COM01J.DOC

Here are the addresses in COM01.SYS for OS/2 1.30 to patch to turn it
into a driver for serial devices other than COM1 and COM2.

As delivered, COM01.SYS supports COM1 (which I'm calling device A) and
COM2 (which I'm calling device B).

Copy COM01.SYS to COM01J.SYS or whatever name you like, then patch
COM01J.SYS using the following table as a guide.

The OS/2 PATCH utility can do the job nicely.

Address Type As delivered What is it

0111 Char '1' Character for device name of device A
012B Char '2' Character for device name of device B
0305 Word 0000 Port number (0..3) of device A
030E Word 0001 Port number (0..3) of device B
17FD Word 03F8 I/O address for device A
1807 Word 02F8 I/O address for device B
184B Byte 00 Port number (0..3) of device A
189B Byte 00 Port number (0..3) of device A
17FA Byte 04 IRQ level of device A
1804 Byte 03 IRQ level of device B

Suggested values to support COM2/COM3,
which I use as my only driver since I only have 3 ports
and the mouse driver handles COM1.

Address Type Change to What is it

0111 Char '2' Character for device name of device A
012B Char '3' Character for device name of device B
0305 Word 0001 Port number (0..3) of device A
030E Word 0002 Port number (0..3) of device B
17FD Word 02F8 I/O address for device A
1807 Word 03E8 I/O address for device B
184B Byte 01 Port number (0..3) of device A
189B Byte 01 Port number (0..3) of device A
17FA Byte 03 IRQ level of device A
1804 Byte 05 IRQ level of device B


This list was originally provided for OS/2 1.1 by

Wayne Conrad
Phoenix Control Systems
(602) 278-8737


I have updated it for OS/2 1.3 based on searching for
similar strings and assembly code.

Joel Apisdorf
11649 N. Shore Drive, #2B
Reston, Virginia 22090
(703) 437-1837

(ADVERTIZING PLUG)
I am an independent consultant, specializing in device drivers,
graphics, and OS/2. Feel free to send business my way!