Quarterdeck Technical Note
by Dan Travison 10-30-89
Creating FIXINT1.COM using DEBUG
We have found compatability problems between QEMM versions 4.23 and
earlier with some programs that use INT 1. The following describes how
to create a command file (FIXINT1.COM) that can be run in your
AUTOEXEC.BAT to prevent this conflict. FIXINT1.COM is not necessary
if you have QEMM 5.0 or later.
NOTE: In the DEBUG examples below, I have placed the characters you will
be typing inside square brackets. When you see [SPACE] in the
examples, you should press the SPACE bar. When you see
[ENTER] you should press the enter key. In all other cases,
type the characters as they appear in the brackets. You should
not type in the brackets that surround these keys.
STEP 1: Go to the directory where DEBUG.COM is located and type:
at the command line. DEBUG should load and give you a message
'File not found' and leave you at a prompt (A Hyphen)
STEP 2: At the prompt type E 0100 and press the ENTER key.
STEP 3: You should get a line the looks similar to the following:
The 4FDF and 00 will be different for your system and can be
ignored. The 0100 must be correct. If not, press ENTER
and go back to STEP 2.
STEP 4: Next we are going to type in seven, two character values and press
the space bar after value. Each time you press the space bar
DEBUG will extend the line and move the cursor.
Below is an example. The values we will be using are
0F 21 C0 0F 23 C0 C3.
4FDF:0100 00. (this is how the line looks when you start)
4FDF:0100 00.0F 00.[SPACE]
4FDF:0100 00.0F 00.21 00.[C0][SPACE]
4FDF:0100 00.0F 00.21 00.C0 00.[0F][SPACE]
4FDF:0100 00.0F 00.21 00.C0 00.0F 00.[SPACE]
4FDF:0100 00.0F 00.21 00.C0 00.0F 00.23 00.[C0][SPACE]
4FDF:0100 00.0F 00.21 00.C0 00.0F 00.23 00.C0 00.[C3][SPACE]
4FDF:0100 00.0F 00.21 00.C0 00.0F 00.23 00.C0 00.C3 00.
Your line should now look like the one above. At this point,
press the ENTER key.
STEP 5: The next step is to verify what we just typed using the DEBUG
unassemble command. At the DEBUG prompt type U L7 and press the
You will get a display that contains the following 5 lines.
4FDF:0100 0F POP CS
4FDF:0101 21C0 AND AX,AX
4FDF:0103 0F POP CS
4FDF:0104 23C0 AND AX,AX
4FDF:0106 C3 RET
STEP 6: Again, 4FDF can be ignored. All other information should look
exactly like what is above. If it does not, go back to STEP 2 and
try this again.
STEP 7: The next step is to tell DEBUG the size. Type
RCX at the DEBUG prompt and press the ENTER key.
You will get 2 lines that looks similar the two below.
At the colon type the number 7 and press the ENTER key.
STEP 8: The final step is to write the data to disk. At the DEBUG prompt
type W and press the enter key.
You should get the following message:
'Writing 0007 bytes'
and the DEBUG prompt. To quit DEBUG press Q and press the
You will now have a file called FIXINT1.COM in the directory
where you started DEBUG. You can now copy it to the
directory where you want it to be located. If you copy it
to the root directory of the drive you boot from, it will be
To use FIXINT1.COM place it in your AUTOEXEC.BAT file. You may
want to place it at the begining to be sure it is run before the
program that is causing the problem. If it will not be located
in your root directory, you may need to specify the full path
in AUTOEXEC.BAT for it to execute correctly. The following line
shows FIXINT1.COM if it is located in the subdirectory C:\UTILITY.
If you are not succesful in creating FIXINT1.COM you may call into
our Bulletin Board service at 213-396-3904. You should download
FIXINT1.ARC and ARCE.COM from directory 45. ARCE.COM is used
to extract FIXINT1's files from FIXINT1.ARC. Your modem should
be set to * bits, No Parity and 1 Stop Bit.
* * * E N D O F F I L E * * *