To get more information on programming for OS/2, especially for hardware I/O, visit the sites listed below: www.edm2.com
Look through back issues of articles published on hardware I/O and device drivers.
Also offers online classes for programming for OS/2.

http://avenger.mri.psu.edu/os2page.html
Information and source code on how to access I/O ports in OS/2.

http://femto.ssp.ameslab.gov
Contains OS/2 Warp Programming information for digital I/O
and GPIB devices.

To get information on interfacing to a PC or to get information on digital I/O products, visit the sites listed below: http://shell.rmi.net/~hisys/parport.html
IBM Parallel Port FAQ/Tutorial.

http://www.senet.com.au/~cpeacock/
Craig Peacock's Interfacing the PC. Online tutorial to interface any
device to the parallel or serial ports.
Many additional links to other sites about interfacing to computers.

http://www.industry.net/indcompsrc
Industrial Computer Source. Industrial computers and data acquisition products.

http://www.acces-usa.com
Acces I/O Products. Carries low-cost digital I/O products.

To get more information on programming for OS/2 using REXX visit the sites listed below: http://rexx.hursley.ibm.com/rexx/
Main REXX site.

http://www.vispro.com/
Visual programming for OS/2 using REXX. Hockware's Vispro/REXX site.

Helpful books about programming for OS/2 using REXX: Teach Yourself REXX in 21 Days. Schindler&Schindler, SAMS, ISBN 0-672-30529-1

REXX Reference Summary Handbook, Dick Goran, CFS Nevada, ISBN 0-9639854-3-4
http://www.cfsrexx.com

OS/2 REXX, From Bark to Byte, Document Number GG24-4199-00, read online at:
http://publib.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/GG244199/contents