Dell PowerEdge 4400 User Manual

Dell™PowerEdge™4400SystemsUser'sGuide

Reproduction in any manner whatsoever without the written permission of Dell Computer Corporation is strictly forbidden.

Trademarks used in this text: Dell, the DELL logo, Dell OpenManage, and PowerEdge are trademarks and DellWare is a service mark of Dell Computer Corporation; Intel, i960, and Pentium are registered trademarks and MMX, Xeon, and Intel386 are trademarks of Intel Corporation; Microsoft, Windows, MS-DOS, and Windows NT are registered trademarks of Microsoft Corporation; Novell and NetWare are registered trademarks of Novell, Inc.; ASPI is a registered trademark of Adaptec, Inc.; VESA is a registered trademark and VL-Bus is a trademark of Video Electronics Standards Association; Adobe is a trademark of Adobe Systems Incorporated, which may be registered in certain jurisdictions; OS/2 is a registered trademark of International Business Machines, Inc.

Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. Dell Computer Corporation disclaims any proprietary interest in trademarks and trade names other than its own.

Initial release: 10 Sep 1999 Last revised: 4 Nov 1999

Safety Instructions

Preface

Introduction

Using the Dell OpenManage Server Assistant CD

Installing and Configuring SCSI Drivers

Using the System Setup Program

Using the Resource Configuration Utility

Technical Specifications

I/O Ports and Connectors

Maintaining the System

Regulatory Notices

Warranty, Return Policy, and Year 2000 Statement of Compliance

Glossary

Model SML

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Using the Dell OpenManage Server AssistantCD:Dell™PowerEdge4400Systems User's Guide

Overview

The Dell OpenManage Server Assistant CD contains utilities, diagnostics, documentation, drivers, and other items that can help you configure a PowerEdge 4400 system to best meet your needs. Some of the functions available on the Dell OpenManage Server Assistant CD are also available on a bootable utility partition that is installed on your hard-disk drive. This section describes how to use the Dell OpenManage Server Assistant CD. It also describes the utility partition and its options and provides instructions for reinstalling the partition (if necessary).

Starting the Dell OpenManage Server Assistant CD

The Dell OpenManage Server Assistant application program has two modes of operation: a setup mode for setting up and configuring the PowerEdge4400system,creatingdiskettes,andviewinginformationanddocuments,andaservice mode for creating diskettes and viewing information and documents.

In both setup mode and service mode, the Dell OpenManage Server Assistant main page gives you the option to choose one of the supported languages as the language for the screen text and online documentation. You can choose a language at any time from the main screen.

Setup Mode

To setup your system, as well as access the utilities, drivers, and other items available on the Dell OpenManage Server Assistant CD, insert the Dell OpenManage Server Assistant CD into your CD-ROM drive, and turn on or reboot the system. The Dell OpenManage Server Assistant

main page appears. If the CD does not boot, verify that the Boot Device Priority must be set to CD-ROM Drive in the System Setup program. See "Using the System Setup Program" for more information.

Service Mode

You can access the online system documents, system setup instructions, frequently asked questions, and server product information on any desktop or server system that has Microsoft®Internet Explorer 4.0 (or later). When you insert the CD in a system that uses the Microsoft Windows NT®operating system, the system automatically starts the browser software and displays the Dell OpenManage Server Assistant main page.

Navigating the CD

The Dell OpenManage Server Assistant CD utilizes a standard Web browser interface. To navigate the CD, click the mouse on the various icons and text hyperlinks.

Click the Back icon to return to the previous page. Click the Exit icon to exit the program. Exiting the program causes the system to reboot to the standard operating-system boot partition.

Using the Setup Modes

If you purchase a system that does not have an operating system preinstalled by Dell, or if you reinstall an operating system at a later date, you should use either the Express Setup or Custom Setup option to configure your system.

Express Setup

Dell recommends Express Setup for most situations. The Dell OpenManage Server Assistant CD guides you through the operating system setup and configuration process. If a Dell PowerEdge Expandable RAID Controller (PERC) host adapter is installed, the Dell redundant arrays of independent disks (RAID) utility configures the drives. If the drive does not have a utility partition, one is created. The program prompts you to select the operating system used on the drive and leads you through a step-by-step process to install the operating system.

To start Express Setup, perform the following steps:

Overview

Utility Partition

Starting the Dell OpenManage Server Assistant CD

Video Driver

Navigating the CD

Asset Tag Utility

Using the Setup Modes

1. Click the SETUP icon at the top of the screen.

2. Click Express Setup.

3. Follow the directions on the screen to complete the installation and configuration.

Express Setup allows you to perform the following tasks:

l Create the Express Setup diskette l Enter operating system and hard-disk drive information l Configure the operating system l Perform setup

Custom Setup

Use Custom Setup if your system has special configuration requirements. To start Custom Setup, perform the following steps:

1. Click the SETUP icon at the top of the screen.

2. Click Custom Setup.

3. Follow the directions on the screen to complete the installation and configuration.

Utility Partition

The utility partition is a bootable partition on the hard-disk drive that provides some of the functions available on the Dell OpenManage Server Assistant CD. Most of the application programs found on the CD are contained in the utility partition. When implemented, the partition boots and

provides an executable environment for the partition's utilities. When the utility partition is not booted, it is designated as a non–MS-DOS® partition.

To start the utility partition, turn on or reboot the system. During the power-on self-test (POST), the following message appears:

Press <F10> to enter Utility Mode

The utility partition provides a text-based interface from which you invoke the partition's utilities. Menu options and the associated help are displayed in the currently selected language (specified via a menu option). To select a menu option, you can either use the arrow keys to highlight the option and press <Enter>, or type the number of the menu option. To return to the previous menu, press <Esc> or select the Back menu option. To exit the utility partition, press <Esc> from the Main Menu. Exiting the utility from setup mode causes the system to reboot to the standard operating-system boot partition.

Table 1 provides a sample list and explanation of the options that appear on the utility partition menu even when the Dell OpenManage Server

Assistant CD is not in the CD-ROM drive. The options displayed on your system may vary depending on the configuration.

Table 1.UtilityPartitionMainMenuOptions

NOTE: The utility partition provides only limited MS-DOS functionality and cannot be used as a general-purpose MS-DOS partition.

NOTE: Although most options are available from both the Dell OpenManage Server Assistant CD and the utility partition, some options or features, such as those for accessing online documentation, are available only from the CD.

Option

Description

Choose a Language:

German,English,Spanish,French

Allows you to select the language in which menus and messages are displayed. Run System and Configuration Utilities:

Run Resource Configuration Utility

Runs the RCU.

Run Dell System Diagnostics

Runs the system hardware diagnostics.

Run RAID Configuration Utility

Runs the RAID controller configuration utility if a RAID controller card is present on your system.

Running the System Diagnostics

You can run the system diagnostics from the utility partition or from a diskette, but not from the Dell OpenManage Server Assistant CD. To run the diagnostics from a diskette, create a diagnostics diskette from the the Dell OpenManage Server Assistant CD.

The system hardware diagnostics are described in "Running the Dell Diagnostics" in the Dell PowerEdge 4400 Systems Installation and Troubleshooting Guide.

Video Driver

You need to install the video driver for the operating system you install on your system unless they were installed by Dell.

InstallingVideoDriversforWindowsNTServer4.0

First, create a driver diskette by performing the following steps:

1. Select Create Diskettes from the Dell OpenManage Server Assistant setup page.

2. Select the system for which to create the driver diskette.

3. Create the video-controller driver diskette for Windows NT 4.0.

Then install the video driver by performing the following steps:

1. Start Windows NT.

2. Log in as the administrator or as a user with administrative privileges. For information on system administration, see the reference documentation for Windows NT.

3. Click the Start button, point to Settings, and click Control Panel.

4. Double-click the Display icon. The Display Settings window appears.

Create Diskettes:

Create Blank, Formatted diskette

Creates a blank, formatted diskette.

Create Utility and Diagnostics diskettes:

Create Resource Configuration Utility diskettes

Creates a bootable diskette for running the RCU. The RCU detects expansion cards and slots, enabling automatic configuration.

Create PERC 2 Configuration Utility diskette

Creates a bootable diskette for running the RAID controller configuration utility for the specified Dell RAID host adapter card. The RAID configuration utility provides an alternative method for configuring the card.

Create Diagnostics diskettes

Creates a set of diskettes from which the hardware diagnostics can be run. The first diskette in the set is bootable.

Create Asset Tag diskette with CD-ROM

Creates a bootable diskette with CD-ROM support from which utilities, such as the Asset Tag utility, can be run.

NOTES: The options displayed on your system are dependent on your system configuration and may not include all of those listed here. For the full name of an abbreviation or acronym used in this table, see the "Glossary."

NOTES: The video display for the Microsoft Windows NT Server 4.0 operating system must be set up with a resolution of 640 x 480 at installation.

Windows NT Server 4.0 Service Pack 4 must be installed before you can use the updated video driver for the ATI Rage video controller.

NOTE:VideodriversmustbereinstalledaftereveryinstallationofWindowsNTServer4.0ServicePack3(orlaterversions).Usethis

procedure only if you do not use Express Setup to install your operating system.

5. Select the Settings tab.

6. Click Display Type and then click Change in the Adapter box. A list of available video drivers is displayed.

7. Click Have Disk.

8. Insert the video driver installation diskette into the diskette drive; then click OK in the Install From Disk window.

9. Make sure that ATI Rage IIc (the default) is selected in the video driver list, and click Install. The Installing Drivers dialog box appears.

10. Click Yes to proceed. After the files are copied from the diskette, Windows NT prompts you to restart your system. Click OK and close all open windows.

11. RemovethevideodriversdiskettefromthediskettedriveandrestartWindowsNT.

12. Click the Start button, point to Settings, and click Control Panel.

13. Click the Display icon. The Display Settings window appears.

14. Set the desired resolution, number of colors, and refresh rate.

Asset Tag Utility

The Asset Tag utility allows you to enter an asset tag number for your system.

Using the Asset Tag Utility

To create the Asset Tag utility diskette and boot the system, perform the following steps:

1. If you have not already done so, create a bootable Asset Tag utility diskette from the Dell OpenManage Server Assistant CD using the Create Asset Tag diskette with CD-ROM option.

2. Insert the diskette into the diskette drive and reboot the system.

After you boot the system with the Asset Tag utility diskette, you can use the Asset Tag utility to enter an asset tag number that you or your organization assigns to the system. You can also use the Asset Tag utility to reenter the system's service tag number if that becomes necessary.

Assigning and Deleting an Asset Tag Number

An asset tag number can have up to ten characters; any combination of characters, excluding spaces, is valid. To assign or change an asset tag number, perform the following steps:

1. Perform the steps in "Using the Asset Tag Utility."

2. Type asset and a space followed by the new number.

3. Press <Enter>. For example, type the following command line and press <Enter>:

asset 1234567890

4. When you are prompted to verify the asset tag number, type y and press <Enter>. The system then displays the new or modified asset tag number and the service tag number.

To delete the asset tag number without assigning a new one, type asset /d and press <Enter>. Table 2 lists the command-line options you can use with the Asset Tag utility. To use one of these options, type asset and a space followed by

the option.

NOTE: The Asset Tag utility works only on systems running MS-DOS.

NOTE: The Asset Tag utility diskette contains CD-ROM drivers that provide access to the CD-ROM drive when you boot from the diskette.

Table 2. Asset Tag Command-Line Options

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Asset Tag Option

Description

Deletes the asset tag number

Displays the Asset Tag utility help screen

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Using the Resource Configuration Utility: Dell™PowerEdge™4400SystemsUser's Guide

Overview

The Resource Configuration Utility (RCU) is used to tell the system what expansion cards are installed and which expansion slots they occupy. With this information, the system automatically configures Plug and Play expansion cards and Peripheral Component Interconnect (PCI) expansion cards. Before your system was shipped from Dell, a technician used the RCU to enter the correct information for the expansion cards initially installed in your computer.

The RCU also monitors the resources required by any installed PCI expansion card. After installing or moving a PCI expansion card, you should run the RCU to update the system's database of available system resources stored in nonvolatile random-access memory (NVRAM).

NOTICE: Whenever you make changes to the System Setup program or change settings for integrated devices, you must run the RCU, make any necessary changes, and save the system configuration information. Failure to do so may cause resource conflicts between PCI devices (such as PCI expansion cards, the integrated video controller, or the integrated small computer system interface [SCSI] host adapter). See "Configuring Expansion Cards" for more information about how PCI devices are configured based on settings in the RCU.

Configuring Expansion Cards

The RCU is PCI-aware and can also be used to configure PCI expansion cards. Configuration information for PCI expansion cards is contained within the card, so no additional .cfg file is required. You should run the RCU after installing or moving a PCI expansion card to keep the system's database of available resources accurate.

How to Run the RCU

The RCU is included on the Dell OpenManage Server Assistant CD shipped with your system. This CD includes an RCU directory that contains the main program.

You can run the RCU directly from the CD or from a diskette that you create using the CD's main menu. Dell recommends that you run the RCU from a diskette because the RCU is not compatible with all operating systems. Also, using a diskette to run the utility allows you to copy any system configuration changes to the diskette for safekeeping. See "Using the Dell OpenManage Server Assistant CD" for instructions on creating an RCU diskette.

PCI expansion cards do not require a configuration file. The PCI configuration utility in ROM automatically uses the information maintained by the RCU to assign resources for PCI expansion cards.

When to Run the RCU

Whenever you add or remove expansion cards, you must run the RCU to ensure that no two cards attempt to use the same resources (such as interrupt request [IRQ] lines).

After you have run the RCU and it has configured all your expansion cards, you can use the utility to lock the configuration of your PCI expansion cards so that they are always assigned the same resources.

Making Selections in the RCU

The RCU uses menus to guide you through the configuration process. The menus and their options are accessed through keyboard commands. To make a menu selection, press the up- or down-arrow key to highlight the desired option, and then press <Enter>. In the Help menu or

Advanced menu, you can also select an option by pressing the key that corresponds to the highlighted letter in the selection list. To scroll up or down a screen, press the <Page Up> or <Page Down> key, respectively.

Using Online Instructions

The RCU has online instructions for each of its procedures. If you need help at any time, press <F1> to see a help screen that offers more details about the task you are doing.

Overview

Advanced Menu

Starting the RCU

Resolving Resource Conflicts

Main Menu

NOTE: If your system detects a card configuration problem during operation, you receive a warning message directing you to run the RCU to correct the problem.

Starting the RCU

If you are running the RCU from your hard-disk drive, remove any terminate-and-stay-resident (TSR) programs from memory before starting the utility. These programs take up space in system memory even when they are not running, thus reducing the amount of memory available to the RCU. See the documentation that accompanied these programs for instructions on removing them from memory.

If you start the utility and there is not enough memory to run it, a message is displayed. If you receive such a message, run the utility from a diskette. Perform the following steps the first time you use the RCU. Later, if a card is added, removed, or repositioned, you must follow the procedure

described in "Step 2: Add or Remove Boards."

1. To run the program from a diskette, insert the RCU diskette that you created from the CD into drive A. Then either turn on your computer or reboot it by pressing the <Ctrl><Alt><Del> key combination or the reset button.

To run the program from your hard-disk drive, switch to the c:\rcu subdirectory, type sd at the operating system prompt, and press <Enter>. To run the program from the Dell OpenManage Server Assistant CD, restart the system from the CD. Select Run RCU from the CD's main

menu.

2. When the Welcome screen appears, read the information on the screen and press <Enter>. The Main Menu appears:

Main Menu Learn about configuring your computer

Configure computer Set date Set time Maintain system configuration diskette Exit from this utility

The first option in the menu is already highlighted.

3. Press <Enter> to read the online overview of the RCU. After reading the online overview, you are ready to use the program to configure your computer for any PCI expansion cards currently

installed.

Main Menu

The following sections describe each of the menu options in the Main Menu and the submenus for those options.

Learn About Configuring Your Computer

The Learn about configuring your computer option presents an overview of the configuration process. As you finish reading a screen, press <Enter> to view the next screen. Press <F10> to return to the Main Menu.

Configure Computer

The Configure computer option takes you through the configuration process step by step. Use this option the first time you configure your system and every time you change your configuration through the RCU.

When you select Configure computer, the following menu appears on the screen:

Steps in configuring your computer

Step 1: Important resource configuration information Step 2: Add or remove boards Step 3: View or edit details Step 4: Examine switches or print report Step 5: Save and exit

Step 1: Important Resource Configuration Information

The Step 1: Important resource configuration information option uses seven information screens to explain the configuration process. After you read the first screen, press <Enter> to see the next one. When you finish reading all seven screens, press <Esc> to return to the Steps in configuring your computer menu.

To review the information screens at any time while you are in the RCU, press <F1> and select Resource Configuration from the Help menu.

Step 2: Add or Remove Boards

When you select the Step 2: Add or remove boards option, the RCU lists all the expansion slots in your computer. (You may have to press <Page Down> to view the entire list.)

If you copied a card's configuration file to your RCU diskette or to the RCU configuration subdirectory (rcu) on your hard-disk drive, the card name appears in the expansion slot in which the card is installed.

The first time you run the RCU, select Step 2: Add or remove boards to verify that the system has detected and acknowledged any expansion cards Dell installed when you purchased your system. Use this option whenever you add or remove an expansion card and every time you reposition a card from one expansion slot to another in your computer.

To add, reposition, or remove an expansion card, highlight the corresponding expansion slot and press <Ins> to add, <F7> to reposition, or <Del> to remove the card. The utility guides you through the steps required to add, reposition, or remove a card's configuration file within the RCU. If there are no resource conflicts, the system configuration information is saved to a system configuration (.sci) file when you exit the utility.

Repositioning an Expansion Card

Use the following procedure after a PCI expansion card is repositioned. See "When to Run the Resource Configuration Utility" for more detailed information.

1. Start the RCU.

2. At the Main Menu, select Configure computer.

3. At the Steps in configuring your computer menu, select Step 2: Add or remove boards. A list of expansion slots and the cards in them appears on the screen.

4. Highlight the name of the card that you want to reposition, press <F7>, and follow the online instructions.

5. Press <F10>, select Step 5: Save and exit, and follow the online instructions to save the current system configuration information. Remember to save a printout or written copy of the new information.

Removing an Expansion Card

Perform the following steps after you remove a PCI expansion card. See "When to Run the Resource Configuration Utility" for more detailed information.

1. Start the RCU.

2. At the Main Menu, select Configure computer.

3. At the Steps in configuring your computer menu, select Step 2: Add or remove boards. A list of expansion slots and the cards installed in them appears on the screen.

4. Highlight the name of the card you want to remove, press <Del>, and follow the online instructions.

If there are no resource conflicts, the configuration information is saved to a system configuration (.sci) file when you exit the utility. If there is a resource conflict, you must resolve it before completing the configuration.

Step 3: View or Edit Details

The RCU lets you set a variety of system options through the .sci file. Through this file, you can notify the system of changes to your hardware and memory configuration, manage input/output (I/O) ports, and set other system operating parameters.

Some of the categories do not offer options, but reflect installed hardware that is detected by the system. These items are displayed for your information only; you cannot change them through the utility.

To display the list of system board options, perform the following steps:

1. Start the RCU.

2. At the Main Menu, select Configure computer.

3. At the Steps in configuring your computer menu, select Step 3: View or edit details. A list of system board options appears on the screen. Figure 1 shows settings typical for your system.

4. To select a category on the list of system board options, press the up- or down-arrow key to highlight the category and press <Enter>.

NOTE: Whenever you add an expansion card to the computer, its presence is reflected by changes to the System Board Options screen.

A pop-up menu appears, listing the options for that category. To select an option, press the up- or down-arrow key to highlight the option and press <Enter>.

When you have finished making changes, perform the following steps to save the new system configuration information and exit the utility:

1. Press <F10>, and select Step 5: Save and exit from the Steps in configuring your computer menu.

2. Select Save the configuration and restart the computer from the menu that appears.

Figure 1 shows the system board options that are available on the View or edit details screen.

Figure 1. View or Edit Details Screen (Example)

Step 4: Examine Switches or Print Report

The Step 4: Examine switches or print report option lists the required switch and jumper settings for each expansion card in your computer. To view the settings, highlight the card and press <Enter>.

Press <F7> to make a copy of or print the settings. If your computer is attached to a printer, you can print the information or copy it to a file.

Step 5: Save and Exit

The Step 5: Save and exit option allows you to save or cancel the configuration changes that you have made. When you select this option, follow the directions on the menu that displays.

Ifyousaveyourchanges,theutilitysavesthenewconfigurationinyoursystem'sNVRAMandinafileonyourRCUdiskette.Theutilityautomatically

reboots your system. If you cancel your changes, you can remain in the utility to make other changes or exit the utility without saving any changes.

Maintain System Configuration Diskette

Using the Maintain system configuration diskette option, you can create a backup copy of the .sci file or use a previously saved .sci file to reconfigure your system or to identically configure many other systems. You can also copy .cfg files and delete .sci and .cfg files from your RCU diskette, your diskette of .cfg files, or the configuration diskette(s) for any hardware option.

NOTES: Several system board categories allow you to edit such resources as memory address, I/O ports, IRQs, and direct memory access (DMA) channels. It may be necessary to edit these resources to resolve a configuration conflict. To view the resource screen for any category, highlight the option and press <F6>.

The edit resources feature is intended for users who are technically knowledgeable. Do not change resource settings from their defaults if you do not understand how such a change will affect system performance.

While in the Step 3: View or edit details menu, you can press <F7> to enter the Advancedmenu.

Exit From This Utility The Exit from this utility option allows you to exit from the RCU and reboot your computer system.

Advanced Menu

The Advanced menu lets you lock or unlock cards in a configuration, view detailed information about the system, and maintain .sci files. To see the Advanced menu, press <F7> while in the Step 3: View or edit details menu. The following menu appears:

Advanced menu Lock/unlock boards

View additional system information menu Set verification mode menu Maintain SCI files menu

Highlight the menu category that you want and press <Enter>. Then follow the online instructions. The following subsections describe each category.

Lock/Unlock Boards

When you lock an expansion card, the RCU cannot change the resources allocated to that card. Unlocking the card allows the system to change the resources automatically as new cards are added. The default setting for the Lock/unlock boards category is Unlocked. Dell recommends that you keep your cards unlocked so that the RCU can do its job properly.

View Additional System Information Menu The RCU contains detailed information about the system board and the used and available resources. The options for the View additional

system information menu category are:

l Board Specifications l System Specifications l Used Resources l Available Resources

The Used Resources and Available Resources options contain detailed information about resources such as IRQs, DMA channels, and I/O ports, which may be useful if you need to resolve a resource conflict.

Set Verification Mode Menu

The settings for the Set verification mode menu category are Automatic (the default) and Manual. When this category is set to Automatic, the RCU automatically checks for resource conflicts and tries to resolve them. Unless you are technically knowledgeable, leave this category set to

Automatic.

Maintain SCI Files Menu

Each time you use the RCU to configure your system, the system configuration information is saved in a .sci file and in system memory. You should save the system configuration information to a backup file that can be used to restore the information if the .sci file is damaged or lost. The options for the Maintain SCI files menu category are Open (the default) and Save As.

The Open option creates a backup file that overwrites the existing configuration. The Save As option allows you to select the filename under which you want the .sci file saved.

Resolving Resource Conflicts

The RCU automatically resolves resource conflicts between PCI expansion cards. It is extremely unusual for the RCU to fail in resolving a resource conflict between two PCI expansion cards. If the RCU fails to resolve the conflict, see "Getting Help" in your Installation and Troubleshooting Guide for information on obtaining technical assistance.

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NOTE: The RCU ignores the Lock/unlock boards setting for the PCI host bridge and the PCI-to-PCIbridgedevices.

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Glossary:Dell™PowerEdge™4400SystemsUser'sGuide

A •B •C •D •E •F •G •H •I •J •K •L •M •N •O •P •Q •R •S •T •U •V •W • X •Y •Z

The following list defines or identifies technical terms, abbreviations, and acronyms used in Dell user documents.

A

Abbreviation for ampere(s).

Abbreviation for alternating current.

adapter card

An expansion card that plugs into an expansion-card connector on the computer's system board. An adapter card adds some specialized function to the computer by providing an interface between the expansion bus and a peripheral device. Examples of adapter cards include network cards, sound boards, and SCSI adapters.

ADC

Abbreviation for analog-to-digital converter.

ADI

Abbreviation for Autodesk Device Interface.

Abbreviation for artificial intelligence.

ANSI

Acronym for American National Standards Institute.

application program

Software designed to help you perform a specific task, such as a spreadsheet or word processor. Application programs are distinct from operating system and utility software.

ASCII

Acronym for American Standard Code for Information Interchange. A text file containing only characters from the ASCII character set (usually created with a text editor, such as MS-DOS®Editor or Notepad in Microsoft®Windows®operating system) is called an ASCII file.

ASIC

Acronym for application-specific integrated circuit.

ASPI®

Acronym for Advanced SCSI programming interface. autoexec.bat file When you boot your computer, MS-DOS runs any commands contained in the text file, autoexec.bat (after running any commands in the

config.sys file). An autoexec.bat file is not required to boot MS-DOS, but provides a convenient place to run commands that are essential for setting up a consistent computing environment—such as loading mouse or network software.

B

backup

A copy of a program or data file. As a precaution, you should back up your computer's hard-disk drive on a regular basis. Before making a change

to the configuration of your computer, you should back up important start-up files, such as autoexec.bat and config.sys for MS-DOS or win.ini and system.ini for Microsoft Windows.

base memory

Synonym for conventional memory.

BASIC

Acronym for Beginner's All-Purpose Symbolic Instruction Code, a programming language. MS-DOS includes a version of BASIC.

batch file

An ASCII text file containing a list of commands that run in sequence. Batch files must have a filename extension of .bat.

baud rate

Data transmission speed. For example, modems are designed to transmit data at one or more specified baud rate(s) through the COM (serial) port of a computer.

BBS

Abbreviation for bulletin board service. A computer system that serves as a central location for accessing data or relaying messages by modem. For example, Dell's TechConnect BBS contains the latest version of software such as video drivers and the Dell Directory. If your system has a modem, you can access the BBS and download the most recent version of this software.

beep code

A diagnostic system message in the form of a series of beeps from your computer's speaker. See your Installation and Troubleshooting Guide for a complete discussion of system beep codes.

BIOS

Acronym for basic input/output system. Your computer's BIOS contains programs stored on a ROM chip. The BIOS controls the following functions:

l Communications between the microprocessor and peripheral devices such as the keyboard and the video adapter l Miscellaneous functions, such as system messages

bit

The smallest unit of information interpreted by your computer.

block

A typical unit of disk storage consisting of a small number of sectors. This term usually refers to the fundamental unit of storage provided by an operating system. See also block size and striping.

block size

The size of a block. See also block and striping.

boot routine

When you start your computer, it clears all memory, initializes devices, and loads the operating system. Unless the operating system fails to respond, you can reboot (also called warm boot) your computer by pressing <Ctrl><Alt><Del>; otherwise, you must perform a cold boot by pressing the reset button (if your computer has one) or by turning the computer off and then back on.

bootable diskette

You can start your computer from a diskette in drive A. To make a bootable diskette, insert a diskette in drive A, type sys a: at the command line prompt and then press <Enter>. Use this bootable diskette if your computer will not boot from the hard-disk drive.

bpi

Abbreviation for bits per inch.

bps

Abbreviation for bits per second.

BTU

Abbreviation for British thermal unit.

bus

A bus forms an information pathway between the components of a computer. Your computer contains an expansion bus that allows the microprocessor to communicate with controllers for all the various peripheral devices connected to the computer. Your computer also contains an address bus and a data bus for communications between the microprocessor and RAM.

byte

Eight contiguous bits of information; the basic data unit used by your computer.

BZT

Abbreviation for Bundesamt fur Zulassungen in deer Telecommunication.

C

Abbreviation for Celsius.

cache

To facilitate quicker data retrieval, a storage area for keeping a copy of data or instructions. For example, your computer's BIOS may cache ROM code in faster RAM. Or a disk-cache utility may reserve RAM in which to store frequently accessed information from your computer's disk drives; when a program makes a request to a disk drive for data that is in the cache, the disk-cache utility can retrieve the data from RAM faster than from the disk drive.

card-edge connector

On the bottom of an expansion card, the metal-contact section that plugs into an expansion-card connector.

CCFT

Abbreviation for cold cathode fluorescent tube.

CD-ROM

Abbreviation for compact disc read-only memory. CD-ROM drives use optical technology to read data from compact discs. CDs are read-only storage devices; you cannot write new data to a CD with standard CD-ROM drives.

CGA

Abbreviation for color graphics adapter.

CIO

Abbreviation for comprehensive input/output.

Abbreviation for centimeter(s).

CMOS

Acronym for complementary metal-oxide semiconductor. In computers, CMOS memory chips are often used for NVRAM storage.

COM

The MS-DOS device names for the first through fourth serial ports on your computer are COM1, COM2, COM3, and COM4. MS-DOS supports up to four serial ports. However, the default interrupt for COM1 and COM3 is IRQ4, and the default interrupt for COM2 and COM4 is IRQ3. Therefore, you must be careful when you configure software that runs a serial device so that you do not create an interrupt conflict.

CON

The MS-DOS device name for the console, which includes your computer's keyboard and text displayed on the screen.

config.sys file

When you boot your computer, MS-DOS runs any commands contained in the text file config.sys (before running any commands in the autoexec.bat file). A config.sys file is not required to boot MS-DOS, but provides a convenient place to run commands that are essential for

setting up a consistent computing environment—such as loading device drivers with a device= statement.

controller

A chip or expansion card that controls the transfer of data between the microprocessor and a peripheral such as a diskette drive or the keyboard.

conventional memory

The first 640 KB of RAM. Unless they are specially designed, MS-DOS programs are limited to running in conventional memory. See also EMM,

expanded memory, extended memory, HMA, memory manager, upper memory area, and XMM.

coprocessor

A coprocessor relieves the computer's microprocessor of specific processing tasks. A math coprocessor, for example, handles numeric processing. A graphics coprocessor handles video rendering. The Intel®Pentium®microprocessor includes an integrated math coprocessor.

cpi

Abbreviation for characters per inch.

CPU

Abbreviation for central processing unit. See also microprocessor.

cursor

In character-based MS-DOS programs, the cursor is usually a block or an underscore (possibly blinking) that represents the position at which the next character typed will appear. Windows programs can design their own cursors—common cursor symbols include the pointer arrow and the text-insertion I-beam.

D

DAC

Acronym for digital-to-analog converter.

DAT

Acronym for digital audio tape.

Abbreviation for decibel(s).

dBA

Abbreviation for adjusted decibel(s).

Abbreviation for direct current.

DDC

Acronym for display data channel. A VESA®standard mechanism that allows the system to communicate with the monitor and retrieve information about its capabilities.

device driver

A device driver allows the operating system or a program to interface correctly with a peripheral such as a printer or network card. Some device drivers—such as network drivers—must be loaded from the config.sys file (with a device= statement) or as memory-resident programs (usually, from the autoexec.bat file). Others—such as video drivers—must load when you start the program for which they were designed.

DHCP

Acronym for Dynamic Host Configuration Protocol.

diagnostics

See diskette-based diagnostics.

DIMM

Acronym for dual in-line memory module.

DIN

Acronym for Deutsche Industrie Norm.

DIP

Acronym for dual in-line package. A circuit board, such as a system board or expansion card, may contain DIP switches for configuring the circuit board. DIP switches are always toggle switches, with an ON position and an OFF position.

directory

Directories help keep related files organized in a hierarchical, "inverted tree" structure. Each disk has a "root" directory; for example, a C:\> prompt normally indicates that you are at the root directory of hard-disk drive C. Additional directories that branch off of the root directory are called subdirectories. Subdirectories may contain additional directories branching off of them.

diskette-based diagnostics

A comprehensive set of diagnostic tests for your Dell computer. To use the diskette-based diagnostics, you must boot your computer from the Dell Diagnostics Diskette. Refer to your Installation and Troubleshooting Guide for a complete discussion about how to use the diskette-based

diagnostics.

display adapter

See video adapter.

DMA

Abbreviation for direct memory access. A DMA channel allows certain types of data transfer between RAM and a device to bypass the microprocessor.

DOC

Abbreviation for Department of Communications (in Canada).

dpi

Abbreviation for dots per inch.

DPMS

Abbreviation for Display Power Management Signaling. A standard developed by the Video Electronics Standards Association that defines the hardware signals sent by a video controller to activate power management states in a video display or monitor. A monitor is said to be DPMScompliant when it is designed to enter a power management state after receiving the appropriate signal from a computer's video controller.

DRAC

AcronymforDellOpenManage™RemoteAssistantCard.

DRAM

Abbreviation for dynamic random-access memory. A computer's RAM is usually made up entirely of DRAM chips. Because DRAM chips cannot store an electrical charge indefinitely, your computer continually refreshes each DRAM chip in the computer.

drive-type number

Your computer can recognize a number of specific hard-disk drives. Each is assigned a drive-type number that is stored in NVRAM. The hard-disk drive(s) specified in your computer's System Setup program must match the actual drive(s) installed in the computer. The System Setup program also allows you to specify physical parameters (cylinders, heads, write precomp, landing zone, and capacity) for drives not included in the table of drive types stored in NVRAM.

DS/DD

Abbreviation for double-sided/double-density.

DS/HD

Abbreviation for double-sided/high-density.

DTE

Abbreviation for data terminal equipment. Any device (such as a computer system) that can send data in digital form by means of a cable or communications line. The DTE is connected to the cable or communications line through a data communications equipment (DCE) device such as a modem.

E

ECC

Abbreviation for error checking and correction.

ECP

Abbreviation for Extended Capabilities Port.

EDO

Abbreviation for extended-data out. A type of RAM chip that holds data on the chip's output data lines for a longer period of time than fast-page mode RAM chips. The EDO RAM chips are also faster than fast-page mode RAM chips.

EEPROM

Acronym for electrically erasable programmable read-only memory.

EGA

Abbreviation for enhanced graphics adapter.

EISA

Acronym for Extended Industry-Standard Architecture, a 32-bit expansion-bus design. The expansion-card connectors in an EISA computer are also compatible with 8- or 16-bit ISA expansion cards.

To avoid a configuration conflict when installing an EISA expansion card, you must use the EISA Configuration Utility. This utility allows you to specify which expansion slot contains the card and obtains information about the card's required system resources from a corresponding EISA configuration file.

EMC

Abbreviation for Electromagnetic Compatibility.

EMI

Abbreviation for electromagnetic interference.

EMM

Abbreviation for expanded memory manager. A software utility that uses extended memory to emulate expanded memory on computers with an

Intel386™orhighermicroprocessor.Seealsoconventional memory, expanded memory, extended memory, memory manager, and XMM.

EMP

Abbreviation for emergency management port.

EMS

Abbreviation for Expanded Memory Specification. See also expanded memory, memory manager, and XMS.

EPROM

Acronym for erasable programmable read-only memory.

ESD

Abbreviation for electrostatic discharge. See "Safety Instructions" for a complete discussion of ESD.

ESDI

Acronym for enhanced small-device interface.

expanded memory

A technique for accessing RAM above 1 MB. To enable expanded memory on your computer, you must use an EMM. You should configure your system to support expanded memory only if you run application programs that can use (or require) expanded memory. See also conventional

memory, EMM, extended memory, and memory manager.

expansion bus

Your computer contains an expansion bus that allows the microprocessor to communicate with controllers for peripheral devices, such as a network card or an internal modem.

expansion-card connector

A connector on the computer's system board for plugging in an expansion card.

extended memory

RAM above 1 MB. Most software that can use it, such as Windows, requires that extended memory be under the control of an XMM. See also

conventional memory, expanded memory, memory manager, and XMM.

external cache memory

A RAM cache using SRAM chips. Because SRAM chips operate at several times the speed of DRAM chips, the microprocessor can retrieve data and instructions faster from external cache memory than from RAM.

F

Abbreviation for Fahrenheit.

FAT

Acronym for file allocation table. The file system structure used by MS-DOS to organize and keep track of file storage. The Microsoft Windows NT®operating system can optionally use a FAT file system structure.

FCC

Abbreviation for Federal Communications Commission.

flash memory

A type of EEPROM chip that can be reprogrammed from a utility on diskette while still installed in a computer; most EEPROM chips can only be rewritten with special programming equipment.

format

To prepare a hard-disk drive or diskette for storing files. An unconditional format deletes all data stored on the disk. The format command in MSDOS 5.0 or higher includes an option that allows you to unformat a disk if you have not yet used the disk for file storage.

Abbreviation for foot/feet.

FTP

Abbreviation for file transfer protocol.

G

Abbreviation for gram(s).

Abbreviation for gravities.

Abbreviation for gigabyte(s). A gigabyte equals 1024 megabytes or 1,073,741,824 bytes.

graphics coprocessor

See coprocessor.

graphics mode

See video mode.

guarding

A type of data redundancy that uses a set of physical drives to store data and a single, additional drive to store parity data. Data is protected from the loss of a single drive. Guarding is sometimes preferred over mirroring because it is more cost-effective in systems with a very high storage capacity. However, guarded configurations are significantly slower for applications that frequently write to the array, because each attempt to write to the array requires multiple read and write commands to maintain the parity information. If this is a problem, mirroring or duplexing is a better choice. See also mirroring, RAID 4, and RAID 5.

GUI

Acronym for graphical user interface.

H

Abbreviation for hexadecimal. A base-16 numbering system, often used in programming to identify addresses in the computer's RAM and I/O memory addresses for devices. The sequence of decimal numbers from 0 through 16, for example, is expressed in hexadecimal notation as: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10. In text, hexadecimal numbers are often followed by h or preceded by 0x. MS-DOS conventional memory— the first 640 KB of memory addresses—is from 00000h to 9FFFFh; the MS-DOS upper memory area—memory addresses between 640 KB and 1 MB—is from A0000h to FFFFFh.

heat sink

A metal plate with metal pegs or ribs that help dissipate heat. Some microprocessors include a heat sink.

HMA

Abbreviation for high memory area. The first 64 KB of extended memory above 1 MB. A memory manager that conforms to the XMS can make the HMA a direct extension of conventional memory. See also conventional memory, memory manager, upper memory area, and XMM.

host adapter

A host adapter implements communication between the computer's bus and the controller for a peripheral. (Hard-disk drive controller subsystems include integrated host adapter circuitry.) To add a SCSI expansion bus to your system, you must install the appropriate host adapter.

HPFS

Abbreviation for the High Performance File System option in the Windows NT operating system.

Abbreviation for hertz.

I

I20

Abbreviation for intelligent input/output.

Abbreviation for integrated circuit.

ICMB

Abbreviation for inter-chassis management bus.

I/O

Abbreviation for input/output. The keyboard and a printer, for example, are I/O devices. In general, I/O activity can be differentiated from computational activity. For example, when a program sends a document to the printer, it is engaging in I/O activity; when the program sorts a list of terms, it is engaging in computational activity.

Abbreviation for identification.

interlacing

A technique for increasing video resolution by only updating alternate horizontal lines on the screen. Because interlacing can result in noticeable screen flicker, most users prefer noninterlaced video adapter resolutions.

internal microprocessor cache

An instruction and data cache built into the microprocessor. The Pentium microprocessor, for example, includes a 16-KB internal cache, which is set up as an 8-KB read-only instruction cache and an 8-KB read/write data cache.

Acronym for Internet Protocol.

IPX

Abbreviation for Internetwork Packet eXchange.

IRQ

Abbreviation for interrupt request. A signal that data is about to be sent to or received by a peripheral travels by an IRQ line to the microprocessor. Each peripheral connection must be assigned an IRQ number. For example, the first serial port in your computer (COM1) is assigned to IRQ4 by default. Two devices can share the same IRQ assignment, but you cannot operate both devices simultaneously.

IRTOS

Abbreviation for I2O real-time operating system.

ISA

Acronym for Industry-Standard Architecture. A 16-bit expansion bus design. The expansion-card connectors in an ISA computer are also compatible with 8-bit ISA expansion cards.

ITE

Abbreviation for information technology equipment.

J

JEIDA

Acronym for Japanese Electronic Industry Development Association.

K

Abbreviation for kilo-, indicating 1000.

Abbreviation for kilobyte(s), 1024 bytes.

KB/sec

Abbreviation for kilobyte(s) per second.

Kbit(s)

Abbreviation for kilobit(s), 1024 bits.

Kbps

Abbreviation for kilobit(s) per second.

key combination

A command requiring that you press multiple keys at the same time. For example, you can reboot your computer by pressing the <Ctrl><Alt><Del> key combination.

Abbreviation for kilogram(s), 1000 grams.

kHz

Abbreviation for kilohertz, 1000 hertz.

L

LAN

Acronym for local area network. A LAN system is usually confined to the same building or a few nearby buildings, with all equipment linked by wiring dedicated specifically to the LAN.

Abbreviation for pound(s).

LCD

Abbreviation for liquid crystal display. A low-power display often used for notebook computers. An LCD consists of a liquid crystal solution between two sheets of polarizing material. An electric current causes each crystal to act like a shutter that can open to allow light past or close to block the light.

LED

Abbreviation for light-emitting diode. An electronic device that lights up when a current is passed through it.

LIF

Acronym for low insertion force. Some computers use LIF sockets and connectors to allow devices such as the microprocessor chip to be installed or removed with minimal stress to the device.

Abbreviation for load number.

local bus

On a computer with local-bus expansion capability, certain peripheral devices (such as the video adapter circuitry) can be designed to run much faster than they would with a traditional expansion bus. Some local-bus designs allow peripherals to run at the same speed and with the samewidth data path as the computer's microprocessor.

LPTn

The MS-DOS device names for the first through third parallel printer ports on your computer are LPT1, LPT2, and LPT3.

LUN

Acronym for logical unit number.

M

Abbreviation for meter(s).

Abbreviation for milliampere(s).

mAh

Abbreviation for milliampere-hour(s).

math coprocessor

See coprocessor.

Abbreviation for megabyte(s). The term megabyte means 1,048,576 bytes; however, when referring to hard-disk drive storage, the term is often rounded to mean 1,000,000 bytes.

MBR

Abbreviation for master boot record.

MDA

Abbreviation for monochrome display adapter.

memory

A computer can contain several different forms of memory, such as RAM, ROM, and video memory. Frequently, the word memory is used as a synonym for RAM; for example, an unqualified statement such as "a computer with 8 MB of memory" refers to a computer with 8 MB of RAM.

memory address

A specific location, usually expressed as a hexadecimal number, in the computer's RAM.

memory manager

A utility that controls the implementation of memory in addition to conventional memory, such as extended or expanded memory. See also

conventional memory, EMM, expanded memory, extended memory, HMA, upper memory area, and XMM.

MGA

Abbreviation for monochrome graphics adapter.

MHz

Abbreviation for megahertz.

microprocessor

Because it is the primary computational chip inside the computer, it is customary to refer to the microprocessor as "the computer's brain." The microprocessor contains an arithmetic processing unit and a control unit. Software written for one microprocessor must usually be revised to run on another microprocessor. CPU is a synonym for microprocessor.

min

Abbreviation for minute(s).

mirroring

A type of data redundancy that uses a set of physical drives to store data and one or more sets of additional drives to store duplicate copies of the data. Mirroring is the preferred data redundancy technique in lower-capacity systems and in systems where performance is extremely important. See also guarding, RAID 1, and RAID 10.

Abbreviation for millimeter(s).

mouse

A pointing device that controls the movement of the cursor on a screen. Mouse-aware software allows you to activate commands by clicking a mouse button while pointing at objects displayed on the screen.

MPS

Abbreviation for multiprocessing specification.

Abbreviation for millisecond(s).

MS-DOS

Abbreviation for Microsoft Disk Operating System.

MTBF

Abbreviation for mean time between failures.

multifrequency monitor

A monitor that supports several video standards. A multifrequency monitor can adjust to the frequency range of the signal from a variety of video adapters.

Abbreviation for millivolt(s).

N

NIC

Acronym for network interface controller.

NiCad

Acronym for nickel cadmium.

NiMH

Abbreviation for nickel-metal hydride.

NLM

Acronym for NetWare®Loadable Module.

NMI

Abbreviation for nonmaskable interrupt. A device sends an NMI to signal the microprocessor about hardware errors such as parity errors.

noninterlaced

A technique for decreasing screen flicker by sequentially refreshing each horizontal line on the screen.

Abbreviation for nanosecond(s), one billionth of a second.

NTFS

Abbreviation for the NT File System option in the Windows NT operating system.

NVRAM

Abbreviation for nonvolatile random-access memory. Memory that does not lose its contents when you turn off your computer. NVRAM is used for maintaining the date, time, and system setup options.

O

OS/2®

Abbreviation for Operating System/2.

OTP

Abbreviation for one-time programmable.

P

parallel port

An I/O port used most often to connect a parallel printer to your computer. You can usually identify a parallel port on your computer by its 25-hole connector.

parameter

A value or option that you specify to a program. A parameter is sometimes called a switch or an argument.

partition

You can divide a hard-disk drive into multiple physical sections called partitions with the fdisk command. Each partition can contain multiple logical drives. For example, you could partition a 2-GB hard-disk drive into two physically separate partitions with three logical drive assignments, as shown in the following table.

After partitioning the hard-disk drive, you must format each logical drive with the format command.

PC Card

Slightly larger than a credit card, a PC Card is a removable I/O card—such as a modem, LAN, SRAM, or flash memory card—that adheres to the PCMCIA standards. See also PCMCIA.

PCI

Abbreviation for Peripheral Component Interconnect. A standard for local-bus implementation developed by Intel Corporation.

PCMCIA

Abbreviation for Personal Computer Memory Card International Association. See also PC Card.

PDC

Acronym for primary domain controller.

PERC

Acronym for PowerEdge Expandable RAID controller.

peripheral device

An internal or external device—such as a printer, a disk drive, or a keyboard—connected to a computer.

PGA

Abbreviation for pin grid array, a type of microprocessor socket that allows you to remove the microprocessor chip.

pixel

Arranged in rows and columns, a pixel is a single point on a video display. Video resolution—640 x 480, for example—is expressed as the number of pixels across by the number of pixels up and down.

POST

Acronym for power-on self-test. Before the operating system loads when you turn on your computer, the POST tests various system components such as RAM, the disk drives, and the keyboard.

ppm

Abbreviation for pages per minute.

PQFP

Abbreviation for plastic quad flat pack, a type of microprocessor socket in which the microprocessor chip is permanently mounted.

program diskette set

Partitioning the Hard-Disk Drive

Physical Partitions and Sizes

Partition 1 - 1.2 GB / Partition 2 - 800 MB

Logical Drive Assignments and Sizes

Drive C - 1.2 GB / Drive D - 500 MB / Drive E - 300 MB

The set of diskettes from which you can perform a complete installation of an application program. When you reconfigure a program, you often need its program diskette set.

protected mode

An operating mode supported by 80286 or higher microprocessors, protected mode allows operating systems to implement:

l A memory address space of 16 MB (80286 microprocessor) to 4 GB (Intel386 or higher microprocessor) l Multitasking l Virtual memory, a method for increasing addressable memory by using the hard-disk drive

The Windows NT 32-bit operating system runs in protected mode. MS-DOS cannot run in protected mode; however, some programs that you can start from MS-DOS—such as Windows—are able to put the computer into protected mode.

PS/2

Abbreviation for Personal System/2.

PSPB

Abbreviation for power-supply paralleling board.

PVC

Abbreviation for polyvinyl chloride.

Q

QIC

Abbreviation for quarter-inch cartridge.

R

RAID

Acronym for redundant arrays of independent disks. This phrase was introduced by David Patterson, Garth Gibson, and Randy Katz at the University of California at Berkeley in 1987. The goal of RAID is to use multiple small, inexpensive disk drives to provide high storage capacity and performance while maintaining or improving the reliability of the disk subsystem.

Patterson, Gibson, and Katz described five different methods, which are known as RAID levels 1 through 5. Each level uses one or more extra drives to provide a means of recovering data lost when a disk fails, so that the effective failure rate of the whole disk subsystem becomes very low.

RAID 0

RAID 0 is commonly called striping. This was not originally defined as a RAID level but has since come into popular use. In this array configuration, data is written sequentially across the available disks and no redundancy is provided. RAID 0 configurations provide very high performance but relatively low reliability. RAID 0 is the best choice when controller cards are duplexed. See also striping.

RAID 1

RAID 1 is commonly called mirroring. RAID 1 also uses striping, so RAID 1 may be regarded as the mirroring of RAID 0 configurations. RAID 1 is the best choice in high-availability applications that require high performance or relatively low data capacity. See also mirroring, RAID 10, striping.

RAID 4

RAID 4 is commonly called guarding. It uses data striping, like RAID 0, but adds a single, dedicated parity drive. The parity data stored on this drive can be used to recover data lost from a single failed drive. RAID 4 configurations write data slowly because parity data has to be generated and written to the parity drive, and the generation of the parity data frequently requires reading data from multiple physical drives. See also

guarding and striping.

RAID 5

RAID 5, like RAID 4, is commonly called guarding. RAID 5 is identical to RAID 4, except that the parity data is distributed evenly across all physical drives instead of a parity drive. In configurations using a large number of physical drives in which a large number of simultaneous small write operations are being performed, RAID 5 offers potentially higher performance than RAID 4. RAID 4 and RAID 5 configurations are appropriate in high-availability applications where performance is less critical or where high data capacity is required. See also guarding.

RAID 10

RAID 10 is a mirroring technique in which data is duplicated across two identical RAID 0 arrays or hard-disk drives. All data on a physical drive in one array is duplicated, or mirrored, on a drive in the second array. Mirroring offers complete redundancy of data for greater data security. See also mirroring, RAID 1, and striping.

RAM

Acronym for random-access memory. The computer's primary temporary storage area for program instructions and data. Each location in RAM is identified by a number called a memory address. Any information stored in RAM is lost when you turn off your computer.

RAMDAC

Acronym for random-access memory digital-to-analog converter.

RCA

Acronym for Resource Configuration Add-in.

RCU

Acronym for Resource Configuration Utility.

read-only file

A read-only file is one that you are prohibited from editing or deleting. A file can have read-only status if:

l Its read-only attribute is enabled. l It resides on a physically write-protected diskette. l It is located on a network in a directory to which the system administrator has assigned read-only rights to you.

real mode

An operating mode supported by 80286 or higher microprocessors, real mode imitates the architecture of an 8086 microprocessor. Designed to run in real mode, MS-DOS (unassisted by additional software techniques) can address only 640 KB of conventional memory.

refresh rate

The frequency, measured in Hz, at which the screen's horizontal lines are recharged. A monitor's refresh rate is also referred to as its vertical frequency.

REN

Abbreviation for ringer equivalence number.

RFI

Abbreviation for radio frequency interference.

RGB

Abbreviation for red/green/blue.

ROM

Acronym for read-only memory. Your computer contains some programs essential to its operation in ROM code. Unlike RAM, a ROM chip retains its contents even after you turn off your computer. Examples of code in ROM include the program that initiates your computer's boot routine and the POST.

rpm

Abbreviation for revolutions per minute.

RTC

Abbreviation for real-time clock. Battery-powered clock circuitry inside the computer that keeps the date and time after you turn off the computer.

S

SCSI

Acronym for small computer system interface. An I/O bus interface with faster data transmission rates than standard ports. You can connect up to seven devices to one SCSI interface.

SDMS

Abbreviation for SCSI device management system.

SDRAM

Abbreviation for synchronous dynamic random-access memory.

SDS

Abbreviation for scalable disk system.

SEC

Abbreviation for single-edge contact.

sec

Abbreviation for second(s).

sector

The fundamental unit of data access for a hard-disk drive. For PC-compatible systems, a sector is usually 512 bytes. See also block and block

size.

serial port

An I/O port used most often to connect a modem or a mouse to your computer. You can usually identify a serial port on your computer by its 9-pin connector.

SIMD

Acronym for single instruction, multiple data.

shadowing

A computer's system and video BIOS code is usually stored on ROM chips. Shadowing refers to the performance-enhancement technique that copies BIOS code to faster RAM chips in the upper memory area (above 640 KB) during the boot routine.

SMART

Acronym for Self-Monitoring Analysis and Reporting Technology. A technology that allows hard-disk drives to report errors and failures to the system BIOS, which then displays an error message on the screen. To take advantage of this technology, you must have a SMART-compliant hard-disk drive and the proper support in the system BIOS.

SMB

Abbreviation for system management bus.

SMP

Abbreviation for symmetric multiprocessing.

SNMP

Abbreviation for Simple Network Management Protocol.

striping

In composite drivers with two or more physical drives, the drive array subsystem uses a method of data storage called striping. With this method, data is divided into a series of pieces called blocks and each data block is stored on a different physical drive. When each drive contains a block of data, the process starts over with the first physical drive. When the size of the data block is carefully selected, the chance that the information needed can be read from or written to multiple physical drives at once is increased, greatly increasing the performance of the composite drive. See also block, block size, and RAID.

SRAM

Abbreviation for static random-access memory. Because SRAM chips do not require continual refreshing, they are substantially faster than DRAM chips. SRAM is used mostly for external cache memory.

SVGA

Abbreviation for super video graphics array. See also VGA.

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