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Computer Software

Information and help with Microsoft DOS

MS-DOS OVERVIEW

Below is a listing of each of the MS-DOS commands currently listed on Computer Hope and a brief explanation of what each of the commands do. The below commands are all MS-DOS commands, which means not all the below commands will work in your version of MS-DOS / Windows. Clicking on the command will open the help page for that command.

COMMAND DESCRIPTION

ANSI.SYS Defines functions that change display graphics, control cursor movement, and reassign keys.

APPEND Causes MS-DOS to look in other directories when editing a file or running a command.

ARP Displays, adds, and removes arp information from network devices.

ASSIGN Assign a drive letter to an alternate letter.

ASSOC View the file associations.

AT Schedule a time to execute commands or programs.

ATMADM Lists connections and addresses seen by Windows ATM call manager.

ATTRIB Display and change file attributes.

BATCH Recovery console command that executes a series of commands in a file.

BOOTCFG Recovery console command that allows a user to view, modify, and rebuild the boot.ini

BREAK Enable / disable CTRL + C feature.

CACLS View and modify file ACL's.

CALL Calls a batch file from another batch file.

CD Changes directories.

CHCP Supplement the International keyboard and character set information.

CHDIR Changes directories.

CHKDSK Check the hard disk drive running FAT for errors.

CHKNTFS Check the hard disk drive running NTFS for errors.

CHOICE Specify a listing of multiple options within a batch file.

CLS Clears the screen.

CMD Opens the command interpreter.

COLOR Easily change the foreground and background color of the MS-DOS window.

COMMAND Opens the command interpreter.

COMP Compares files.

COMPACT Compresses and uncompress files.

CONTROL Open Control Panel icons from the MS-DOS prompt.

CONVERT Convert FAT to NTFS.

COPY Copy one or more files to an alternate location.

CTTY Change the computers input/output devices.

DATE View or change the systems date.

DEBUG Debug utility to create assembly programs to modify hardware settings.

DEFRAG Re-arrange the hard disk drive to help with loading programs.

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DEL Deletes one or more files.

DELETE Recovery console command that deletes a file.

DELTREE Deletes one or more files and/or directories.

DIR List the contents of one or more directory.

DISABLE Recovery console command that disables Windows system services or drivers.

DISKCOMP Compare a disk with another disk.

DISKCOPY Copy the contents of one disk and place them on another disk.

DOSKEY Command to view and execute commands that have been run in the past.

DOSSHELL A GUI to help with early MS-DOS users.

DRIVPARM Enables overwrite of original device drivers.

ECHO Displays messages and enables and disables echo.

EDIT View and edit files.

EDLIN View and edit files.

EMM386 Load extended Memory Manager.

ENABLE Recovery console command to enable a disable service or driver.

ENDLOCAL Stops the localization of the environment changes enabled by the setlocal command.

ERASE Erase files from computer.

EXIT Exit from the command interpreter.

EXPAND Expand a Microsoft Windows file back to it's original format.

EXTRACT Extract files from the Microsoft Windows cabinets.

FASTHELP Displays a listing of MS-DOS commands and information about them.

FC Compare files.

FDISK Utility used to create partitions on the hard disk drive.

FIND Search for text within a file.

FINDSTR Searches for a string of text within a file.

FIXBOOT Writes a new boot sector.

FIXMBR Writes a new boot record to a disk drive.

FOR Boolean used in batch files.

FORMAT Command to erase and prepare a disk drive.

FTP Command to connect and operate on a FTP server.

FTYPE Displays or modifies file types used in file extension associations.

GOTO Moves a batch file to a specific label or location.

GRAFTABL Show extended characters in graphics mode.

HELP Display a listing of commands and brief explanation.

IF Allows for batch files to perform conditional processing.

IFSHLP.SYS 32-bit file manager.

IPCONFIG Network command to view network adapter settings and assigned values.

KEYB Change layout of keyboard.

LABEL Change the label of a disk drive.

LH Load a device driver in to high memory.

LISTSVC Recovery console command that displays the services and drivers.

LOADFIX Load a program above the first 64k.

LOADHIGH Load a device driver in to high memory.

LOCK Lock the hard disk drive.

LOGON Recovery console command to list installations and enable administrator login.

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MAP Displays the device name of a drive.

MD Command to create a new directory.

MEM Display memory on system.

MKDIR Command to create a new directory.

MODE Modify the port or display settings.

MORE Display one page at a time.

MOVE Move one or more files from one directory to another directory.

MSAV Early Microsoft Virus scanner.

MSD Diagnostics utility.

MSCDEX Utility used to load and provide access to the CD-ROM.

NBTSTAT Displays protocol statistics and current TCP/IP connections using NBT

NET Update, fix, or view the network or network settings

NETSH Configure dynamic and static network information from MS-DOS.

NETSTAT Display the TCP/IP network protocol statistics and information.

NLSFUNC Load country specific information.

NSLOOKUP Look up an IP address of a domain or host on a network.

PATH View and modify the computers path location.

PATHPING View and locate locations of network latency.

PAUSE Command used in batch files to stop the processing of a command.

PING Test / send information to another network computer or network device.

POPD Changes to the directory or network path stored by the pushd command.

POWER Conserve power with computer portables.

PRINT Prints data to a printer port.

PROMPT View and change the MS-DOS prompt.

PUSHD Stores a directory or network path in memory so it can be returned to at any time.

QBASIC Open the QBasic.

RD Removes an empty directory.

REN Renames a file or directory.

RENAME Renames a file or directory.

RMDIR Removes an empty directory.

ROUTE View and configure windows network route tables.

RUNAS Enables a user to execute a program on another computer.

SCANDISK Run the scandisk utility.

SCANREG Scan registry and recover registry from errors.

SET Change one variable or string to another.

SETLOCAL Enables local environments to be changed without affecting anything else.

SETVER Change MS-DOS version to trick older MS-DOS programs.

SHARE Installs support for file sharing and locking capabilities.

SHIFT Changes the position of replaceable parameters in a batch program.

SHUTDOWN

Shutdown the computer from the MS-DOS prompt.

SMARTDRV Create a disk cache in conventional memory or extended memory.

SORT Sorts the input and displays the output to the screen.

START Start a separate window in Windows from the MS-DOS prompt.

SUBST Substitute a folder on your computer for another drive letter.

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SWITCHES Remove add functions from MS-DOS.

SYS Transfer system files to disk drive.

TELNET Telnet to another computer / device from the prompt.

TIME View or modify the system time.

TITLE Change the title of their MS-DOS window.

TRACERT Visually view a network packets route across a network.

TREE View a visual tree of the hard disk drive.

TYPE Display the contents of a file.

UNDELETE Undelete a file that has been deleted.

UNFORMAT Unformat a hard disk drive.

UNLOCK Unlock a disk drive.

VER Display the version information.

VERIFY Enables or disables the feature to determine if files have been written properly.

VOL Displays the volume information about the designated drive.

XCOPY Copy multiple files, directories, and/or drives from one location to another.

MS-DOS

Listing of secret and/or unknown MS-DOS commands and options.

Below is a listing of MS-DOS commands that are not listed in any available help manual or in the commands syntax or are commonly unknown commands. Many of these commands that are known can be very useful when using MS-DOS, while some of the other commands are unknown and/or appear to do nothing.

Please use these commands cautiously, some of the commands can erase data and/or erase data without warning.

ATTRIB , The command is short for ATTRIB -a -h -r - s *.* (removes all attributes of a file).

BACKUP /HP Unknown

DIR , This lists all files including hidden files, does not work in Windows 95 / 98 / NT / 2000.

DIR ... Lists all directories that do not have extensions. In Windows 95 / Windows 98 will list the contents of the directories previous to the directory currently in.

DOSKEY /APPEDIT

Utilize doskey functions in MS-DOS command utilities such as edlin and debug.

DOSKEY /COMMAND

Unknown

DOSKEY /PERMANENT

Unknown

DOSKEY /SCRSIZE Unknown

DOSKEY Unknown

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/XHISTORY

FDISK /MBR Recreates the Master Boot Record See CH000175 for additional information.

FDISK /PRI See FDISK Page for additional information.

FDISK /EXT See FDISK Page for additional information.

FDISK /LOG See FDISK Page for additional information.

FDISK /Q Prevents fdisk from booting the system automatically after exiting fdisk.

FDISK /STATUS Shows you the current status of your hard drives.

FORMAT /AUTOTEST

Formats the hard drive without any prompting.

FORMAT /BACKUP

Like /AUTOTEST but it will ask you for a volume label.

FORMAT /Z:n Command used with FDISK supporting FAT32, used to specify the cluster size in bytes where n is multiplied by 512.

MEM /A or /ALL Adds a line into the MEM command tells the available space in HMA.

RESTORE /Y Unknown

RESTORE /Z Unknown

SET DIRCMD=0 Will make all directories hidden however still accessible, to get them back SET DIRCMD=

SHARE /NC Unknown

TRUENAME When placed before a file, will display the whole directory in which it exists.

VER /R Tells you the Revision and if DOS is in HMA.

Computer Hardware

PC Compatible memory diagram.

Below is is an illustration of the four sections of memory. All of the below specifications are conclusive for all IBM compatible computers.

XMS Remainder of all Memory above 1MB except

the first 640KB

External memory (XMS) - directly accessible memory starting at 1 MB requires HIMEM.SYS as an external memory manager (loaded in config.sys) 80386 Limited to 16 MB

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80286 Limited to 8 MB

XMS Definition

HMA First 64KB of memory Beyond 1MB

High memory area (HMA) - first 64 KB of XMS also requires HIMEM.SYS as an external memory manager (loaded in config.sys) Only 1 program at a time can access HMA Commonly used for loading DOS "high", but also used for TSRs.

HMA Definition

UMB 384KB

Upper memory area (UMA) is located between 640KB and 1MB. Contains the ROM BIOS, device controller ROM, and video controller ROM and RAM

UMB Definition

CONVENTIONAL 640KB

(This is static and will never change no matter how much ram you have in the

computer.

Conventional memory - traditionally was the only memory available to DOS It contains devices drivers, conventional variables, the DOS command Processor, TSRs application programs, an data.

Conventional Memory definition

DOS APPLICATIONS

Below is a listing of the applications included with MS-DOS and the type of file extension it was. As MS-DOS continued to grow, applications were removed and added. In this list you can see which programs were included with your versions of MS-DOS. This list only applies for MS-DOS 2.x to 6.22. As Windows grew into what it is today, many of the applications were removed or changed. If you're running Windows 95 or higher and want to know if an application is available, see the command page for that application or command.

Command Versions

2.0x 2.1x 3.00 3.1x 3.3x 4.0x 5.0 6.0 6.2 6.21

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3.2x 5.00a 6.22

APPEND N/A N/A N/A EXE EXE EXE EXE EXE EXE EXE

ASSIGN COM COM COM COM COM COM COM N/A N/A N/A

ATTRIB N/A N/A EXE EXE EXE EXE EXE EXE EXE EXE

BACKUP COM COM COM COM COM COM EXE N/A N/A N/A

BASIC COM COM COM COM N/A N/A N/A N/A N/A N/A

BASICA COM COM COM COM N/A N/A N/A N/A N/A N/A

CHKDSK COM COM COM COM COM COM EXE EXE EXE EXE

CHOICE N/A N/A N/A N/A N/A N/A N/A COM COM COM

COMMAND COM COM COM COM COM COM COM COM COM COM

COMP COM COM COM COM COM COM EXE N/A N/A N/A

DBLSPACE N/A N/A N/A N/A N/A N/A N/A EXE EXE N/A

DEBUG COM COM COM COM COM COM EXE EXE EXE EXE

DEFRAG N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

DELTREE N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

DISKCOMP COM COM COM COM COM COM COM COM COM COM

DISKCOPY COM COM COM COM COM COM COM COM COM COM

DOSKEY N/A N/A N/A N/A N/A N/A COM COM COM COM

DOSSHELL N/A N/A N/A N/A N/A COM COM EXE N/A N/A

DOSSWAP N/A N/A N/A N/A N/A N/A EXE EXE N/A N/A

DRVSPACE N/A N/A N/A N/A N/A N/A N/A N/A N/A EXE

EDIT N/A N/A N/A N/A N/A N/A COM COM COM COM

EDLIN COM COM COM COM COM COM EXE N/A N/A N/A

EMM386 N/A N/A N/A N/A N/A N/A EXE EXE EXE EXE

EXE2BIN N/A EXE EXE EXE EXE EXE EXE N/A N/A N/A

EXPAND N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

FASTHELP N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

FASTOPEN N/A N/A N/A N/A EXE EXE EXE EXE EXE EXE

FC N/A N/A N/A N/A EXE EXE EXE EXE EXE EXE

FDISK COM COM COM COM COM EXE EXE EXE EXE EXE

FILESYS N/A N/A N/A N/A N/A EXE N/A N/A N/A N/A

FIND EXE EXE EXE EXE EXE EXE EXE EXE EXE EXE

FORMAT COM COM COM COM COM COM COM COM COM COM

GRAFTABL N/A N/A COM COM COM COM COM N/A N/A N/A

GRAPHICS COM COM COM COM COM COM COM COM COM COM

GWBASIC N/A N/A N/A N/A EXE EXE N/A N/A N/A N/A

HELP N/A N/A N/A N/A N/A N/A EXE COM COM COM

IFSFUNC N/A N/A N/A N/A N/A EXE N/A N/A N/A N/A

INTERLNK N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

INTERSVR N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

JOIN N/A N/A N/A EXE EXE EXE EXE N/A N/A N/A

KEYB N/A N/A N/A N/A COM COM COM COM COM COM

KEYBFR N/A N/A COM COM N/A N/A N/A N/A N/A N/A

KEYBGR N/A N/A COM COM N/A N/A N/A N/A N/A N/A

KEYBIT N/A N/A COM COM N/A N/A N/A N/A N/A N/A

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KEYBSP N/A N/A COM COM N/A N/A N/A N/A N/A N/A

KEYBUK N/A N/A COM COM N/A N/A N/A N/A N/A N/A

LABEL N/A N/A COM COM COM COM EXE EXE EXE EXE

LINK EXE EXE EXE EXE EXE EXE N/A N/A N/A N/A

LOADFIX N/A N/A N/A N/A N/A N/A COM COM COM COM

MEM N/A N/A N/A N/A N/A EXE EXE EXE EXE EXE

MEMMAKER N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MIRROR N/A N/A N/A N/A N/A N/A COM N/A N/A N/A

MODE COM COM COM COM COM COM COM COM COM COM

MORE COM COM COM COM COM COM COM COM COM COM

MOVE N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MSBACKUP N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MSCDEX N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MSD N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MWAV N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MWAVTSR N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MWBACKUP N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

MWUNDEL N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

NLSFUNC N/A N/A N/A N/A EXE EXE EXE EXE EXE EXE

POWER N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

PRINT COM COM COM COM COM COM EXE EXE EXE EXE

QBASIC N/A N/A N/A N/A N/A N/A EXE EXE EXE EXE

RECOVER COM COM COM COM COM COM EXE N/A N/A N/A

REPLACE N/A N/A EXE N/A EXE EXE EXE EXE EXE EXE

RESTORE COM COM COM COM COM COM EXE EXE EXE EXE

SCANDISK N/A N/A N/A N/A N/A N/A N/A N/A EXE EXE

SELECT N/A N/A COM COM COM COM N/A N/A N/A N/A

SETVER N/A N/A N/A N/A N/A N/A EXE EXE EXE EXE

SHARE N/A N/A EXE EXE EXE EXE EXE EXE EXE EXE

SIZER N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

SMARTDRV N/A N/A N/A N/A N/A N/A N/A EXE EXE EXE

SMARTMON N/A N/A N/A N/A N/A N/A N/A EXE EXE N/A

SORT EXE EXE EXE EXE EXE EXE EXE EXE EXE EXE

SUBST N/A N/A N/A EXE EXE EXE EXE EXE EXE EXE

SYS COM COM COM COM COM COM COM COM COM COM

TREE COM COM COM COM COM COM COM COM COM COM

UNDELETE N/A N/A N/A N/A N/A N/A EXE EXE EXE EXE

UNFORMAT N/A N/A N/A N/A N/A N/A COM COM COM COM

VSAFE N/A N/A N/A N/A N/A N/A N/A COM COM COM

XCOPY N/A N/A N/A N/A EXE EXE EXE EXE EXE EXE

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Computer Software

Information about the autoexec.bat and the config.sys.

QUICK LINKS

About the autoexec / config How to edit the files Remarking information Getting additional memory Autoexec.bat layout Config.sys layout Information about batch files Technical support

ABOUT THE AUTOEXEC / CONFIG

The autoexec.bat and the config.sys were files created for MS-DOS and Windows 3.x as an easy solution of loading the files required for various devices as well as the operating system to properly run. These files are required for later revisions of MS-DOS and Windows 3.x to load. Because Microsoft is trying to steer away from MS-DOS, these files are not required for Windows 95, Windows 98, Windows NT, Windows ME, Windows 2000, Windows XP, or later operating systems. However, in some cases it may still be necessary for users to edit or configure these files.

HOW TO EDIT THE FILES

The auotexec.bat and the config.sys are most commonly edited by the MS-DOS command file Edit. To edit these files, type edit c:\autoexec.bat to edit the autoexec.bat file, or edit c:\config.sys to edit the config.sys file. If the mouse drivers are not loaded properly you will not have the capability of navigating the

REMARKING INFORMATION

Remarking lines within the autoexec.bat or the config.sys allows you to temporarily or permanently prevent a line from loading each time you boot the computer. This is done by placing "REM " in front of the line you wish to skip.

If you are encountering issues with a line in the autoexec.bat it is highly recommended that you remark the line instead of removing it. This will prevent issues from arising if the line needs to be placed back into the autoexec.bat.

GETTING ADDITIONAL MEMORY

The below commands will help allow your computer to load programs into memory more efficiently allowing you to have more memory for MS-DOS programs / games.

Ensure you have the below three lines at the beginning of your config.sys file.

DEVICE=C:\WINDOWS\HIMEM.SYS DOS=HIGH,UMB DEVICE=C:\WINDOWS\EMM386.EXE NOEMS

By placing the DOS=HIGH,UMB on the second line, this can, in some cases, save memory because it is loading DOS into upper memory before loading the memory manager. Additionally, the first and third lines cannot be loaded into high memory because these lines are the memory managers.

INDEX

Category: Hardware Software Companies: None Related Pages: MS-DOS Windows 3.x Windows 95 Windows 98

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mouse.

If you have Windows 95, Windows 98, or later versions of Windows it is recommended that you use the sysedit command; to run this program, click Start / Run and type sysedit.

Load all your devices in your config.sys and autoexec.bat into high memory.

AUTOEXEC.BAT LAYOUT

Below is an example of what an autoexec may look like:

@echo off SET SOUND=C:\PROGRA~1\CREATIVE\CTSND SET BLASTER=A220 I5 D1 H5 P330 E620 T6 SET PATH=C:\WINDOWS;C:\ LH C:\WINDOWS\COMMAND\MSCDEX.EXE /D:123 LH C:\MOUSE\MOUSE.EXE DOSKEY CLS

COMMAND EXPLANATION

@echo off Tells DOS to just read the lines but don't echo them back to the screen.

SET SOUND=C:\PROGRA~1\CREATIVE\CTSND

This example is for the particular sound card that we have in one of the machines that we have. The set sound is telling the computer to send all sound events that the computer may run to that directory.

SET BLASTER=A220 I5 D1 H5 P330 E620 T6

Tells the computer to set the sound blaster settings. This is a good line for game players; if you have this line in your autoexec.bat you will know all settings for your sound card. A220 = port address "220", I5 = IRQ 5, D1 = DMA 1 usually being the settings you will need for any game out on the market.

SET PATH=C:\WINDOWS;C:\ Sets the computer to look in the C:\windows directory or the root if a command used at the prompt is not found.

LH C:\WINDOWS\COMMAND\MSCDEX.EXE /D:123

Line used for the CD-ROM. If you have Windows 95+, the MSCDEX will always be in the C:\WINDOWS\COMMAND. In Windows 3.x or DOS, this will usually be either in C:\DOS or C:\WINDOWS directory. The /D:123 is the name of the driver name that loads in upper memory; this can be anything, usually /D:MSCD0001. However, this is not an actual driver, this is just the name for the driver. Ensure if you change this line that you change it in the config.sys on your CD-ROM line. If the two are not the same, your

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CD-ROM drive will not load.

LH C:\MOUSE\MOUSE.EXE Loads the mouse driver into memory. However, not all mice use the same drivers. Although the mouse may use mouse.exe it could also be "mouse.com" or "mouse.sys", which is loaded in the config.sys.

C:\DOS\SMARTDRV.EXE /X Loads the smartdrive disk cache utility into memory. See our smartdrv command page for additional information about this utility.

DOSKEY Simple dos command to load DOSKEY into memory so when in DOS you can use it without having to load it.

CLS MS-DOS command to clear screen.

WIN Used for users using Windows 3.x, this line will load Windows automatically when booting the computer.

CONFIG.SYS LAYOUT

Below is an example of what the config.sys may look like:

DEVICE=C:\WINDOWS\HIMEM.SYS DOS=HIGH,UMB DEVICE=C:\WINDOWS\EMM386.EXE NOEMS FILES=30 STACKS=0,0 BUFFERS=20 DEVICEHIGH=C:\WINDOWS\COMMAND\ANSI.SYS DEVICEHIGH=C:\MTMCDAI.SYS /D:123

COMMAND EXPLANATION

DEVICE=C:\WINDOWS\HIMEM.SYS The Himem.sys line is a very important line; this line will allow you to load drivers into high memory. If this line is not present, Windows 3.x will not load.

DOS=HIGH,UMB This line will load DOS into high memory in an upper memory block. Note the location usually best placed after the HIMEM.SYS.

DEVICE=C:\WINDOWS\EMM386.EXE NOEMS The EMM386 line loads the extended memory manager, however note that some MS-DOS games have problems with extended memory and will not run without the NOEMS statement.

FILES=30 The files line allow Windows to load 30 files at the same time. Usually, however, going higher may decrease the computer's performance; 30 is found to work the best. Also ensure that this line is all as one line and that there is not a space between and after the =.

STACKS=0,0 The stacks line was first used in MS-DOS 3.2 and

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was used to swap the stack whenever an asynchronous hardware interrupt occurred. Later in MS-DOS 3.3 the line STACKS=0,0 was added into the config.sys. In special circumstances, this line was changed to STACKS=9,128.

The STACKS statement has a range of 8-64, 32-512. If a higher value is entered you will receive a FATAL : Internal Stack Failure, System Halted error message.

BUFFERS=20 Buffers line is to load buffers into memory allowing Windows to load memory.

DEVICEHIGH=C:\WINDOWS\COMMAND\ANSI.SYS The ansi.sys line is a driver for DOS to allow you to have different colors / sizes and special characters at the DOS prompt.

DEVICEHIGH=C:\MTMCDAI.SYS /D:123 This line is the name of the CD-ROM driver on the particular system we are working on. The /D:123 represents the name of the driver, which in this case is named 123, however, can be named anything, usually MSCD0001. Note, however, that /D:123 must be exactly the same in config.sys and autoexec.bat; if they are different, the CD-ROM will not work in DOS.

LASTDRIVE= Allows you to specify the last drive installed on the computer. It is not recommended this line be used unless you are using Windows 3.11 or below. This line can cause issues with Windows 95 & 98 and will generally be remarked by Windows automatically.

FCBS= Line used to specify the number of file-control blocks for file sharing. This line should only be used when programs require it, and today, is generally not used or required. FCBS can utilize between 1 and 255.

TECHNICAL SUPPORT

Reference Issue / Question

FORUM If your question is not listed on this page, please try our online forum.

CH000007 Getting the mouse to work in MS-DOS

CH000210 As the computer boots I receive bad command or file name.

CH000360 How to get sound in MS-DOS.

MS-DOS issues with Windows ME.

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CH000361

CH000382 Stack overflow system halted.

CH000425 Himem.sys missing or corrupt.

DEBUG ROUTINES Computer Debug Routines / Machine Code

DISCLAIMER

The below debug routines are listed to help test and view extended information on your computer. However, some of these debug routines can also potentially damage computer components or cause them not to work properly. We are providing these debug routines as a reference. If these cause problems with the computer they are run on, Computer Hope will not be held responsible for your actions. We recommend that only experienced computer users run these commands and that you are fully aware of the potential hazards of using these routines.

When running any of the below routines you are agreeing to the above statement.

DEBUG ABCs

Debug is a MS-DOS command which can be used to enter machine language into the computer either to create programs or test computer peripherals by receiving back various computer machine code.

Within this page as well as other pages you will begin to understand how to utilize this great method of

LISTING OF ROUTINES

TESTING PORTS CLEAR CMOS PRINTER TEST JOYSTICK TEST ERASE SECTOR 2 ERASE ALL HDD INFORMATION ERASE HDD AND CLEAR CMOS DISCHARGE OLD LAPTOP BATTERIES REBOOT YOUR COMPUTER CREATE A SLEEP FILE FOR DOS CHECK BIOS DATE VIDEO CARD TYPE

UNDERSTANDING RESPONSES

Several of the debug routines listed within this page as well as several other of our pages will return responses in Hexadecimal format. It is recommended if you wish to understand some of the code within these routines that you get a familiarity of Hexadecimal. You can find information about Hexadecimal as well as Binary on our Binary & Hexadecimal page.

POSSIBLE ISSUES

If during the time you are typing the debug routine you receive ^error this is and indication that you have incorrectly typed something within the line just

INDEX

Category: Hardware Companies: None Related Pages: Creating Batch Files Computer BIOS Help

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testing computer hardware, as well as learn the basics of machine code.

Additional information on the MS-DOS command debug can be found on our debug page.

completed. You can type the line again without causing any problems with the routine.

ENTERING DEBUG

Debug has been included in every version of MS-DOS as well as Windows. When running any of the debug routines it is recommended that if you have Windows that you exit or shut down to get into a real DOS prompt (unless you're running Windows ME, Windows 2000, Windows XP, or later versions). Additional information about getting into MS-DOS can be found on document CHDOS.

Once at the MS- DOS prompt, run through the below example, this example is perfectly fine to run on any PC Computer running MS-DOS / Windows and will not harm anything.

Type debug and press enter. This should get you to a - (small dash). This is the debug prompt. At the - type d40:00 and press enter; this will return several lines of information. (See Testing Ports for explanation of this feedback.) After the feedback you will be back to the debug prompt. To exit out of debug type q and press enter. This will return you back to the MS-DOS prompt.

In some of the below debug routines you will notice that a "g" is typed, then "q". G tells the computer that the code type is not self executing and must be run at this point. If completed, the program will return Program Terminated Normally which indicates you can now quit from the debug program.

TESTING PORTS

The below debug routine will check the ports of the computer to allow you to know if ports are being detected or not.

Type debug to get to the "-"

Type D40:0

You should get several lines; however, the first line is the only important line, which should read the following:

0040:0000 F8 03 F8 02 E8 03 E8 02 - 78 03 78 02 BC 03

F8 03 F8 02 E8 03 E8 02 78 03 78 02 BC 03

COM1 COM2 COM3 COM4 LPT1 LPT2 LPT3

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The above graph shows you what the feed back means as far as port, so if you see F8 03, this would be an indication that COM1 is being detected; if you see 00 00, this is an indication that it is not being detected, which could mean that hardware is bad or that it is disabled in CMOS.

Once you have finished looking at the information, type Q and press enter to get out of Debug.

CLEAR CMOS

The below debug routine will clear CMOS, BIOS, Passwords, Settings, Viruses, and other items residing in the CMOS. During this process you may get returned characters which are an indication that the string has gone in, if you by chance get ERROR ensure that you have typed the line in correctly, if not retype. Ensure that you do not skip any lines, that it is ALL typed in correctly to help prevent problems. Before running this Debug routine also ensure that you have read the above disclaimer.

After typing debug you will get "-" which is were you can begin by typing A and pressing enter.

A <ENTER> MOV AX,0 <ENTER> MOV AX,CX <ENTER> OUT 70,AL <ENTER> MOV AX,0 <ENTER> OUT 71,AL <ENTER> INC CX <ENTER> CMP CX,100 <ENTER> JB 103 <ENTER> INT 20 <ENTER> <ENTER> Note: Nothing is typed on this line G <ENTER> By pressing G this will execute the above script, ensure you have read and agree to the above disclaimer. Q <ENTER>

Then reboot and you will get a Setup Checksum Error. Go into setup, correct all the incorrect values, time, date...

JOYSTICK TEST

This test will test to see if your Joystick is present or not.

Type debug from the DOS prompt once at the "-".

Type i201

If you get a FF response attempt hold one of the main buttons on your joystick, and while holding the button down type i201 and see if a different response is given, each button on the joystick

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should return a different response. However, some special joysticks, such as the Microsoft Sidewinder, which has more than 4-5 buttons, may not return a response for all extra buttons because these buttons are generally controlled through software.

If a FF is still given on each of the buttons on the game paddle or joystick, it is a good possibility that either the Joystick and or the Joystick port is bad. If possible, attempt these steps with another known working joystick.

However, if you are receiving different responses when pressing and holding the keys on the joystick, the computer hardware is working properly.

Type q and press enter to quit out of debug.

Extra Note: Computer Hope has experienced issues where this debug routine may not work under Windows NT. If you are currently running Windows NT, refer to our page for Joystick installation procedures.

See Joystick Help page for additional help.

ERASING SECTOR 2

Before doing the below routine ensure that you have read our disclaimer and that you're sure that this is safe to do on your hard drive. Some computer hard drive manufacturers may void your warranty if this routine is ran or in some situations this can cause damage to the hard drive. This routine is useful in clearing DDO and unknown partitions. If this routine completes successfully it will erase everything in Sector 2.

In the below debug routine, only type what is in bold from line 3 to 9, you will get a response if typed in properly. If you get a response continue to type the bold text as shown below in the below example.

A:\>debug

-FCS:200 400 0<enter> -ACS:100<enter> -xxxx:0100 mov ax,302<enter> -xxxx:0103 mov bx,200<enter> -xxxx:0106 mov cx,2<enter> -xxxx:0109 mov dx, 80<enter> -xxxx:010a int 13<enter> -xxxx:010c int 20<enter> -xxxx:0110 <enter>(without typing anything) -g <enter> Program terminated normally.

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-q <enter>

ERASE ALL HDD INFORMATION

This debug routine is used to erase all partition information on the hard disk drive and is only recommend for experienced users or users who are unable to delete the partition information through fdisk.

In the below debug routine, only type what is in bold from line 3 to 8, you will get a response if typed in properly. If you get a response continue to type the bold text as shown below in the below example.

A:\>debug <enter>

-F 200 L1000 0 <enter> -A CS:100 <enter> xxxx:0100 MOV AX,301 <enter> xxxx:0103 MOV BX,200 <enter> xxxx:0106 MOV CX,1 <enter> xxxx:0109 MOV DX,80 <enter>

(80 for hd 0 or 81 for hd 1 )

xxxx:010C INT 13 <enter> xxxx:010E INT 20 <enter> xxxx:0110 <enter> -g <enter> Program terminated normally -q<enter>

Once this debug routine is complete, reboot computer and all partitions should be erased. Before anything can be installed back onto the computer you must run Fdisk and recreate the partition as well as format the hard disk drive.

Additional information about fdisk can be found on our fdisk page.

Additional information about format can be found on our format page.

ERASE HDD AND CLEAR CMOS

Before doing the below routine ensure that you read our disclaimer as well as are sure that this is safe to do on your hard drive. Some computer hard drive manufacturers may void your warranty or this may cause damage to the hard drive when doing the below example. This routine is useful in clearing DDO and removing possible viruses. If this routine completes successfully it will erase everything from your Hard drive as well as your reset your CMOS values.

In the below debug routine, only type what is in bold from line 3 to 17, you will get a response if

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typed in properly. If you get a response continue to type the bold text as shown below in the below example.

A:\>debug <enter> -fcs:200 400 0 <enter> -acs:100 <enter> -xxxx:0100 mov ax, 0 <enter> -xxxx:0103 mov ax, cx <enter> -xxxx:0105 out 70, al <enter> -xxxx:0107 mov ax, 0 <enter> -xxxx:010a out 71,al <enter> -xxxx:010c inc cx <enter> -xxxx:010d cmp cx,100 <enter> -xxxx:0111 jb 103 <enter> -xxxx:0113 mov ax,302 <enter> -xxxx:0116 mov bx,200 <enter> -xxxx:0119 mov cx,1 <enter> -xxxx:011c mov dx,80 <enter> -xxxx:011f int 13 <enter> -xxxx:012l int 20 <enter> -xxxx:0123 <enter> (without typing anything.) -g <enter> program terminated normally If you are doing this debug routine to clear out a possible virus turn off your computer and wait and turn back on. -q <enter> Once back at DOS, reboot your computer

When your computer comes back on from doing the above you will get an error message as booting up the computer, such as "Invalid Configuration". You must enter CMOS and set the time and date, save, and reboot again. Once rebooted, you will then need to run fdisk and recreate the partitions. Once created, you will then need to format the hard drive and proceed as normal.

DISCHARGE OLD LAPTOP BATTERIES

The below debug routine is used for older laptop batteries (i.e. batteries made from 1990-1992), we do not recommend using this routine on any newer laptop batteries or any NiMH batteries

N DPDISCHG.COM <Enter> A <Enter> MOV DX,01E8 <Enter> MOV AL,F9 <Enter> OUT DX,AL <Enter> INT 20 <Enter> <Enter> RCX <Enter> 10 <Enter> W <Enter>

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Q <Enter>

This will write dpdischg.com to the current directory. To run this utility type dpdischg.

REBOOT YOUR COMPUTER

Implement this debug routine to reboot your computer.

DEBUG

E 40:72 34 12 RCS FFFF RIP 0000 G

To create a batch file that reboots your computer without having to type the above command each time, use the below example.

GOTO BEGIN E 40:72 34 12 RCS FFFF RIP 0000 G :BEGIN DEBUG < REBOOT.BAT

CREATE A SLEEP FILE

This file allows your computer to sleep for a specified amount of time. This file is not dangerous in any way; if typed improperly, more than likely the file will just not work.

Type Debug

You should get a "-" begin typing the below information; after each line you may get a response, do not press enter and type the next line after the response.

N SLEEP.COM A 100 MOV SI,0082 MOV AX,[SI]

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XCHG AH,AL XOR AX,3030 MOV BL,AL MOV AL,0A MUL AH ADD AX,BX MOV SI,AX MOV AH,2C INT 21 MOV BL,DH MOV AX,SI AAM OR AX,3030 XCHG AH,AL MOV [0160],AX MOV AH,09 MOV DX,0160 INT 21 MOV AH,06 MOV DL,FF INT 21 JZ 014C OR AL,AL JNZ 013F MOV AH,08 INT 21 MOV AL,FF MOV DX,016C PUSH AX MOV AH,09 INT 21 POP AX MOV AH,4C INT 21 MOV AH,2C INT 21 CMP BL,DH JZ 012D MOV BL,DH DEC SI JNZ 011A SUB AL,AL MOV DX,016C JMP 0142 DB "XX SECONDS", D, 24 DB " ", D, A, 24

RCX 79 W

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Q

Tip: You may cut and paste the above test into a notepad document and save the file with a .scr extension. Once saved from DOS, type debug < name of scr which should create the file; should be created SLEEP.COM.

Note: This file is also available on our utility download page.

CHECK BIOS DATE

The below debug routine is to check the date of your BIOS. All BIOS dates on PC compatible computers is stored at memory address FFFF5h. To display the date of your BIOS do the following:

At the C:\> type debug

- d FFFF:5 L 8

After typing the above command you should receive a string similar to:

FFFF:0000 30 34 2F-33 30 2F 39 38 4/30/98

The 4/30/98 would be the date of your computer BIOS.

Additional information about the computer BIOS can be found on our BIOS page.

VIDEO CARD TYPE

The below debug routine will list the type of video card within your computer. This is an excellent way of determining the chipset on the card or the card within your computer without opening the computer.

At the C:\> type debug

-d c000:0040

After typing the above command you should receive several lines of text similar to:

C000:0040 00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00 ................

C000:0050 E9 63 7B 00 B4 10 49 27 - E9 FE 2B E9 F7 2B 50 4D .c{...I'..+..+PM

C000:0060 49 44 58 00 5B 00 00 00 - 00 A0 00 B0 00 B8 00 C0 IDX.[...........

C000:0070 00 5B 53 54 42 20 6E 56 - 49 44 49 41 20 54 4E 54 .[STB nVIDIA TNT

C000:0080 20 76 65 72 2E 20 31 2E - 31 30 20 0D 0A 00 1B 43 ver. 1.10 ....C

C000:0090 6F 70 79 72 69 67 68 74 - 28 43 29 31 39 39 38 20 opyright(C)1998

C000:00A0 53 54 42 20 53 79 73 74 - 65 6D 73 20 49 6E 63 0D STB Systems Inc.

C000:00B0 0A 00 22 6C 2C 0A 01 00 - C3 50 24 7F E8 60 36 58 .."1,....P$..'6X

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As you can pick out in the above dump, this gives you enough information to determine the make and the year made on the video card. On line 4 you can see the make of this video card, which in this case is a N VIDIA TNT which would be the Riva TNT chipset. The next line you notice the version of the card and finally the line thereafter is the copyright or the year manufactured, generally.

If you are unable to capture any information which sounds like the video card, you can also type

-d c000:0090

The above line will give you a dump similar to the above example; however, it may have additional information about the video card. Additional information about computer video cards can be found on our Video Card page.

Computer Hardware

Information about computer Video Cards

QUICK LINKS

Video Card ABCs Resolution information Refresh rate information DirectX Info Video specifications Video Card standards Video memory specifications Troubleshooting Video definitions

VIDEO CARD ABCs

Video cards (video boards / video display boards / graphics cards / graphics adapter) are physical hardware circuit boards that connect to the Motherboard. Video cards are also now being placed onto the computer motherboard to help bring the cost down on computers. When the video card is connected to a monitor, it serves as the visual link between you and your computer, allowing you to view and manage your computer's

REFRESH RATE INFORMATION

The monitor refresh rate is measured in Hz, which can also be called frame rate, horizontal scan rate, refresh rate, vertical frequency, or vertical scan rate. When setting a monitor's Hz, for example, 75 Hz, which is the Hz rate specified by VESA for any video resolution above or equal to 640x480, means that the computer is going to redraw the screen 75 times per second.

Refresh rates below 75 Hz can produce an often-imperceptible flicker that can cause eyestrain after long viewing. While some cards can support as high as 120 Hz, sometimes even higher, it is recommended you run 85-90 Hz; rates beyond 90 Hz add an unnecessary processing burden.

DIRECTX INFO

First released in 1996, DirectX is a

INDEX

Category: Hardware Companies: Click here Related Pages: DirectX Info Alliance Promotion ATI Boca Chips Cirrus Logic Diamond Hercules LCD Matrox Monitor Number Nine Oak Technologies Paradise S3 SIS Western Digital

DRIVERS

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software data.

Video Cards must specify its video standards, allowing end users to know what video cards may or may not be capable of doing. With new computers, you will most likely find SVGA standard video cards, allowing you to run the majority of software applications as well as run at high resolutions.

Generally, most video cards shipped today are included with video memory. Video memory is built onto the video board and/or motherboard, allowing the video card to run at higher resolutions and run at more efficient speeds.

Video cards are most commonly found in the PCI slots; however, with the release of the Pentium II came the AGP (Advanced Graphics Port) support. This new type of slot was released on August 26, 1996. This new technology allows the card to run at 66 MHz, 32-bit bus.

With the increasing popularity of advanced gaming came a new breed of video cards known as the 3D accelerators. When originally released, these cards only had support for 3D and not 2D and commonly required an additional 2D card to fully work. Today, 3D accelerators support both 3D and 2D, contains several MB of memory and processor on the video card.

RESOLUTION INFORMATION

The below information applies to a desktop CRT monitor's resolution. If you would like more information about LCD display resolutions, please see our LCD page.

The below image is an example of a

set of APIs (Application Program Interface) developed by Microsoft to allow all programs to write instructions for hardware without knowing exactly what hardware is within the computer. Games which include DirectX will have the capability of utilizing multimedia and graphics accelerator features more efficiently. See our DirectX page for complete information and help with DirectX.

VIDEO SPECIFICATIONS

The above picture illustrates a 15 Pin Video Port connector pin assignments as well as size dimension. Below is a chart explaining each function of a Video Port connector.

PIN FUNCTION 1 Red Video 2 Green Video 3 Blue Video 4 Monitor ID 2

5 TTL Ground (monitor self-test)

6 Red Analog Ground

7 Green Analog Ground

8 Blue Analog Ground

9 Key (Plugged Hole)

10 Sync Ground 11 Monitor ID 0 12 Monitor ID 1

Video Card Drivers

RESOLVED Were you able to locate the answer to your questions?

• Yes • No

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screen running at 640 x 480 which means 640 pixels are going horizontally by 480 pixels going vertically. When increasing the resolution, the image will become smaller due to the screen displaying more pixels per inch.

When setting the resolution higher you must have the needed Video Ram to support that resolution. If by chance you set your resolution higher than supported by your computer's hardware, you will need to follow the below steps to change the resolution depending upon operating system.

For help in setting the video resolution on your computer, please see our troubleshooting video card section.

13 Horizontal Sync 14 Vertical Sync 15 Monitor ID 3

VIDEO CARD STANDARDS

Below is a listing of the most commonly found video standards in new and old computers. Within this chart, under the specifications column, you will find the types of resolutions this standard is capable of running.

DISPLAY SPECIFICATIONS MANUFACTURER

MDA

Monochrome only , text-only standard, text display at 80 x 25 Max of 720 x 350 resolution however each individual pixel is not accessible, because text-only.

Developed by IBM

CGA Color Graphics Adapter

Max of 640 x 200 (Monochrome) in Graphics Mode. Max of 160 x 200 (16 colors) in Graphics Mode. Max of 80 x 25 resolution in Text Mode.

Developed by IBM

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EGA Enhanced Graphics Adapter

Max of 640 x 350 (16 colors, 60Hz) in Graphics Mode. Max of 80 x 25 resolution in Text Mode.

Developed by IBM in 1984

PGA Professional Graphics Adapter

Max of 640 x 400 Developed by IBM

VGA Video Graphics Adapter

Max of 640 x 480 (16 colors) in Graphics Mode. Max of 320 x 200 (256 colors) in Graphics Mode. Max of 720 x 400 resolution in Text Mode.

Developed by IBM in 1987

XGA Extended graphics array

Upgrade to the VGA video card. Max of 1,024 x 768 (256 colors) in Graphics mode.

Developed by IBM in 1990.

SVGA No real definition however commonly referred to as Super Video Graphics adapter.

Dependent upon the amount of Video memory see below chart for all available modes.

SXGA Super XGA

Max of 1400x1050 in Graphics Mode

UXGA Ultra XGA

Max of 1600x1200 in Graphics Mode

WSXGA Wide SXGA

Supports resolution of 1600 x 900 pixels or 1600 x 1024 pixels

WUXGA Wided UXGA

WXGA Wide XGA

Max of 1366x768 resolution.

VIDEO MEMORY SPECIFICATIONS

As the video resolution and color depth increases, so do the required available resources. The below chart illustrates all of the resolutions and color depths available for PC computers and the amount of memory each of them take.

RESOLUTION / COLOR 512K 1MB 2MB 4MB 6MB

640 x 480 @ 8-Bit 256 Colors X X X X X

640 x 480 @ 16-Bit (65,000 Colors) X X X X

640 x 480 @ 24-Bit (16.7 Million Colors) X X X X

800 x 600 @ 8-Bit 256 Colors X X X X X

800 x 600 @ 16-Bit (65,000 Colors) X X X X

800 x 600 @ 24-Bit (16.7 Million Colors) X X X

1024 x 768 @ 8-Bit 256 Colors X X X X

1024 x 768 @ 16-Bit (65,000 Colors) X X X

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1024 x 768 @ 24-Bit (16.7 Million Colors) X X

1152 x 1024 @ 8-Bit 256 Colors X X X

1152 x 1024 @ 16-Bit (65,000 Colors) X X X

1152 x 1024 @ 24-Bit (16.7 Million Colors) X X

1280 x 1024 @ 8-Bit 256 Colors X X X

1280 x 1024 @ 16-Bit (65,000 Colors) X X

1280 x 1024 @ 24-Bit (16.7 Million Colors) X X

1600 x 1200 @ 8-Bit 256 Colors X X X

1600 x 1200 @ 16-Bit (65,000 Colors) X X

1600 x 1200 @ 24-Bit (16.7 Million Colors) X

TECHNICAL SUPPORT

General Video Card Support

MS-DOS / Windows 3.x Video Card Support

Microsoft Windows 95, 98, ME, NT, 2000 Video Card Support

Monitor information and help

GENERAL VIDEO SUPPORT

Reference Issue / Question

CHADD Additional information with installing computer hardware.

Drivers Video card drivers and manufacturer listing.

FORUM If your question is not listed on this page please try our online forum.

CH000188 What is Video Palette Snooping?

CH000193 Issues with adding new video card to computer that has on-board video.

CH000194 My monitor shifts when changing the resolution.

CH000195 Is it possible to have two video cards in one computer?

CH000258 How do I determine what type of video card I have?

CH000307 Determining the PCI Version.

CH000308 Determining the AGP Version.

CH000315 Black borders on side of screen.

CH000407 2464 configuration error at boot.

CH000438 No Input Signal message.

CH000541 I downloaded a video but I can only hear it and not see it.

CH000558 How to change a monitor refresh rate.

CH000843 How can I have a multiple monitor display on my computer?

CH000894 How can I split one large display into two?

MS-DOS / WINDOWS 3.X VIDEO CARD SUPPORT

Reference Issue / Question

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CH000115 Changing and or viewing video settings within MS-DOS.

CH000189 How to set the resolution or change the resolution/adapter in Windows 3.x

MICROSOFT WINDOWS 95, 98, ME, NT, 2000 and XP VIDEO CARD SUPPORT

Reference Issue / Question

CH000035 Lost video after upgrading to Windows 98.

CH000121 Distorted video after increasing the resolution in Windows.

CH000145 Which version of Windows 95 supports AGP?

CH000170 After Windows NT 4.0 installation video only runs at 16 colors.

CH000173 Multiple display Windows 2000 troubleshooting steps.

CH000190 How to set the resolution in Microsoft Windows.

CH000191 Unable to increase the resolution in Windows.

CH000195 Is it possible to have two video cards in one computer?

CH000292 Where to get OpenGL drivers?

CH000378 Set Windows font to big to change back.

CH000557 Windows fonts are poor quality and not smooth.

CH000560 Flipped monitor display in Windows.

CH000567 Black and white picture with laptop connected to TV.