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Appendix A Troubleshooting

Common Error Conditions

Problems and Solutions

Error Messages


This appendix describes problems you may experience with the operating system and suggests possible solutions. It is divided into three parts: the first part describes general conditions that commonly cause problems; the second part describes problems specific to certain areas, such as memory and the Task Manager; the third part explains fatal error messages.

NOTE: For a complete explanation of any error message that you see when using the operating system, consult DOSBook; from within DOSBook, type the following:

TROUBLESHOOTING <Enter>

Common Error Conditions

This section represents a ``checklist'' of some common conditions which can cause errors when you are using the operating system.

When absolutely nothing happens, remember to wait before assuming there is a problem; some programs take time to execute and some errors, such as disk I/O errors, cause the operating system to retry an operation many times before reporting an error. Once you are experienced with the operating system, you will know when a command is taking too long to complete.

No DOS partition prepared on your hard disk
You cannot access your hard disk until you prepare a DOS partition. Refer to the ``Command Reference'' chapter of DOSBook for a detailed description of FDISK, the disk partitioning utility.

Hard disk unit not switched on
An external hard disk unit may have its own electrical connection.

Peripheral devices not connected properly
Check that peripheral devices are properly connected to your computer and to electrical outlets.

File is read-only
If a file is set to read-only, you cannot edit the file. Refer to the ``Command Reference'' chapter of DOSBook for information about using the ATTRIB command to set the file to read-write.

Operating system cannot find file
By default, the operating system looks for a file in the current directory of the current drive and in any directories specified in your current PATH. You must specify the appropriate directory if the file is located elsewhere.

File is password-protected
You must provide the correct password in order to access a file if the file is password-protected. Refer to Chapter 14, ``Securing Information,'' for information about using passwords and security.

Incorrect version of the operating system being used
Many system commands will only run under the version of the operating system with which they are shipped. Refer to the description of the SETVER command in the ``Command Reference'' chapter of DOSBook for more information.

Diskette used incorrectly or damaged
The way in which you use diskettes is the source of many errors. Remember the following points:

File is corrupted
Files can be corrupted for many reasons but power failure is probably the most common cause.

If files are corrupted after you run a program that you wrote yourself, debug the program carefully; the program may be overwriting files or corrupting a directory.

To replace a damaged file, use your backup copy. If you do not have a backup copy, you may have to recreate the file.

Problems and Solutions

This section describes specific problems you could encounter with various operating system features and solutions to these problems.

Problems with Memory

Insufficient conventional memory

Explanation You are running out of conventional memory.

Action First, ensure that you are optimizing memory usage on your system; refer to Chapter 10, ``Managing Memory'' for detailed information.

If you think you have made all the necessary changes but still run out of memory, try the following:

Computer will not boot

Explanation Conflicting use of upper memory. Most likely, the memory manager is moving something into an area of upper memory also required by a hardware device driver.

Action Determine the cause of the problem by performing a ``clean boot'' and then editing CONFIG.SYS and AUTOEXEC.BAT to turn off lines one at a time (using REM or ?). Reboot after disabling lines that you suspect may be causing the problem to see if the problem remains. Refer to Chapter 9, ``Configuring the System,'' for information about performing clean boots.

If you determine that the memory manager is causing the problem by occupying an area of upper memory required by something else, use the /EXCLUDE option with your memory manager (EMM386.EXE or HIMEM.SYS) to exclude the area of memory causing the problem. Refer to the descriptions of EMM386.EXE and HIMEM.SYS in Chapter 10, ``Managing Memory'' for more information.

Packed file is corrupt

Explanation An application written with packing utilities is running in lower memory (the first 64 KB of conventional memory) because the memory manager has relocated the operating system. Lower memory is normally occupied by the operating system and the application you are running does not expect lower memory to be available.

Action Disable lower memory before you run the application (MEMMAX
-L). Re-enable lower memory after exiting the application (MEMMAX +L).

Program reports no EMS available

Explanation The program you are using requires EMS (expanded) memory but determines that none is available. The program may be assuming that the LIM page frame starts at a specific address.

Action Make sure that the LIM page frame address is defined the same way by EMM386.EXE (or EMMXMA.SYS) as it is in SETUP or in the documentation for the program. Remember that the /FRAME option defines the address of the page frame. Use the advanced memory management options in SETUP.

Program does not load into upper memory

Explanation One of the following:

Action Check that upper memory is available by running the MEM command. Upper memory blocks that are available will be marked as FREE in the ``Type'' column of the MEM listing.

If MEM indicates that upper memory is not being used, check that the memory manager you are using (EMM386.EXE or HIMEM.SYS) is correctly loaded in CONFIG.SYS. Pay particular attention to the
/FRAME, /INCLUDE, and /EXCLUDE options to make sure that any addresses in upper memory are correctly specified. A common error, for example, is to specify a letter O rather than the digit 0. Also make sure that if you do not require expanded memory, the /FRAME option is set to NONE.

Check that upper memory is enabled. HILOAD or LOADHIGH automatically enables and disables upper memory when you use it in AUTOEXEC.BAT to load a program high. You can still use MEMMAX +|- U at the system prompt to enable and disable upper memory.

Finally, if sufficient upper memory is shown as available but a HILOAD/LOADHIGH, HIINSTALL/INSTALLHIGH, or HIDEVICE/DEVICEHIGH command is still failing to put a program in upper memory, refer to the information about expanding files in Chapter 10, ``Managing Memory. The program you are trying to load could be expanding when it initializes and using more RAM than it will ultimately need. Therefore, there is not enough memory for the program to initialize itself in upper memory.

Problems with the Task Manager

Task terminates abnormally (task switching only)

Explanation The swap file may have increased in size.

Action Exit the Task Manager and delete the swap file to create more disk space. A new swap file with the same name will be created automatically.

Task reports insufficient EMS

Explanation The task you are running in expanded memory is not finding sufficient memory in which to run. Possibly, you have too many tasks currently loaded.

Action Remove some tasks from the Task Manager or change the maximum amount of EMS allowed per task and start the original task again.

Error Messages

There is a full list of error messages in DOSBook. This section explains error messages that may be generated in situations in which you are unable to access DOSBook, for example if the operating system crashes or fails to boot correctly.

Abort, Retry, Ignore, Fail ?

Source Several commands

Explanation Typically this message follows an error in a read or write operation.

Action You can respond by typing A, R, I or F.

If the reason for the error is obvious (such as no diskette in the target drive) then correct the error and type R to try again. A (for abort) stops the current operation. I (for ignore) results in the next stage of the current operation continuing, as if the error had not been detected. F (for fail) lets the current operation know that there is an error, and it may therefore continue or stop. In both the last two cases (ignore and fail) there is a risk of data being corrupted.

Bad or missing file

Source DOS startup procedure

Explanation The operating system either cannot find or cannot read the CONFIG.SYS file on the root directory of your startup disk.

Action Alter the CONFIG.SYS file and then restart the operating system. See the description of CONFIG.SYS in Chapter 9, ``Configuring the System,'' for information.

Can't load DOS file

Source DOS startup procedure

Explanation The IBMDOS.COM file may be missing or corrupt.

Action Start the operating system from your startup diskette. You will then need to copy the system files from that startup diskette back to the hard disk or diskette that failed. You can do this with the SYS command. Type SYS /? or SYS /H at the system prompt to see online information about SYS.

Command or filename not recognized

Source Any command

Explanation You have typed an invalid command.

Action Check the spelling (Chapter 8, ``Commands'' explains how to recall, edit, and reissue commands) and re-enter the command. Also check the path to ensure that the required program, if spelled correctly, should be found.

Data error

Source Any application

Explanation There is an error accessing the device specified.

Action Check the device (for example make sure it is connected properly). If the device being accessed is a disk drive (hard or diskette), this error implies that data on the disk is corrupt. Make backups of all non-corrupt files on the disk, and then either reformat the disk, or use a different disk.

Disk full

Source Any command

Action Erase some unwanted files from your disk and try again.

Drive not ready

Source Any command

Explanation The diskette is not correctly in the drive, or the drive door is still open.

Error reading system area

Source FDISK

Explanation This message implies a hardware failure.

Action Contact your dealer.

Failed to get current path on drive...(OS error code ...)

Source Several commands

Explanation This is probably an error on the disk in the drive mentioned or a problem with the disk drive itself.

Action Consult your dealer.

File not found

Source Several commands

Explanation The command cannot find the file specified in your command line.

Action Check the spelling of the filespec. If the filespec was spelled correctly, use DIR or XDIR to check the contents of other directories for the location of the specified file.

I/O error ...

Source Any application

Explanation An Input/Output error occurred while accessing the requested device. In the case of a diskette drive, this may mean a corrupt diskette.

IBMBIO.COM read error

Source Diskette system loader

Explanation The programs used to startup the operating system from diskette are corrupt or in the wrong order.

Action Start DOS from a different startup diskette. If you want to use the failed startup diskette again you will need to reformat it using the
/S (copy system files) switch within FORMAT.

Illegal drive in Path Specification

Source Several commands

Explanation You specified a drive that is not assigned in your system, or you mistyped the drive specification.

Action Retype the command with a valid drive.

Incorrect version of operating system

Source Several commands

Explanation The version numbers are different between the operating system running on your computer and the file containing the utility that you have just tried to load.

Action The best solution is not to keep any old version of the operating system on your disks.

Insert a boot diskette in A: then PRESS Ctrl/Alt/Del...

Source DOS hard disk system loader

Explanation This message follows any error message that arises from the hard disk system loader. The effect is to get you to restart the operating system from your startup diskette. No system files can be found.

Action Use the SYS command or re-install the operating system, as there are no files on the disk.

Internal error: System tables too large

Source Task Manager

Explanation The configuration on your computer is too complex, there is not enough memory to describe it and it has exceeded the internal structures created by the Task Manager.

Action Consult your dealer with details of your configuration, explaining the error message you received.

Invalid partition table

Source DOS hard disk system loader

Explanation More than one partition is marked as bootable (that is, able to start DOS), a non-existent partition is marked as bootable, or there is a hard disk failure.

Action Restart the operating system from diskette. Appendix B, ``Preparing the Hard Disk'' describes how to use FDISK to set the bootable partition. Note that FDISK formats the disk, and you will lose any data on the disk.

No operating system

Source Hard disk system loader

Explanation This message originates in software that your supplier provides with the hard disk.

Action Start the operating system from the diskette. Copy DOS onto the hard disk and then use FDISK to make the system partition ``bootable'' (that is, capable of loading DOS when the computer is started).

Not enough memory
Not enough memory for ...
Not enough memory to ...

Source Several commands

Explanation There is insufficient free memory for the command to work.

Action Free some memory by creating a smaller memory disk, or by removing memory-resident programs, or device drivers that you do not need. Then try the command again.

Not ready error

Source Any application

Explanation The device you are trying to access is not responding. In the case of a diskette-drive, this usually means there is no diskette in the drive, or the drive door is not shut. With hard disks, this error may mean a hardware failure.

Action Check that your diskette is inserted correctly into the diskette drive, and the door is shut. For hard disks, contact your dealer.

Operating system error

Source Several commands

Action If you get this error message, make a note of the situation in which it occurred, and contact your dealer.

Operating system load error

Source DOS hard disk system loader

Explanation The computer cannot read the operating system's loader file.

Action Restart the operating system from diskette. Backup your hard disk. Use FDISK to delete and then recreate the partition. Then recover your files from your backup.

Physical Media Error

Source Several commands

Explanation The operating system was unable to read from or write to a disk. The disk has probably been corrupted.

Action Copy as many files as you can from the corrupt disk to another disk and then reformat or dispose of the first disk.

Sector not found

Source Any application

Explanation The requested sector on the disk is not present, or is corrupt. With diskette-drives, this usually means that the diskette in the drive has not been formatted.

Seek error

Source Any application

Explanation The disk drive being accessed was physically unable to move its read/write heads to the requested location. This generally means a disk controller hardware failure.

Action Contact your dealer.

Unknown error code

Source Several commands

Action If you get this error message, make a note of the situation in which it occurred, and contact your dealer.

Use another boot disk

Source Diskette system loader

Explanation The programs used to startup the operating system from diskette are corrupt, or in the wrong order.

Action Startup DOS from a different startup diskette. If you want to use the failed startup diskette again you will need to run the SYS command. Enter SYS /? or SYS /H at the system prompt to see online information about SYS.


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