12.

Ittlvl

3340/:1,144

Disk

Storaire . . .

IFA

3340/-i344

Maximunr

Cenl'isuralion

ISC or

3IJ30-2

Maximurn

Llonl"isuration

l)ata

Surface'l'rack

l-ay,out

. . .

. .

l)ata

Module

(ieonrctrv

l{ecord

and'l'rack

Formar

l'rack,/(lyiinclcr

C:.ipacitir:s

-

No

Kcls .

Darta

Module

Capacitics

-

Ntr

Keys . . .

.

-l-rack,/Cylincle
r

Capracrtrcs , Wirh

Kcys

Data fr4oduie

Capaciticr

,

V'1irh

KL:y's

Errclr

C<inclitiorr fehlc

Rccovery

Actiorr

'l

ablc .

lic:nse Lurnrnand\
(

lontrol

(.

onrnrirrrils

Rcaci

(-ornnrarrds

Writ.e

(.'ornmanLls

Search

(.'ornnrarrrls

Scrrsc

[3yt.es

(.]-

J Sumnrary . . . . . .

-J-1.10

l'orrlrat

i 5c;tsc

llttc

Suniltrarv . . . . . .

-l.l-1.1

l orrrurl

I

Scn:;c

Bytc

Sunrutary"

. - .

lrormats l. 4,

and 5 Messap'.q'

Surnirr.rrv

Fornt.rt

-l

Sulrrnrrry

I olmut

-5

Surt)nliir)

Frrfilli-rl 6 Sutilnlltrv

Opcrator Panc:i, ll-140 ancl

3j"l4

"

Powcr l)arrel,

334f) / 3341

ljata Module

[.oad,'Linlrred

llttrtl

()lriv

l,rr(

ll.tl

5
)

l(r

)l

-19

-)l

ll
,15
36

-18

10
4l
.1

,l

-tr.1
:i4

,16
,47

it

llJ\l .i.lJU,.++

Rclu,rr.tr.t' Iilrrru:rl

The IBM 3340

Disk

Storage

provides

direct-

access storage

for IBM

System/370

Models I

15, 125,

135, 145,

155-II,

158,

165-II,

and 168.

The 3340

consists

of a Model

42, control

with

dual-drive

disk

storage,

and up

to three

attached

dual

(B2)

or single

(Bl)

drive units.

The 3344large-capacity,

dual-drive

unit

can

be substituted

for

the 3340

B-type

units

on IBM System/370

Models

135,

145, 155-ll,

158.

165-II,

and 168.

The

3340/3344 is

a modular,

high-speed,

large-

capacity disk

storage

subsystem

for

data base,

data

communication,

or

general purpose

use.

IBM 3340 DISK

STORAGE

The IBM

3340 direct-access

storage

introduces

two

technological

advances:

a data module

and

defect

skipping.

Data

Module

The

sealed data module

cartridge

contains

storage

disks,

drive spindle, read

and write

heads,

and access

arms. The data module

has

several advantages

over a

disk

pack:

o

The drive

data storage

capacity

can be changed

by

using a different

data module.

o

The

heads, storage

disks,

and drive

spindle are

sealed inside

the data

module.

This avoids

contam-

ination from

outside

sources

and reduces

preven-

tive maintenance.

o

Reliability

is

improved

as

each head

reads

only the

data

that it

previously

wrote.

Defect

Skipping

Defect

skipping allows

data to

be stored both

ahead of

and following

a surface

defect. All

of the recording

track can

be used except

for minute

portions.

Since

the heads no longer

need be moved

to an alternate

track, access time

is saved.

Data module

capacity is not

changed

by defect

skip-

ping

and

t.he user is

rinaware of

defects.

INTRODUCTION

IBM 3344-B2IB2F DISK

STORAGE

The

IBM

3344-BZlB2F

dual-drive unit

provides

increased

capacity, lower-cost-per-byte,

direct

access

storage.

Each

3344

drive stores four

times the

quantity

of data of a 7O-megabyte

data

module

by

using fixed

media. The 3344 dual

drives

can

replace

the

3340

B-drives in a 3340

string on IBM System/

370 Models

135, 145, 155-II, 158, 165-II,

and

168.

The

3344-B2F

contains fixed

head

storage.

Defect skipping,

similiar to that

used

on the 3340,

is also

used

by the

3344-B2|B2F.

IBM

3340/3344

UNITS

^fhe

334O/3344

disk storage

is made

up of a

maximum

of four dual-drives.

The

input/output interface

is a
3340 Model A2 containing two independent drives
and

their control logic.

Up

to three additional

attached dual-drives

are controlled by the A2

unit.

The 3340 Model B

contains

either

one or two drive

mechanisms.

The Model 81 contains a single drive;

the Model

82 contains two drives. Each model

contains

all necessary electronic and

power

supply

circuits for internal use, but data control and

power

sequencing

comes from the

A2 unit.

The

3340 Models A2,B2, and

Bl

use the 3348 data

module

as a storage medium.

The

3344 dual-drive models use

fixed

media storage

instead

of a data module. The

following

characteris-

tics apply

to both storage device

types

except that the

3344

storage

capacity is279.5

million

bytes-per-drive

and start

time

is

not significant

because

the storage

is

not moved.
The 3340/3344

offers the

following:

o

Start

time

-

less

than

20 seconds

o Average

access

time

-

25 milliseconds

o

Average

rotational delay

-

10.12

milliseconds

o

Nominal

read/write rate - 885,000 bytes-per

second

r

Data

module capacity - 34,944,'768

or 69,889,536

bytes

Introduction

I

IBM

3340-A2

(Control

and Two

Drives)

CONTROL
.

Interprets

and

executes

macro-orders

from the

storage control

r

Regulates the

storage control and

disk

$torage

interfaces

o

Serializes and deserializes

data

r

Checks data integrity

by error detection

and

error

correction analysis

o

Furnishes

status

to the

system

o

Performs

diagnostic evaluation

of the

3:140/3344

storage stnng

DRIVES

o

Responds to

commands from the

3340-42

(controller)

o

Houses, loads, filters,

and drives

a 334t| data module

which has various

capacities

(Models

31i, 70, and

70F)

r

Positions

access mechanism

with voice-coil

and

maintains track following

with

electronir: servo

system
Selects

the head

Reads

or

writes

data

Provides

safety

and

servicing

information

for

subsys-

tem

and system evaluation

Figure l. IBM

3-140/3344

Disk Storagc

IBM

3340-8l

(One

Drive), IBM

3340-82

(Two

Drives),

and IBM 3344

(Two

Drives)

r

Responds

to

commands

from

the 3340-42

(controller)

r

Positions access mechanism with

voice-coil and

maintains track following with

electronic servo

system

r

Selects

head

r

Reads

and

writes

data

r

Provides safety and

servicing

information for

subsys-

tem

and system evaluation

3340-81 and 3340-82: Houses, loads, filters, and

drives

the

3348 data

module(s)

of

various

storage

capacities

(Models

35,

70, and 7OF).

3344-82 and 3344-B2F:

Houses, filters,

and

powers

two fixed media

drives.

Each 3344

drive

is

equivalent

in

capacity and

format

to four

logical

3348 Model 70

volumes, a total

of

279.5

million bvtes of data.

a
a
a

2

IBM

3340144 Reference Manual

STORAGT]

CONTROL

DEVICES

'[he

followirlg

storage

control

clevices ciln accommo-

datc 31140

133,14

clisk

storiiP.o.

o

3lt30

Storagc Control

lvlodel 2.

o

Systcnr,l-170

Moclcls

l5lt and

l(rl{ llltc:p'1a1sd

Storage

(

lontrol ( ISC--).

r

Syr;tcm7/-170

Modcl

145

lSCl.

o

Sy:;tem,/370

Model

145 Storagc Cttntrol

Fr:ttnc

3345

Models 3,

4,

and 5.

o

Systcm,/370

Model

135 lntcgratc:cl Filc

Attlrch-

rnent

(lFiA).

SPECIAL

}'EATI-]RES

I'he 3-14(J

drsk

storage has

four special

lcaturers

'Ihe

Model A2 can

he'

supplied

rvith

the strirrg

switch and

thc

rcmotc l;witch.

All 3340

ntodels cau bc ordered

with Rotational

Positicln Sensing

and

Fixecl

I lcad

Storage.

Thc

3344

tiisk stclrage

has

no spccial

leatures.

iis

Rotational

Positi<>r.r

Sensing

is

standartl. Fixed

llead

Storage is available.

but

must

be tlrdercd

Lry nroclcl.

l'he 3344

l\{oclel

R2F contains

l'ixed

hcad storaqe

anti

the

Model

Il2 does

not.

String

Sn'itch

'Thc

string

:i'witch

fe atttrc

is installcd

on thc 3340-42

(controller)

'I'his

[e'ature

pcrrrtits

thc 3340

strins t<r

bc

dynamicully

sharecl

by two

slorage control

tlcvices

-I'he
fcaturc'

inclrrclcs

two

intcrlockccl

F-,na[rlc,/Dis:rhlc

switchcs alkrwing

the

strirrg

1o

bc

declicirtcd

to

crthe r

storalle control

ttr acc:cssihle

by

cach.

A re ulotc

contr()l

srvitch

pcnnitting

thc switclres

to

hc activatc<l

lrom a

l5li

or l6lt

Nlultipr<)ccssor

is also lrvailablc.

3340/3344

STORAGE

CONTROL

l'age ol

(i

Al.6- |

(r

I

()--l

Rcvrsccl M:rv 2('. l()76
Iiv

-l'Nl.:

(;N26-O.r2l{

AND

FEATURES

Rotational

Pnsition

Sensing

Thc

Rotatittnal

Position

Sensing

(RPS)

fcattlrc-

recluces

lhe channel

contrection

timc

requirecl

to

scarch for

a

given

recortl al'te

r thc

track

ancl hcad

have

treen

sclccted.

This

ferature

(optional

tltl the 33"10,

stanclard

<in the 3344)

disconnects

ther

drivc

from thc

channcl

anrl

pe

rmits

other channe

I operations

to

bc

rlerfornred

during

the

timc

requirccl

for the

spinclle

to [rring

the

rctluircd

rccortl

to the

re

rrd

z

writc hcatl.

Additi<lnal

cletails

on

RPS ancl

its associate

cl conr-

mancls

arc

fottncl

in thc

following

ptrblicati<lns:

c

Re.ferente

Mattutt/

f'or

Integraled

Stt;roge

C'ontrol.

Orclcr

No. CiA26-I62.0.

o Re.ft:rent'e

Manuol

for

-18-1

0-)

Storage

C'ontrol,

()rclcr

No. GA26-

1617.

F'ired

FIeads

1'hc 3340

lixccl

heacl

feature

pcnnits

use

ol thc

334t't-70F

data

rnodule

on

ar.ry

3340

drivc tl'rrt

has

[-reen

converted

for

fixed

hear-l

r.rsc. This

70-mcgabytc

cleta

mclilulc

contains

lixed

heads

in addititlu

ttl

tl.tc

rrormal

acccss

hcacls.

With

thcsc

l'ixed

heacls. 500

tl.rousancl

hytcs

tll st()rage

are

availablc

that

have ze

r<r

seek

timc.

Thc

fcrttttre

tlocs

not ittcrease

data

trroclttle

st(.)rage.

bccattse

an equivalent

ltllloLlnt

of storagu'

runctcr

thc

ntovit-tq

hclds

bcconrcs

inaccessiblc.

'I'hc

3344-R2I:

clual-dril'e

is also

cquippcd

with

fixed

he rd

st<lragc.

ln this

nl<lclcl,

both

3344

tJrivcs havc

I .004

milliotr

fryte s of

zero

seek

title

storallc.

This

fixed

hcad

storagc is

associatecl

tlnly

with thc

primary

adrlresses

on

c.tclt 3344

ilrirc

(sec

F-igurcs

2 antl

3).

fior

f rrrthcr elcttrils

on

the

I'irecl

he

ad Icatttrc

arld

its

r.rscl'rtlnt:ss [()

y(lur sl-oragc

rrpplication. c()lltact

\'otlr

f fJM

s;.rlt:s

rcprtsctttativc

()r

sec

lhc

[:i.r'etl

l]ettd

["eulrrrr

I

;.sr

rt

()uir]e.

()rdcr

No.

(iAl6-

l

632.

l.l+o/I1.1-+

Slontqc

(

otIit-ol

lttttl

I titlLttcs

CONFIGURATIONS

'f

he various

configurations

of

3340/3]i44

disk

storage

arc

dividcrl

into

two

groups:

configurati<tns

using

only

3340

units,,

and

configurations

using

a combination

of

3340

and

3344

units.

These

attachmerrt

methods.

listed

by nrodel,

follow.

3340

STORAGE

WITHOUT

3344I

In some

System/370

models,

strings

ol'3330

ancl

3350

storage

devices

can

be uscd

in

addition

to the

3340s.

Model

115

(lISDDA)

Thc

Modcl

I 15 uses

the

Direct

Drive

lr,ttachment

(DDA)

for

storage

control.

Four

drives

can

be

attaclred:

a 3340-A2

dual

drive

with

control.

and

a

3340-82

(dual)

or B I

(single)

drive.

Model

125

(l25DDA)

The

Moclel

125 uses

the

DDA for

stormge

control

ancl

can

ail-ach

one string

of

up to

eight

332f0

drives.

Model 135

(IFA)

The

Model

135

uses

the Integrated

File

Attachment

(lFA)

for storagc

control.

Sixteen

drives,

two

strings.

a

3340 string

and

a string

of

either

3340

or

3333/3330

drivcs

can

be attached.

Models

145,

155-II,

158,

165-II,

and

l6S

(3330-2)

Models

145,

158,

and 168

(ISC)

Storage

control

for

the models

shown

irs

either

a

31330-2

or an

Integrated

Storagc

Control.

The

3830-2

and

each ISC

path

can

attach

up to

32 drives;

four

strings

of

3333/3330s,

3340s, or

3350s in

any

cornbi-

nation.

3340

/

3344

CONFIG

URATIONS

When

the

3344 is

used, neither

3333

/333O

nor

3350

drives can

be attached

to

the same

storage

conl.rol.

A

3344 requires

four

logical

addresses

for

each

drive.

only rhe 135,

145,

155-II, 158,

165-il,

and 168

support

the

3344 dual

drive.

Model

135

(IFA)

The

Model 135

Integratecl

File

Attachment

has

a

maximum

of

34 logical

addresses.

'fhis

allows

two

storage

strings

to

be attached:

a

3340 string

and a

3340/3344

string

(see

Figure 2).

Models

145,

155-II,

158, 165-II,

and 168

(3830-2)

Models 145,

158,

and 168

(ISC)

Sixty-four logical

addresses can

be used

by a

3U30-2

or ISC

path

when a3340/3344

configurarion

is

attached.

Two

strings

of 333O/3344s,

a 3340 string,

and a short

string

of four

3340 drives

can bc

attached.

Figure

3 shows

the maximum334O/3344

configura-

tion.

Only

strings

0 and 2 can incorporate

the

3344

units.

E,ach

drive has

the hexadecimal

addrcsses

assigned

relative

to

the storage

control

as shown.

4

tgll 3l+0,/.1.1

Rcfercncc

Manual

02
1_9

Lq

1C

a3-

1l_

u-

1D

Drive 0 1
No,

String

1

3340-A2

3340-82

3340-82

Drive0

12345

No.

"

Primary Addresses

lrigure

2. IFA 334013344

Maximum Configuration

(Hexadecimal

Adclressing)

3340-82

Drive

No.

01

String

1

3340-A2

01

String

2

3340-A2

3340-82

Drive
No.

Drive

2

3

No.

String

3

3340-A2

3340-82

*

Primary

Addresses

Figure 3.

ISC or

3830-2 |\34013341

Maximum

Configuration

(Hexadecimal

Addressing)

07"
27
2F
37

02*
22
2A

n

19"

1D

39

so

17*

Tr

3B
3F

16*

G

3
3E

10*

20

n

30

11*

n

n

3

18

lts

1A

I

re

Cor.rfigurations

P:rgc

ol'

(i,

\iifr- l o

t

(,

-l

Rcviscd

l\4rr1,

26. l()7(r

Uv

I-Nt,:

(lNl6-0l2l.i

IBM

3348

DATA

MODULIE

DATA n*TODULE

TYPES

'fhe

3340 nroclels uscr thc

IBM

334u Data N,lodulc

as rr

storagc merJiurn.

-f
hree typcs

are avoililble:

the 334lJ

Modcl

35

with

aborrt 35 million

bytes of storaqe" the

33411

Moclcl

70 with about

70 milliorr t'ryies

ol'storage.

ancl the

334l;i

Model

70F

rvith

about

70

rrrillion

bytes

including

one-half million hytes

undcr ifixu-d

hcads.

'fhe

Moclt:ls

35

ancl

70 can be frccly

t:xchangecl

()n

the

-l3rtO clrivcs. but ther Nlclclel

7()[r

can usc its l'ixed heacls

()nlv

on

3-1,10 clrives that l.rave been

convcrtcd I'or

Moclel

70F rr-se

'Ihe

334tJ-lr0F data nrotlule has

tl.re sanrc

char:lcteris-

tir:s as the

3341{-70 cxcept that

r-:f

iinderrs

I thror-rgh

-5

arc acccsscd by

the I'ixed heads. [)ata

r.rn

tracks uncier

thc I'ixed heacis is ar,'ailablc with only rotational

delay.

-fl.rc
othcr

tracks

(cylinders

0 antl {i tlrr,rugh

695) are

suhje

ct to

norrnnl

lreacl access

cle

lays.

Thc thrce rlata
t ii:s:

Bytc

Captcitv

Pr:r imck

Per e

vlinder

Pcr rtt,lilul,:

nrodules have lbe

follt;vrins

charactcris-

DATA

I\T0DUI-T]

INITI ALIZATIII)N

All

l34l{

data rlorlrrlcs arc iniliiilizerl wlr,.lr

nt:rnulac-

trrrcil. llornc

aclclress anrl

l{-bvte

clcscri;rLors

(R0)

lrrc

wriItcrr on

crrch track. If l skipplhlc rl,.'lr:ct

i:i

fourrrl.

tlrc

q'rrttt'n

lrontc

atlclrcss conlains tlrc rtkin rlisplace-

lrcnt hvtc\. [)trrirtg n0rnral

()pcrllti(\ns

tl]e

sl,{)ra!_Ic

conlrol uses thc skip

displacenreltt br.'tc's 1o bypass

llrc

dcicctivc

arca.

Il'a mcrdule data

area bccomes defective cluring normal

usc,

IBN'l

utility

progranrs

are available to flag

dcfcc-

tivc tracks and assign alicrnates

if

required

(DASDI

and AII-AS for

OS

and AL'IDK for DOS).

DATA

ST-JRFACE FORMAT

Thc disk data surface is

dividecl

into

concentric bands

of clata

called tracks

(see

Figure 4). [,ach

datir surface

uses two

rnagnetic

lcad/wr-ite heads. one for

the insicle

irac:ks ancl

one

l'or the clutsictre tracks.

'Ihc

rercording

surlacc o1 the

disk

is

clivicled

in

hall'. All odd num-

bcrecl

l.r;rcks are on one side ol'the divitling Iinc

and all

evern

nunrhere,-'l

trircks are on the o1her. The odd inclex

point

starts

the ocld trac:ks ancl the cven index starts

tire

evcn.

When

thc lreacls are at a

given positior.r,

they

scrvice four

tracks: one odd,

one:

even, one insicle. and

one otrtsiclc.

In

the 334lJ-35 tl:rta nr<ldulc the tracks unclcr the three

outside

heirds ancl those under the three insicle heads

form

a cylinder. All

odd numberrcd tracks

are on one

side of the three

disks arrcl the even

tracks

on the other

sidc. In a

single drive revolution each ht:acl covers tw<r

tracks; one

ocld. and one even.

All

cylinders are

consecrrtively numbered lor a total

of

34it.

I'hi:

-1341{-70

data rnodulc contair.rs four

cltsks. J'he

track

gcomctry

is thc samc as that of the smaller

data

rnoclulc with a cvlindcr irvailablc at cach

position.

Oclcl

numhcred

cylinclers are on thc

uppcr thrce surfaccs

ancl thc

cven

c5,linders are on thc

lower

threc. Fronr a

single

position

lwo

consecutivc

(cven

and odci)

cyliudcrs

can hc

accesscd

1sec

F'igure

5).

The' dii'fcrcricers

he

l-wccn thc storagc mcdia uscd on thc

3340

cluta

st()ritge

units follow:

3348-35 3348-70/70t,

Da(lr

Surfaccs

per

Mcidr"rle 3

(r

2

69(r

2
2

2

t2

24

l2

1

Phvsical lleads ner Surlacc

2

:r348-3s

ii,36l(

l(X).4 l(r

-''il.9d4.7()ll

3348--70/70F

I,368

l(x).416

6'). tt 39.5

3

()

l,.ogicui Cylindr:rs

pcr
A lt rrrr ate
Ci;

l

.ogrcal f-'1,1 inclcrs

pcr

Phvsic:lrl

L-ylindt:r

Physicrii'l'r;rcks

pcr

Plr-vsic:al

Cylincler

l.ogic:rl

-['rai:ks
per

I'hYsical

(--)'Iinder

| .ogicrl I racks

pcr

I ogical

(lvlintlcr

L.ogicnt lrack

pe

r

Physical

'l

rae k

Mocltrle :348

I
I

I

t)

l2
l2

1

(t

llJNl l"t-ll:)/-l.i ltclclcnce Nlanrr;rl

r' l',"

i"

tr,

ta

\.

tt.

t'-\i-.-

i-\i_11_--:-=

=1;1-j,

---

\\

--

--=-__:-_---

./

\ -? ,./-

EVEN TRACK

70

Megabytes

Cylinders
001,003,

005,......699.

(heads

6-1

1

)

Even

lndex

Point

Figure

4.

Data

Surface'frack

l,avorrt

Odd

lndex

Point

)

.,,,nr.,,

\

000,002,

I

oo4,......698.

)

{rreaas

0-s)

Both

Odd

and

Even

Cylinders.

Odd tracks

fo!low

odd index;

even

tracks

follow

even

index.

l"*.

t

n*o'

Odd Cylinders
001,

003.

005,

.......699,

(heads

6-1

1

)

Even

Cylinders
000,002.
004,

......698.

(heads

0-5)

Note:

/n

he

3348-70F data ntodule,

cylinders 001-005

are

located

on the

bottom

surface of the bottont disk.

Figure

5. Data

Module

Ceornetrv

1o,,.

t

'*o'

IBM 3348 Data

Module

FORMATS

RECORD

FORMAT

The basic

unit of information

recorded

by

the drive

is

a byte consisting

of eight

bits.

A

group

of bytes

separated

by a

special

gap

is called

an area.

Areas

are

combined

to make

a record,

the logical

unit

of inform-

ation.

A record

consists

of

count,

key, and

data areas.

Count Area

The

count area

contains

the location

of

a data record

on a

specific track

and defines

the

size of

tlhe key

and

data

areas of the record.

The

count

area is

written

when the

record is formatted

and is not

changed

until

the record is

reformatted.

Key

Area

Use

of

the key area is

at the

discretion

of the

program-

mer. When

used, the key

area of

the record

contains

the

primary

identification

of the

data

portion

of the

record

(such

as social

security number,

man number,

part

number).

Once the key

area is formatted,

the contents

(but

not

the length) may

be altered.

If the key

area

is altered,

the data area

of the record

must also

be rewritten.

Data

Area

The data

area contains

the information

identified

by

the

count and key

areas of the record.

Data informa-

tion is

organized

and arranged

by the

programmer.

The

length

of the data

area is

defined by

the count

area.

Once the data

area is formatted,

the

contents

(but

not

the length)

may be

altered. The

contents

of

the

data area may

be altered

without affecting

any

other

area in the record.

TRACK

FORMAT

All tracks

are initially formatted

beginning

at an index

point

(see

Figure

6).

Each

track has

the

same basic

format:

home

address, track

descriptor

record,

and one

or more data records.

The records.

and areas

within

the

records,

are separated

by

gaps.

Home Address

Each track

contains one home

address, which

defines

the

physical

location

of the track

(track

address)

and

the

condition of

the track. Home address

is the first

recorded area

following

an

index

point.

Specific commands

are used

for

writing and reading

a

home address

area: Write Home Address

and Read

Home

Address. Home

address

is

normally rewritten

to

flag the defective

track. Writing home

addresses is

usually done at

the

IBM

plant.

Track

Descriptor Record

(R0)

This

record is always

the first record on the track

following

the home

address area. In IBM

program-

ming

systems, the R0 count field of

the defective

track

provides

the address of the alternate track.

If it is

an

alternate track,

the

R0

count area

proyides

the

address

of

the defective track. An

8-byte

data field

is used to

store

the

number

of bytes remaining

on the track.

Specific commands, Write R0

and

Read

R0, are used

for

writing and reading the track

descriptor record.

Data Records
One

or more

data records may follow the track

descriptor record

(R0)

on a track. Record format

is

determined at the time the count, key, and

data areas

of the record are

originally written by execution of a

Format Write command.

The format of the record is

rewritten by

another Format Write command.

Data records, as

well as track descriptor records, can

be formatted with or without keys.

Generally, file

organization determines whether keys are

used.

RECORD OVERFLOW
The record overflow

function

provides

a

means

of

processing

logical records that exceed the capacity

of a
track. When using overflow records, the cylinder
boundarv limits the size of the record.

8

IBM

3340144

Reference Manual

Equal length records : 8,535

(track

capacity)

C

+

KL + DL

(bytes/record)

Track : 8,535

>

where:

track

where:

C(overhead/record):

167 if KL

:

0

=242ifKL+0

KL:

Key length

DL: Data length

The number of

records

(n/

of different key

and data

lengths that can be

recorded on a track must

satisfy

the following equation

(the

standard R0 is already

accounted

for):

Records n

Ic

*

KL(i) + DL(i)

i:1

167ifKL:0

242Lt KL

+

O

TRACK

CAPACITY

The number of records that can be recorded on a
track

depends on the record size. The following

equation

can be used to determine the number of

equal

length records

per

track.

The home

address and
standard R0 space and skip defect are taken into
consideration.

When R0 is

not

standard, the

following

formula should

be used:

Records

=8,'706

>-

[KL(o)

+

DL(o)

+

C-4]

+

Track

n

where:

f,

trufil

+

DL(i)

+

cl

i:1

c:167

if

KL:0

c:242if

KL+0

The tables shown in

Figures 7

through l0

give

maxi-

mum sizes of n equal-length

records on

a track where

n

is

all

possible

values.

Track, cylinder, and

data

module capacities

are

given in

both the

number of

bytes and the

number of

records.

There are tables

for records

without keys, and for

records with

keys. In all

tables, overhead for home

address and standard

record

zero

(KL

:

0,

DL : 8)

is

already

accounted

for.

C:
C_

Formats

9

Track

Format

-.-

SD

I

PAIFICCI

HHI

DCB

(syrt.t
J

oata

G3 ( (svste./

/storus.

\Control)

1'Disk

to

]storus.

o'13:lJ"'

I

t0"".

I

I

or""

)

lt

t/

ffi

associated gap.

G2

f-

Ro

c.*,

I

ry

I

G2

I ndex

1\

Lrl

G2

G2

INDEX:

Inclicates

the beginning

of each

trar:k.

All

tracks

on

the

disk

surfar:e

are

synchronized

by

Index.

G1

(Gap

1): Separates

Index

and

Home

Address.

HOME

ADDRESS

SD

(Skip

Displacemer.rt):

Storage

control

indicators

for

skip

displacernent r:oncl

ition

of track.

PA

(Physical

r\dciress):

Storage

control

check for

verification.

Note:

Ihe

SD

artd

PA

bytes are internal

conventiorts

involv-

ing

only

the

storage control

and drive.

The

function

is

transparent

to the

using

systetn.

F

(Flag):

Defines

track condition

as follows:

Bit

0 - Skip

Displacement

Bits

1,2,4,

and 5

--

Unused.

Bits

6 and 7

00 = Normal

Track

01 = Alternate

Track

10=

I

11

|

Defective

Track

The

flag

byte

rray

be transferred

to

and fronn

the using

system. lt rs

tire

only flag

byte transferrable,

CC

(Cylinder

Number):

Specifies

the cylinder

numDer:

For

3348

35

0 to 347

For

3348-70

0 to 695

For

3348 7OF

0 to

695

(cylinders

1-5 fi>red

heads)

HH

(Track

Nurrrber):

Specifies

the readlwrite

track number

with

the selected

cylinder:

For

3348-35

0-1

1

For

3348-70

0-11

For

3348-70F

0-1

1

(cylinders

1-5

fixed

heads)

DCB

(Detection

Code

Bytes):

Generated

by

the 3340-,42

and used

for

error

detection.

l;igurc

6.

Record and

Track

lrornrat

l0

IBM

3340144 Reference

Manual

G2

t

Standard

R0

does

not

contain an R0

key

area

or

G2

(Gap

2):

Separates

home

address

and

R0

counr

area.

RECORD

ZERO

RO

COUNT

AREA

SD and

PA:

Same

as

Home

Address.

F

(Flag):

Defines

track condition

identifier

for

overflow

recoro

s.

Bits

0-2

*

Skip Displacement

Indicators.

Bits

3 and

5 - Unused,

bit 5 is

always

zero.

Bit 4 - When

on, indicates

that a logical

record

continues

on the next

track.

Bits

6 and 7

-

00 = Normal

Track

01

=

Alternate Track

10=

) |

ii=l

DefectiveTrack

CC

(Cylinder

Number):

Specif ies

the cylinder

number:

For

3348-35

0 to 347

For

3348-70

0 to

695

For

3348-70F

0 to 695

(cylinders

1-5 fixed

heads)

HH

(Track

Number): Specifies

the read/write

track

number

within

the selected

cvlinder.

For

3348-35

0-11

For

3348-70

0-1 1

For

3348-70F

0-1

1

(cylinders

1-5 fixed

heads)

R

(Record

Number):

Normally has a value

of Hex

00.

KL

(Key

Length):

Specifies

the number

of bytes in

the R0

key

area, from'0-255

bytes.

For

standard R0.

this

normally

has

a

value

of

Hex

00.

DL

(Data

Length):

Specifies

the

number

of

bytes in

the

R0

data

area,

from

1 to track

capacity.

For

standard R0,

tlris

normally

has a value

of

Hex

08.

DCB

(Detection

Code Bytes):

Generated

by

the 3340-42

and

used

tor

error detection.

Track

Format

Disk

to
Storage
Controi

Data

I

)G3

)

G2

(Gap

2):

Precedes

all key

areas.

RO KEY

AREA

KEY

AREA: ldentifies

information

in

the data

area.

For

standard

R0, this

area is not

present

on the

track.

DCB

(Detection

Code Bytes): lf

key area

is written,

these

bytes are

generated

by the 3340-42

and used for error

detection.

G2

(Gap

2):

Precedes

all data

areas.

RO

DATA AREA

DATA AREA:

Contains

the information

identified

bv

the

count

and

key

areas.

DCB

(Detection

Code

Bytes): Generated

by

the 3340-42

and

used for

error

detection

and correction.

DATA

RECORD

COUNT AREA

(R

1--Rn)

G3

(Gap

3):

Precedes

all

count

areas, except R0,

DATA

RECORD

DATA RECORD

COUNT AREA

F

(Flag):

Same as Record

Zero.

CC

(Cylinder

Number):

Specif ies

the cylinder number:

For

3348-35 0 to

347

For

3348-70 0 to

695

For

3348-70F 0 to

695

(cylinders

|

-5

fixed heads)

I ndex

HH

(Track

Number): Specifies

the

read/write

track

number

within the selected cylinder:

For

3348-35 0-11

For

3348-70

0-11

For

3348-70F

0-1

1

(cylinders

1-5

fixed

heads)

R

(Record

Number):

Specifies

the

sequential number

of

the record

on

the track if

specified by

programmer.

KL

(Key

Length):

Specifies

the number

of bytes in

the

key

area, from

0-255 bytes.

DL

(Data

Length):

Specifies

the number

of bytes in

the

data

area,

from

1 to track capacity.

DCB

(Detection

Code Bytes): Generated

by

the 3340-42

and used for

error

detection.

G2

(Gap

2):

Precedes

all key

areas.

DATA

RECORD

KEY

AREA

(R1-Rn)

KEY AREA: ldentif

ies information

in

the

d,ata area.

DCB

(Detection

Code Bytes): Generated

by

the 3340-42

and used for

error

detection.

G2

(Gap

2):

Precedes

all data

areas.

DATA RECORD

DATA AREA

(R1-Rn)

DATA AREA:

Contains

the information

identified

by

the count

and

key

areas.

DCB

(Detection

Code

Bytes):

Generated

by the 3340-42

and

used for error detection and correction.

G4

{Gap

4): Padding from

end

of the

last data

area to

Index.

lf used for

defect skipping, G4 is cent.ered

over the

defect.

Formats I I

Key DCB

Record

Length

Track

Capacity

Cylinder Capacity

(DL)

(Bytes)

(Records)

(Bytes)

(Records)

(Bytes)

8,368
4,1

00

2,678

1,966
1,540
1,255
1,O52

899
781
686
608
544
489
442
442
366
335
307
282
259
239

220
204

188
174

tol

149

137

't27
't

17

108

99
91
84

76
70

63

57

51
46
41

36

.31

26

22

18
14
10

7
3

1

2

4

5

o

ti
q

10
l1

12

IJ

14

tc
to

17
18

't9
20

21
22
23
24
25
26

27
28
29
30

JI

32

JJ

34
35
36

JI

38
39
40
41
42
43
44
45
46
47
48
49
50

8,368
8,200

8,034

7,864
7,700
7,530
7,364
7,192
7,O29
6,860
6,688
6,528
6,357

6,1 88

6,030

5,856

5,695
5,526
5,358
5,1 80
5,019
4,840
4,692
4,512
4,350
4,186
4,023
3,836

3,683
3,510
3,348
3,1

68
3,003
2,856
2,660
2,520
2,331
2,166

1,989
1,840
1,68i
1,512
1,333
1,144

990
828
658
480
343

150

12
24
36

48

60
72
84
96

108

120

132
144

r56
168
180

192
204
216
228
240
252

264
276
288
300
312
324
336
348
360
372
384
396
408

420

432

444
456
468
480

492

504

516

528

540

552

564

576

588

600

100,416

98,400
96,408
94,368
92,400
90,360
88,368
86,304
84,348

82,320

80,256

78,336
76,284
74,256
72,360
70,272
68,340
66,312
64,296
62,1 60
60,228
58,080
56,304
54,144
52,200
50,232

48,276
46,O32
44,196

42,120

40,176
38,016
36,036

34,272

31,920

30,240

27,972

25,992

23,868

22,O80

20,'t72
't8,144

15.996
13,728

1 1,880

9,936
7,896

5,760

4,116

1,800

Figurc

7.

Rccord

(lapacities

per

Track and

('ylinder

-

Without Keys

12

IBM

3340/44

Reference Manual

MODEL

35

MODEL

7OI7OF

Records

Bytes

Records

Bytes

4,176

8,352
12,528
16,704

20,880
25,056
29,232
33,408
37,584
41,760
45,936
50,112
54,288
58,464
62,640
66,816
70,992
75,1

68
79,344
83,520
87,696
91,872
96,048

100,224
104,400
108,576
1't2,752
116,928
121,104
125,280
129,456
133,632

137.808
14

t

,984

1 46,1

60

150,336
154,512

158.688
162,864
167,O40
171

,216

175,392
179,568
183,744
187,920
192,096
196,272
200,448
204,624
208,800

34,944,768
34,243,200
33,549,984
32,840,064
32,155,200
31,445,280
30,752,064
30,033,792

29.353,1

04
28,647,360
27,929,O88
27,260,928
26,546,832
25,841,O88
25,181,280
24,454,656
23,782,320
23,076,576
22,375,OO8
21,631,680
20,959,344
20,211,840

19,593,792
18,842,112
1

8.165,600
17,480,736
16,800,048
1 6,01 9, 1 36
15,380,208
14,657,760
13,981,248
13,229,568
12,540,528
1 1,926,656
1 1

,1

08,1 60

10,523,520

9,734,256
9,O45,216
8,306,064

7,683,840
7,019,856

6,314,112

5,566,608
4,777,344
4,134,240
3,457,728

2,747,808

2,OO4,480

1,432,368

626,400

8,352

16,704

25,056

33,408

41,760
50,112
58,464

66,816

75,'t68
83,520

91,872
100,224
108,576
1 16,928
125,280
133,632
141,984
150,336
158,688
167,O40
175,392
183,744

't92,096

200,448
208,800
217,152
225,504
233,856
242,208
250,560
258,912
267,264
275,616
283,968
292,320
300,672
309,024
3',t1,376
325,728
334,080
342,432
350,784
359,1

36
367,488
375,840

384,192
392,544
400,896

409,248
4't7,600

69,889,536

68.486,400
67,099,968
65,680,1 28
64,310,400
62,890,560

61,504,128
60,067,584
58,706,208

57,294,720

55.858,1 76
54,521,856
53,093,664
51,682,176
50,362,560
48,909.31 2
47,564,640

46,153,152

44,750,O16
43,263,360
41,918,688

40,423,680
39,187,584
37,684,224
36,331

,200
34,961,472
33,600,096
32,038,272
30,760,416

29,315,520

27,962,496

26,459,136

25,081,056

23,853,312
22,216,320

21,047,O40

19,468,512
18,090,432
16,612,128
15,367,680
14,O39,712
12,628,224
11,133,216

9,554,688

8,268,480
6,915,456
5,495,616
4,008,960
2,864,736

1,252,800

Figurc

8. Record

Capacities

per

Data

Module - Without Keys

Formats

l3

Record

Length

Track

Capacity

Cylinder

Capacity

(KL+DL)

(Bytes)

(Records)

(Bytes) (Recordsl

(Bytes)

8,293
4,O25
2,603

1,891
1,465

't,180

977
824
706
611
533

469

414

367

327
291
260
232
207
184
164
145
129
113

99
86

74

62

52
42
33
24

'16

1
2
3
4
5

o

7
8
9

10
1',|
12
13
14
15

16

17
18

19
20
21
22
23
24
25
26
27
28
29
30
31
32

JJ

34

8,293
8,050
7,809
7,564
7,325

7.080
6,839

6,592
6,354
6,110
5,863
5,628
5,382
5,1 38

4,905

4,656
4,420
4,176

3,933

3,680
3,444
3,1 90

2,967

2,712

2,475

2,236

1,998

1,736

1,508

1,260

1,023

768
528
306

12
24
36
48
60
72
84
96

108
120

132
144
156
168
180
192
204
216
228

240
252
264
276
288
300
312
324
336
348

360
372
384
396
408

99,516
96,600
93,708

90,768

87,900
84,960
82,068
79,104
76,248
73,320

70,356
67,536

64,584
61,656
58,860
55,872
53,040
50,112
47,196
44,160
41,328
38,280
35,604
32,544
29,700
26,832
23,976
20,832
18,096
15,120
12,276

9,216
6,336

3.672

Figurc 9.

Re cord

Capacities

pcr

Track and Cylinder

-

With

Keys

14

IBM

3340144 Reference

Manual

MODEL

35

MODEL

70/7OF

Records

Bytes

Records Bytes

4,176

8,352
12,528
16,704

20,880
25,056
29,232
33,408
37,584
4',t,760
45,936
50,112
54,288
58,464
62,640

oo,b

tb

70,992
75,1

68

79,344
83,520
87,696

91,872
96,048

100,224
104,400
108,576
112,752
1 16,928
121,104
125,280
129,456
133,632
137,808
141,984

34,631,568
33,616,800
32,610,384
31,587,264
30,589,200
29,566,080
28,559,664
27,528,192
26,534,304
25,515,360
24,483,888
23,502,528
22,475,232
21,456,288
20,483,280
19,443,456
18,457,920
17,438,976
16,424,208
15,367,680
14,382,144

't3,321,440
12,390,192

11

,325,312

10,335,600

9,337,536
8,343,648
7,249,536

6,297,408
5,261,760
4,272,048
3,207,168
2,204,928

1,277

,856

8,352

16,704
25,056
33,408
41,760
50,112
58,464
66,816
75,1

68
83,520
91,872

100,224
108,576
116,928
125,280
133,632
141,984
150,336
158,688
167,O40
175,392
183,7 44

r 92,096
200,448
208,800
217

,152

225,504
233,856
242,208
250,560
258,912
267,264
275,616

283,968

69,263,1 36
67,233,600

65,220,768
63,174,528

61

,1

78,400

59, 1 32,1

60
57,119,328
55,056,384
53,068,608
51,O30,120
48,56t,176

47,005,056
44,950,464
42,912,576
40,966,560
38,886,91 2
36,915,840

34,877,952

32,848,416
30,735,360
28,764,288
26,642,880
24,780,384
22,650,624

20,671,200
18,675,072
16,681

,296

14,499,072
12,594,816

10,523,520

8,544,096
6,41

4,336

4,409,856

2,555,712

Iigurc

10. Rccord

('upacitics

per

l)ata Modrrlc Witlt

Ke1,s

Formats

l5