Patching DOS 3.3 To Use DRIVPARM:

Drivparm can be used with IBM 3.3 and other 3.3 DOS'S! The
following text explains why someone would want to use this and all
of the pains I went thru to get it to work:

First of all I will explain why someone would want to do this. The
only replacement for DRIVPARM is DRIVER.SYS which is external and
has to be loaded. When DRIVER.SYS takes hold it assigns a device
driver for whatever you are using for the next logical drive
available. Example: A well loaded AT class machine with Drive A:
being a 1.2 meg floppy, Drive B: is a 720k 3 & 1/2" drive, A hard
disk which is split into 2 logical drives C: & D:, and Expanded
memory of around a meg for a RAM disk (E:). DRIVER.SYS defined as
DEVICE=DRIVER.SYS /D:1 /F:2 would place drive B: as drive E: or F:
depending on the ram disk. ASSIGN.COM would take care of the drive
calls but DRIVER.SYS and ASSIGN.COM eat memory!

Thats why DRIVPARM is better. It sets up a device definition for
the drive you are installing and does it with less memory used
because it is a internal CONFIG.SYS command that is not loaded.
This patch I will descibe to you will make 1 change to the syntax
of DRIVPARM. Here is old verses new after the patch:

                  OLD:   DRIVPARM=/D:n /F:n etc...
                  NEW:   DRIVPARM=/DD:n /F:n etc...
                       (Note the extra 'D')

3.3 DOS was setup not to use DRIVPARM because most Computer Co's
were upgrading there BIOS's in AT class machines to set up new
devices in there CMOS Setup Memory. Anything that the SETUP
routine in CMOS could not handle DRIVER.SYS could be loaded and
used instead. After careful examination of the system files of IBM
3.3 DOS I found that DRIVPARM was still embedded in the code of
the IBMBIO.COM hidden file that DOS uses to boot. Stranger yet I
discovered that DOS did read a DRIVPARM=/ in a CONFIG.SYS file but
would not read further than the '/'. I found a way to hook it back
up to read the DRIVPARM command line without the CONFIG.SYS ERROR
being displayed at bootup.

Well Lets Patch 3.3 IBMBIO.COM:

First and MOST IMPORTANT make a work disk by formatting a floppy
with the /s command and also copy DEBUG.COM to it. Make sure your
prompt is A>. Use your favorite utility to change IBMBIO.COM's 
attributes so we can read-write to it. Type DEBUG IBMBIO.COM and 
press ENTER.

At the - prompt type R and press ENTER

A table will be displayed. Note what CX=nnnn and write this 4 Hex
digit down somewhere.

Now we look for the code to change. Type the following noting that
nnnn is CX= you wrote down:    S 100 L nnnn 3C 2F 74 03
Press ENTER and you should get a single line location for the
list. If you get more than 1 line of location double check what
you typed after S 100 L. You should see something similar as this:

                          ????:nnnn

The nnnn is what we looked for. So now type the following using nnnn:

                            U nnnn

You should get a assembler type listing of code starting at nnnn.
Now look where the hexidecimal code 74 falls near the top of this list.
We need to change this from 74 to EB. My IBM DOS 3.3 had this 74
located at 4E9C. Other 3.3 DOS's will be differ from this. Lets refer
to the location of 74 as xxxx.
Now to change it to EB type the following with xxxx being the location
of YOUR code 74:

                            E xxxx

It should display 74 and a space and wait for your input. Type EB and
press ENTER.
Now press W at the - prompt and it will save our patch to disk. Then
type Q to quit debug.

Okay, you have made it this far. Now make a CONFIG.SYS file with a text
editor of your choice or COPY CON CONFIG.SYS is just as fast. Use the
syntax of DRIVPARM=/DD:d /F:n. DO NOT FORGET the EXTRA 'D' in the line
you define. DRIVPARM follows the same syntax as DRIVER.SYS in your DOS
manual with the exception that DEVICE= is not required in front of it
and we now have to put 2 'D's in there with this patch.

Now save your CONFIG.SYS and try it out. Make sure your WORK DISK is in
drive A: and reset the computer. If there was a mistake made one of 2
things will happen. It wont boot period or you will get a ERROR IN
CONFIG.SYS FILE message. If no mistakes were made you should get a date
and time prompt. Then test it with the floppy for a while and make sure
that it works with your device defined in DRIVPARM. Then if it is okay
you can format your hard disk from this disk and run from there.

                                    From K. MACY