Game Killer/Game_Killer.bin/448.M29COMM.ZIP/M29COMM.TXT

Text File | 1993-09-01 | 9KB | 183 lines

                       M29COMM for MiG-29 version 1.00

                        By: Ken "Stinger" Richardson
                            UID: [70761,301]

The M29COMM.COM file is a TSR that will install itself in your computers
memory waiting for you to run MiG-29. Once you execute MiG-29, the TSR
becomes active replacing some of MiG-29's communications code. Using this
patch you will see your connection times improve greatly. During testing,
this patch completed a 2400bps direct connection in just over 2 minutes, a
57600bps V.42bis connection in just under 30 seconds. The improvement is
depended upon your computers CPU speed and hard drive speed. Slower computers
with slower hard drives will not link as fast as quicker computers. Another
problem slower computers might suffer would be UART Overrun errors. M29COMM
will recover from the occasional Overrun error but if you experience problems
connecting at high speed, try a lower baud rate.

        If you have your modem connected to COM3 or COM4, you can tell
M29COMM to force MiG-29 to use either of these ports by placing a /3 or /4
after typing M29COMM. If you do use the "re-map" feature, when you enter
MiG-29's COMMs screen COM1 will be COM3 or COM2 will be COM4. For example:

        M29COMM /3            ; This causes MiG-29 use COM3 when you tell
                                it to use COM1 from the COMMS screen.

        After you finish playing MiG-29, you can remove the M29COMM TSR from
memory simply by running it a second time.


V.42bis modems:

V.42bis is a CCITT standard for data compression and error
correction. It can give a modem up to 4:1 compression with 100%
reliability. A 9600bps V.42bis modem can achieve throughput of up
to 38,400bps and a 14.4kbps V.42bis modem can go up to 57,600bps
throughput. This is done by the modem by compressing the data it
receives from the computer before it sends it across the phone
line on it's 9600 or 14.4k bps carrier. The receiving modem
decompresses the data before sending it to it's host computer.
All data can not be compressed the same amount. For example, text
files can be compressed a great amout while ZIP file can't
because they are already compressed. Therefore the effective
speed of a V.42bis modem can vary from it's carrier speed (9600
or 14.4k bps) all the way up to 4 times it's carrier speed (38.4
or 57.6k bps). The way the data flow is regulated by the modem is
with FLOW CONTROL, or more specific harware flow control
(CTS/RTS). The CTS (clear to send) line will tell the computer
when the modem is ready for data. Your comm port might be set to
57,600bps while the modem is sending data at 15,000cps, obviously
the computer must wait for the modem. So as you can see, flow
control is absolutely needed when a V.42bis connection is made
between two computers with the comm ports set to a bps rate
higher than the modem's carrier.


Important Things to Know:

1. M29COMM does perform error checking and will recover if an error occurs.

2. M29COMM will support modem data compression (V.42bis and MNP-5). You must
have hardware flow control turned on (RTS/CTS). Check you modem's manual for
the proper commands although AT&F with generally work for most modems.

3. You will NOT see any satellite downlink "progress" indicators (the spinning
wheel and dots). This was skipped so I could gain as much speed as possible
by dedicating the CPU to the serial port.

4. When using M29COMM you will NOT be able to connect with someone who is not
using M29COMM. Both computers must run the TSR.


What to Expect from M29COMM:

1. You will see less "jittering" in your opponents plane.
2. There will be a 30% increase in cps rate while playing.
3. The Satellite Downlink will be considerably faster if your
   UART can handle a high speed connection. (See UART
   consideration)


UART (Universal Asycronosis Receiver/Trasmitter) Consideration:

A UART is the "brains" of your COMM port. It receives and sends
data to and from the modem, monitors line errors, and monitors
modem status. It will interrupt the CPU whenever data is ready so
the CPU can read every incoming byte without disrupting program
execution. What I have found while testing the original V42PATCH, is some
UARTs are not fast enough to achieve a reliable connection at
speeds over 9600 baud. For speeds over 9600 baud you may find
that you will need either a 16450 or probally a 16550 UART. These
chips are direct replacements for the old 8250 UART and are much
faster. If you have an internal modem, you can be sure that your
UART is fast enough as it is built into the modem. External
modems might have a problem. The UART is not contained in your
modem, it is part of your computer, so you may have a 14.4k bps
modem and have a weak link betweeen the modem and computer caused
by the slow UART.

If you are unsure if your UART can handle a high-speed
connection, try connecting with your opponent via a communication
program using same modem defaults that you intend to use in
MiG-29. Configure your comm port to the same baud rate you will
use in MiG-29 (38,400 or 57,600). Then try uploading/downloading
files to/from each other. If you experience errors, either your
UART or your opponent's is to slow. Most comm programs have an
option in their setup to enable CTS/RTS (hardware) flow control,
this must be on.


Tips on Connecting with MiG-29 using V42PATCH.EXE:

When connecting with a patched version of MiG-29, you will want
to have V.42bis turned on, also you need hardware flow control
enabled. Use your comm program to configure your modem for the
correct setup and then save your modems configuration in "Stored
Profile 0" in your modem's non-volitile memory. I found it is
also a good idea to make sure the "Extended V.42 Response Codes"
are turned off. After the proper configuration is stored in your
modem's memory, your are ready to connect. Go to the comms screen
and select 57,600bps and modem connection. Select call or answer,
whichever you and your opponent decided on. Use modem defaults
when MiG-29 asks, this is important. If you use defaults, MiG-29
will use "Stored Profile 0" to make a connection as a result of
the ATZ command MiG-29 will send. This is the configuration you
just saved. You should get a connect message and everything else
should work fine. Here is an example of how to setup your modem:

From TERMINAL mode in your comm program type:
AT &F                ;Return to factory configuration
AT &Q5               ;Enable V.42bis connection
AT &K3               ;Enable hardware flow control (CTS/RTS)
AT W0                ;Disable extended V.42 response codes
AT &W0               ;Store in Profile 0, very important.
AT &V                ;Display profile. Use this command to double
                      check your setup.

Note:  Your modem may have different commands than I have listed
here, check your modem's manual before you type these commands,
especially &Q5 and W0. Some modems use &M5 instead of &Q5. You
may even have to change some S-registers. Whateven you must do,
make sure the last thing you type is AT &W0 to store it in your
modem's memory. If you type an illegal command, your modem should
respond with ERROR, otherwise it will respond with OK.

I should mention that all 9600 V.42bis modems will not go to
57,600bps, some have a limit of 38,400bps which is fine. Using a
9600bps carrier and V.42bis compression (4 to 1), the maximum
throughput will be 9600 * 4 = 38,400bps. So 57,600bps has no
advantage when using a 9600bps modem/carrier. When using a
14,400bps V.42bis modem, you should select 57,600bps as all
14.4kbps modems will accept 57,600bps connections. If you have a
14.4kbps modem and your opponent has a 9600bps modem, you will
have to connect using a 9600bps carrier. The modems should do
this automatically. You can select 57,600bps (although it offers
no advantage over 38,400bps over a 9600bps carrier) when in
MiG-29 and your 9600bps opponent can select 38,400bps and you
will still have a good connection. Remember, with V.42bis turned
on, your computer is connected to your modem, not directly to
your opponent's computer. When you select the baud rate in
MiG-29, what you are doing is telling MiG-29 how fast you can
talk to your modem. The "Flow Control" with regulate the actual
data transfer rate between computers. I suggest selecting 38,400
baud when using a 9600bps carrier and 57,600 baud with a 14.4kbps
carrier.


Future Versions of M29COMM:

I intend to continually support M29COMM, upgrading it as future
versions of MiG-29 are released. I may also add more features as
the need arises.


Note:
This patch is not supported by Spectrum Holobyte. If you
experience problems, contact me in the ModemGames Forum.

Ken "Stinger" Richardson
[70761,301]

P.S. Have fun!!!