A Gathering Places, Conflict Troubleshooting

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Hardware Conflicts | Software Conflicts

Conflict Troubleshooting

Fortunately conflicts are almost always the result of a PC upgrade gone awry. Thus a technician can be alerted to the possibility of a system conflict by applying the last upgrade rule. The rule consists of three parts:

A piece of hardware and/or software has been added to the system very recently.
The trouble occurred after a piece of hardware and/or software was added to the system.
The system was working fine before the hardware and/or software was added.

If all three of these common sense factors are true, chances are very good that you are faced with a hardware or software conflict. Unlike most other types of PC problems that tend to be specific to the faulty subassembly, conflicts usually manifest themselves as much more general and perplexing problems. The following symptoms are typical of serious hardware or software conflicts.

The system locks up during initialization.

The system locks up on a particular application.

The system locks up randomly or without warning regardless of the application.

The device that was added might not function (even though it seems properly configured)

The system might not crash but a device or application that was working previously no longer seems to function.

The fastest way of overcoming conflict is to remove the hardware or software which resulted in the conflict. In other words if you installed board X and board Y ceases to function, board X is probably conflicting with the system. Removing board X should restore board Y to normal operation. The same holds true for software.

Unfortunately removing the offending element is no enough. You still have to install the new device or software in such a way that it will no longer cause conflict in the system.

Software Conflicts

There are two types of software that can cause conflicts in a typical PC: TSRs and device drivers. TSRs (sometimes called pop-up utilities) load into memory usually during initialization and wait until a system event (such as a modem ring or a keyboard hot-key combination.) There are no DOS or system rules that define how such utilities should be written. As a result, many tend to conflict with application programs (and even DOS itself).

If you suspect that such a pop-up utility is causing a conflict, find its reference in the AUTOEXEC.BAT file and disable it by placing the command REM in front of its command line (REM C:\UTILS\NEWMENU.EXE\A:360/D:3) The REM command turns the line into a REMark that can be easily removed later if you choose to restore the line. Remember to reboot the computer so that your changes will take effect.

Device drivers present another potential problem. Most hardware upgrades require the addition of one or more device drivers. Such drivers are called from the CONFIG.SYS file during system initialization, and use a series of command line parameters to specify the system resources that are being used. This is often necessary to ensure that a driver operates its associated hardware properly.

If the command line options used for the device driver do not match the hardware settings ( or overlap the settings of another driver) system problems can result. If you suspect that a device driver is causing the problem, find its reference in the CONFIG.SYS file and disable it by placing the REM command in front of its command line. (for example, REM DEVICE=C:\DRIVERS\NEWDRIVE.SYS /A360/I:5) The REM command turns the line into a REMark that can easily be removed later if you choose to restore the line.

Remember that disabling the driver in this fashion will prevent the associated hardware from working, but if the problem clears then you can work with the driver settings until the problem is resolved.

Remember to reboot the computer so that your changes will take effect. Finally consider the possibility that the software has a bug, try contacting the software manufacturer. There might be a fix or undocumented feature that you are unaware of. There might also be a patch or update that will solve the problem.

HARDWARE CONFLICTS

A PC user recently added a CD-ROM and adapter board to their system. The installation went flawlessly using the defaults-a 10-minute job. Several days later when attempting to back up the system, the user noticed that the parallel port tape backup did not respond (although the printer that had been connect to the parallel port had been working fine) The user tried booting the system from a clean bootable floppy disk (no CONFIG.SYS or AUTOEXEC.BAT files to eliminate the device drivers), But the problem remained. After a bit of consideration the user powered down the system, removed the CD-ROM adapter board, and booted the system from a clean bootable floppy disk. Sure enough, the parallel port tape backup started working again. Because the CD-ROM was the last device installed, it was the first to be removed. Now reinstalling the device without conflict will be the real challenge.

Ideally the way to correct a conflict would be to alter the conflicting setting That's good in theory, but another thing in practice. The trick is you need to know what resources are in use and which ones are free. Unfortunately there are only 2 ways find out. On one hand you can track down every user manual for every board in the system, then inspect each board individually to find their settings then work accordingly. This will work but it's very time consuming.

As an alternative you can use a resource testing tool such as the Discovery card by Allmicro Inc. Which plugs into a 16 bit ISA slot and uses a series of LED's to display each IRQ and DMA channel in use, then it is a simple matter of setting your expansion hardware to an IRQ and DMA channel that is not in use.

Remember that you might have to alter the command line switches of any device drivers.

Once you have determined the IRQ, DMA and I/O settings that are in use, you should note the settings on a piece of paper and tape it inside the case for future reference.

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