Users Guide

The following subsections discuss errors that can occur as a result of software operation or configuration.
Error Messages
Error messages can be produced by an application program, the operating system, or the computer. Messages and Codes
discusses the error messages that are generated by the computer. If you receive an error message that is not listed there,
check the operating system or application program documentation.
Input Errors
If a specific key or set of keys is pressed at the wrong time, a program may give you unexpected results. See the
documentation that came with the application program to make sure that the values or characters you are entering are
valid.
Make sure that the operating environment is set up to accommodate the programs you use. Keep in mind that whenever
you change the parameters of the computer's operating environment, you may affect the successful operation of the
programs. Sometimes, after modifying the operating environment, you may need to reinstall a program that no longer
runs properly.
Program Conflicts
Some programs may leave portions of their setup information behind, even though you have exited from them. As a
result, other programs cannot run. Rebooting the system can confirm whether or not these programs are the cause of the
problem.
There are also programs that use specialized subroutines called device drivers that can cause problems with the
computer system. For example, a variation in the way the data is sent to the monitor may require a special screen driver
program that expects a certain kind of video mode or monitor. In such cases, you may have to develop an alternative
method of running that particular program—by creating a start-up file made especially for that program, for example.
Call the support service for the software you are using to help you with this problem.
Avoiding Interrupt Assignment Conflicts
Problems can arise if two devices attempt to use the same interrupt request (IRQ) line. To avoid this type of conflict,
check the documentation for the IRQ line's default for each installed expansion card. Then consult Table 1, IRQ Line
Assignment Defaults, to configure the card for one of the available IRQ lines.
Table 1. IRQ Line Assignment Defaults
IRQ Line Used By/Available
IRQ0 Used by the system timer
IRQ1 Used by the keyboard to signal that the output buffer is full
IRQ2 Used by interrupt controller 1 to enable IRQ8 through IRQ15
IRQ3 Used by serial port 2 (COM2 and COM4)
IRQ4 Used by serial port 1 (COM1 and COM3)
IRQ5 Available unless used by a secondary parallel port
IRQ6 Used by the diskette drive controller