Zeus Tech Note
Trouble-Shooting and Debugging
(This document last revised May 8, 1997, version 0.5)
Copyright © 1996-1997. Zeus
Productions. All Rights Reserved.
Written by Bruce A. Epstein
The first step towards fixing a problem is to determine its exact nature.
To say "it doesn't work" is not very helpful. Try to narrow down
the problem by determining what does work, which will leave you with
a better understanding of where the problem lies.
Q. What are some common sources of error?
The most common error is a syntax error or
typographical error, such as an incorrect file name or file path. Verify
and physically retype the command or file path to make sure that
they are correct.
Q. What should I try?
The key is try different components to see
if they are the cause. If they are, you have solved the problem, if not
you have gained useful information and narrowed down the possible sources
of error.
- Consult the documentation, FAQs and examples provided
- Test on a system that is as "clean" as possible. Quit all
other applications. Temporarily disable other Xtras or XObjects. Reboot
to make sure that you have a fresh start.
- Test on another machine to determine if the problem is machine-specific.
- Test with a well-worn version of the operating system. Avoid older
versions, or brand new untested versions, or systems with beta software
installed.
- Test with a different application to determine if the problem is application-specific
- Make sure you have sufficient RAM to determine if the problem is memory-related.
- Make sure that you have the latest version of the application. Re-install
if necessary.
- Test it at a different color depth, such as 256 colors or thousands
of colors.
Windows Specifics:
- Test on both Windows 3.1 and Windows 95 to see if it is peculiar to
the Windows OS.
- Test it on several 486s and a Pentiums to determine if the problem
is particular to one machine or processor.
- Test a Windows 3.1 (16-bit) projector, and a Windows 95 (32-bit) projector
to determine if the problem is projector-specific.
- Test it on a system with a different video card.
Macintosh Specifics:
Q. How can I narrow down the problem?
The best approach depends on the nature of
the symptoms. If there is smoke coming out of your computer, re-installing
the software probably won't help. It is common to have no idea where the
problem lies, so you have to start somewhere based on what you know. Conceptually,
the trouble-shooting process is always the same, whether you are fixing
your car, your body, your computer or your love life.
- Define what is not working
- Decide what would constitute a satisfactory solution
- Delineate the major components of the system
- Discover which components are working or and which are not
- Debug the broken component
Q. How do I know where to start?
Start with the most likely causes that are
easiest to check, and eliminate possibilities as you progress.
Possible sources of error fall loosely into the following categories:
- Likely to be the problem and easy to check
- Unlikely to be the problem, but easy to check
- Likely to be the problem, but difficult to check
- Unlikely to be the problem, and difficult to check
One generally assumes that components that have previously worked are still
working. For example, if your printer has worked reliably for years and
suddenly stops printing, you might assume that the cable has come loose.
On the other hand, if the printer never worked, you might think it was damaged
in shipping, or that the wrong cable is being used.
If something works partially or intermittently, this often represents the
greatest challenge. Suppose a printer provides poor output. It could be
something obvious such as the laser printer is low on toner, or something
more subtle, such as the wrong type of paper being used.
The most difficult categories to solve are:
- Intermittent problems which are hard or impossible to reproduce
- Problems that are beyond your control, such as basic incompatibilities
between third party hardware or software
- Problems which don't conform to the basic assumptions we have made.
For example, if you follow the documentation, assuming it is correct, when
in fact the documentation is at fault. Another example might be a problem
caused by intermittent power surges, whereas the common assumption is that
your outlet works properly.
Q. How do I actually check the suspected culprit?
As with any undertaking, it helps if you have
the right tools and a modicum of patience and experience. Sometimes there
is no way to verify or fix a problem without the right tools. One tried
and true approach is to substitute a known working part for the suspected
culprit. For example, if your printer does not work with your cable, but
another cable works, then you know that your cable is at fault.
This can be extraploated to other areas. It is generally easy to swap printers,
monitors, cables and even computers. It is somewhat more difficult to swap
Q. Once I have determined the problem, how can I solve it?
After you have determined what is going wrong,
you can make a guess at its cause. An error may be easy to fix, such as
a simple syntax error. Consult the documentation for the proper syntax,
make the correction and try the application again.
Other possible solutions fall loosely into the following categories:
- Likely to work and easy to implement
- Unlikely to work, but easy to implement
- Likely to work, but difficult to implement
- Unikely to work, and difficult to implement
Q. Why can't I get it to work on all machines?
This is one of the great questions of all
time. If you can get your project to work on 90% of installed base of
PCs you are doing well. If on the other hand, your project is failing on
every PC, the problem is most likely with your Lingo code, an Xtra or your
Projector.
For example, most GPFs are caused by
conflicts with audio and video card drivers or a misconfigured system. Encourage
users to upgrade their drivers, and/or use the Generic VGA 640x480x256 video
driver that is available from Microsoft (it ships with Windows for Workgroups,
and can be downloaded from Microsoft too).
You should obtain the details of the user's configuration (i.e. make, processor,
video and sound cards/drivers, available RAM, etc.) and contact Macromedia
regarding known problems with the given hardware/software setup. They maintain
a KnowledgeBase which probably has known configuration specific conflicts
listed. They also provide a list of known good and bad video cards in a
text file that comes with Director called VIDSOUND.WRI.
Consult the Director for Windows README files regarding creating a custom
DIRECTOR.INI file that may help in certain situations.
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Copyright © 1996-1997. Zeus
Productions. All Rights Reserved.
(This page last revised May 9, 1997)