Contents of the WHTPRT40.DOC file
For detecting installed serial ports,
type of mouse, IRQs used by ports and mouse,
and potential IRQ conflicts
Copyright 1989-1991 Life Sciences Software
8925 271st St., N.W., Suite 112
Stanwood, Washington 98292
AUTHOR: Pete Petrakis (CIS 76555,1175)
IMPROVEMENTS IN THIS VERSION:
Version 4.0 of WhatPort is a substantial improvement over all previous
versions. For the first time the program is able to detect the IRQ
line actually being used by the serial ports, instead of assuming that
the standard IRQs are being used. This greatly increases the program's
usefulness in situations where unconventional IRQs have been assigned
to serial ports. The new version also detects and reports the base
address of each installed serial port.
This program detects what serial ports (COM1-COM4) are installed
in a standard (PC, XT, AT) or PS/2 system. The type of mouse, if
present, is also shown (serial, bus, InPort, PS/2, HP) together with
the interrupt request (IRQ) line it's using (unless it's a PS/2).
The program warns of potential IRQ line conflicts between the
mouse and serial ports. In the case of PS/2 computers, where
there should be no possibility of conflict between a PS/2 mouse
and a serial port, WHATPORT only reports the presence of the
PS/2 mouse and the characteristics of the serial ports it finds
installed (up to COM4).
Because standard PCs have only two IRQ lines for serial ports,
COM3 must share COM1's IRQ line and COM4 must share COM2's
IRQ line. Unfortunately, two devices using the same IRQ
line can't be active at the same time. COM3 can't be used for
a printer or modem if a serial mouse is active on COM1, for
example. Likewise, COM4 can't be used if a serial mouse is
active on COM2. In other words, if you have four COM
ports and a mouse is attached to one of them, you do not
have three COM ports available for other devices, you only
have two. The COM port that shares the IRQ line being
used by the mouse is not usable. WHATPORT detects and
reports such conflicts.
The following table shows what ports are available for other
devices in a conventionally configured PC, XT, or AT when a
serial port mouse is present on a multiple-port system:
Serial port mouse on Ports available for other devices
COM1 or COM3 (IRQ4) COM2 or COM4 (IRQ3)
COM2 or COM4 (IRQ3) COM1 or COM3 (IRQ4)
Conflicts with serial ports are also possible in the case of a
bus mouse. For example, if a bus mouse is configured to use
IRQ3, there will be a conflict with both COM2 and COM4. If it
is configured to use IRQ4, there will be a conflict with both
COM1 and COM3. WHATPORT also detects and reports these conditions
so a different IRQ can be selected for the bus mouse.
The PS/2 has a different arrangement. COM1 in a PS/2 uses IRQ4,
and COM2, COM3, and COM4 share IRQ3. There should not be any IRQ
conflicts with a PS/2 mouse in a PS/2 system since the PS/2 mouse
has its own port and does not use either IRQ3 or IRQ4. However, it
seems theoretically possible that someone could attach an ordinary
(non-PS/2) serial or bus mouse to a PS/2 machine, in which case
there could be IRQ conflicts. With that kind of setup, a bus mouse
using IRQ3 could make three serial ports (COM2, COM3, and COM4)
unusable on a standard PS/2.
As noted above, Version 4.0 does not assume that serial ports 1 to
4 are using the standard IRQ lines for a conventional or PS/2 computer.
Instead, it performs tests to determine which IRQ line each installed
serial port is actually using. Furthermore, it determines the base
address for each installed serial port. Thus Version 4.0 should
be useful with virtually any system configuration.
HOW TO USE THE PROGRAM:
Just run it and read the results. Adjustment for color or
monochrome display is automatic, but monochrome can be forced
by putting M on the command line.
Some special considerations apply in the case of PS/2 systems,
because the port addresses they use for COM3 and COM4 are different
from those in PCs, XTs, and ATs. Version 4.0 of WHATPORT will
automatically detect the presence of an IBM PS/2 system and check
the right port addresses. The option to declare the presence of a
PS/2 system with a command line switch has been eliminated from version
4.00 since experience shows that automatic detection of the system type
IRQ conflicts between the mouse and a port are reported with the message,
"POTENTIAL IRQ CONFLICT -- COMx and the mouse share IRQy"
where x is the number of the serial port and y is the number of the
IRQ line. The message will be printed for each installed serial port
that is using the same IRQ line as the mouse. If you see this message,
it means the specified serial port is probably useless for communications
or any other purpose. With a bus mouse, the conflict can be resolved
by assigning a different IRQ line either to the serial port (in a few
systems) or, most commonly, to the mouse. Options with a serial port
mouse are more limited. For example, a serial port mouse on COM1 will
not only tie up that port, it will also tie up COM3 unless there is
some way to give COM3 a different IRQ. (Note: The user assumes any
risk involved in IRQ assignments. It is advisable to consult the
mouse or serial port installation manual for guidance in picking the
WhatPort is widely used by computer consultants and others involved in
equipment installation and development, which is most gratifying to any
program author. Since the effort to continuously improve the program
is not without expense, it has become necessary to make the program
shareware and ask people to register and pay if they use it regularly.
Obviously, many people will use it only once, when they install a new
mouse, for example, and it seems pointless to expect them to register.
However, it does seem appropriate to ask those who use it regularly for
business, professional, or institutional purposes to support its
continued development. Beginning with Version 4.00, WhatPort is a
shareware program. The registration fee is modest, only $15 U.S.,
and your support will be very much appreciated. Please mail your
registration payment to the above address.
DISTRIBUTION AND DISCLAIMER:
WHATPORT.COM and this document are provided by Life Sciences Software,
Stanwood, Washington. They may be copied and distributed promiscuously
provided they are not sold, modified, or separated. Companies involved
in the distribution of diskettes containing shareware or free programs
are permitted to distribute these files and charge their normal fees for
that service. Although WhatPort has been extensively tested, Life
Science Software and Pete Petrakis make no warranty concerning its
usefulness in all systems and accept no responsibility or liability for
any harm resulting directly or indirectly from its use.
Life Sciences Software