Qmodem Reboots the Machine in Enhanced Mode

• Microsoft Windows operating system versions 3.0, 3.0a, 3.1, 3.11

SYMPTOMS

When you are using the Forbin Project Qmodem versions 4.0 and 4.5 MS-DOS communications program under Microsoft Windows 3.0 or 3.1 in 386 enhanced mode, the system reboots.

CAUSE

This problem occurs because Qmodem 4.0 and 4.5 attempt to use expanded memory, but do not check for an error return when obtaining the LIM 3.2 expanded memory page frame address. On machines where no LIM 3.2 compatible page frame is available, Windows returns an error. Qmodem ignores the error, and attempts to map data into a nonexistent expanded memory page frame address.

WORKAROUND

To work around the problem, do one of the following:

• Create a .PIF file that specifies a 0 (zero) limit for EMS memory in the Advanced Options dialog box; this disables EMS for the MS-DOS command prompt under Windows, which allows Qmodem to run properly.
• Rearrange hardware adapters in the machine to free a 64K contiguous area in the upper memory area (UMA) (the area from A000 to EFFF hexadecimal).