Preliminary Documentation for PARSETUP 

     PARSETUP is a Parallel Printer Port device driver for id
Software's DOOM (tm) which will allow two computers to play
across a LapLink or InterLnk parallel cable. This file is a quick
and dirty substitute for real documentation.

     Connect your computers together using a LapLink or InterLnk
cable (see CABLE.DOC for wiring diagram).

     Use PARSETUP just as you would use IPXSETUP or SERSETUP. In
addition to the standard DOOM command line switches, PARSETUP
understands the following:

-player1
    Forces console to be player 1 (Indigo) to override the
automatic player choice. Player 0's machine is the "master" and
sends the network start information at the start of the game. This
option can sometimes be helpful when systems of vastly different speeds
are linked together for DOOM, or if you just want to manually decide
which player will be Green and which will be Indigo.

-port
    Specify the base I/O port for the printer in C-style hex
notation. Common values are 0x378, 0x278, and 0x3bc.

-irq
    Specify the IRQ setting used by your printer port. Can be any
value in the range [2..7], although printer ports are usually 5 or 7.

     PARSETUP defaults to I/O port 0x378, IRQ 7 which corresponds
to LPT1: on most systems.

-debug
     Causes PARSETUP to perform some rudimentary testing on your
parallel link cable. See the troubleshooting section of this
document for morte details.


Troubleshooting
                                    
     Q: I connected my computers together with a cable, but all I
see is "wrote: PLAY0_0" scrolling endlessly up the screen. What's
wrong?

     A: There are a couple of problems which can cause this. You
might have the wrong kind of cable; the wiring of the cable used
for PARSETUP must have AT LEAST the connections listed in
CABLE.DOC. Extra wires probably won't hurt, but too few wires or
wires which connect the wrong pins will prevent PARSETUP from
communicating across that cable. Once you have verified that your
cable is wired correctly, you can test the cable using the
InterLnk program which comes with recent versions of MS-DOS. 

     Alternatively, you can invoke PARSETUP with the -debug
switch, which will cause PARSETUP to perform a short test
procedure before starting play. Make sure that BOTH computers
start PARSETUP with the -debug switch as well as the -port and -
irq settings appropriate for each machine. Once started, PARSETUP
will attempt to send a sequence of numbers across the link to
test all possible bit combinations which may occur during a game.
If the cable is working correctly, the numbers should scroll
rapidly up the screen and the test should successfully conclude
within a few seconds. If the computers hang on "Waiting for 0..."
it's possible that there is an incorrect -port setting on one of
the machines. Depending upon the type of printer port installed
in the machine, the base port address can be 0x378, 0x278, or
0x3bc. My suggestion is to try all three values and see if one of
them works. On the other hand, if the computers hang on a number
> 0, the port setting is correct but it's possible that one or
more of the connections needed by PARSETUP is open (i.e. not
connected). Double check your cable and try again.

     Q: OK, I did all of the above, and both computers pass the -
debug test sequence, but when I try to play I *still* get an
infinite list of "wrote: PLAY0_0" strings on my screen. What
gives?

     A: Since you verified that the port address and cable
connection are both OK in the earlier steps, the next problem
area involves interrupt request (IRQ) settings. A printer port
can be configured to generate an Interrupt ReQuest on one of the
available IRQ lines, usually IRQ7. In most systems, the interrupt
capability of the printer port is unused. For this reason,
systems are often configured such that network cards, sound
cards, mouse cards, or some other peripheral makes use of this
"unused" printer port IRQ line. This situation is bad news for
us, since two separate cards on a PC expansion bus cannot share
the same IRQ level. Thus, if your network card or your
SoundBlaster is set to use IRQ7, and your printer port card tries
to use IRQ7 also, the result is a conflict and PARSETUP probably
won't work.

     To correct this, make a note of the IRQ settings on each
card plugged into your PC's expansion bus, as well as the actual
IRQ setting used by your printer port. If you do find a conflict,
you must change one of the cards to use a different IRQ. NOTE:
Some motherboards with built-in printer ports allow you to
enable, disable, and change the printer port IRQ settings using
jumpers on the motherboard or in the BIOS SETUP. Check your
computer documentation for more information. 

     Once you have reconfigured your expansion cards to avoid IRQ
conflicts, retry PARSETUP.


TO REPORT BUGS:

To help me track down any bugs you might encounter, I'll need as
much information as possible relating to your system
configuration. In particular, the following info for BOTH
computers used in your game session would be helpful:

Processor (386, 486, Pentium, Intel/AMD)
Clock Speed (33Mhz, 66MHz, 90Mhz, etc.)
Printer port BIOS designation (LPT1:, LPT2: or LPT3:)
Printer port base I/O address you used on the PARSETUP command
line Printer port IRQ you used on the PARSETUP command line
Other command line switches passed to PARSETUP (e.g. -altdeath, -file)
Results of running PARSETUP with the -debug switch

Email questions, comments, and bug reports to asre@uiuc.edu