MEM/C Reports Zero Bytes with MOUSE.EXE Loaded High

MORE INFORMATION

The Microsoft Mouse driver version 9.x and 10.0 can load into upper memory automatically even if the DOS=UMB line is not present in the CONFIG.SYS file.

If the DOS=UMB line is present in the CONFIG.SYS file, memory usage in the upper memory area is reported correctly by the MEM /C command.

Steps to Reproduce Problem

1. Boot your computer with the following CONFIG.SYS and AUTOEXEC.BAT files:

         CONFIG.SYS
         ----------------------------
         DEVICE=C:\DOS\HIMEM.SYS
         DEVICE=C:\DOS\EMM386.EXE RAM
         DOS=UMB
   
         AUTOEXEC.BAT
         ------------------
         C:\MOUSE\MOUSE.EXE
   						

2. Type "mem /c" at the MS-DOS command prompt. The memory used by the mouse driver is reported correctly, as in the following sample report:

         Name        Total     =        Conventional   +  Upper Memory
         -------------------------------------------------------------
         MOUSE       25,328 (25K)       272 (0K)          25,056 (24K)
   						

3. Remove the DOS=UMB line from the CONFIG.SYS file and then restart your computer.
4. Type "mem /c" at the MS-DOS command prompt. The memory used by the mouse driver is reported incorrectly, as in the following sample report:

         Name        Total     =        Conventional   +  Upper Memory
         -------------------------------------------------------------
         MOUSE       272 (0K)           272 (0K)          0 (0K)