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Q43895: "Device Unavailable"; PS/2 SETUP Doesn’t Recognize COM2 Port

Article: Q43895
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S890424-38 B_BasicCom | mspl13_basic
Last Modified: 15-DEC-1989

A "Device unavailable" error may occur when a QuickBASIC program
attempts to OPEN "COM2:" and the IBM PS/2 system SETUP utility hasn't
been configured or can't be configured to recognize COM2.

This problem has been reported with the IBM PS/2 Model 30 computer.
The SETUP utility doesn't make provisions for a second communications
port. Therefore, the BIOS data area RS232_BASE does not contain the
proper information that QuickBASIC is looking for. A good example is
an internal modem card configured as COM2 that is put in the PS/2 but
not recognized as an actual communications port. QuickBASIC looks in
the BIOS data area to see if there is a COM2 port to use and doesn't
find the proper information. This problem is caused by the PS/2 Model
30 (and possibly other models) and is not a problem with QuickBASIC.

The RS232_BASE area can be set with the proper COM2 information using
a simple QuickBASIC program. This program can be found in this
Knowledge Base by querying on the following words:

   COM2 and Bad Filename and QuickBASIC

This information applies to Microsoft QuickBASIC Versions 4.00, 4.00b,
and 4.50, Microsoft BASIC Compiler Versions 6.00 and 6.00b, and
Microsoft BASIC PDS Version 7.00.

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