Memory Conflict Occurs Immediately After Upgrading to 6.2 (105789)
The information in this article applies to:
• Microsoft MS-DOS operating system 6.2
• Microsoft MS-DOS operating system 6.21
• Microsoft MS-DOS operating system 6.22
This article was previously published under Q105789
After you upgrade to MS-DOS 6.2x, your system may stop responding (hang) or
encounter other problems related to memory management or memory conflicts.
This problem occurs when you have existing problems in your upper
memory area (UMA) that are now uncovered in the boot process due to
changes in EMM386.EXE versions 4.48 and 4.49.
The problem occurs during the boot process because EMM386.EXE now fills the
upper memory blocks (UMBs) it believes are free with zeros (often called
"zeroing out") to better determine whether something is already there. In
the past, when EMM386.EXE created a UMB, it would place a copy of whatever
used to be in that memory region in the UMB. Therefore, if you have a
memory conflict, you don't notice it until something is actually loaded
into that UMB and overwrites the ROM code. EMM386.EXE 4.48 and 4.49 fills
the apparently free UMBs with zeros rather than copying the ROM code into
the UMB. Using this design, the upper memory conflict is likely to be
noticed right away.
To correct this problem, do the following:
• If your system hangs, reboot your computer and press the F5 key
when the "Starting MS-DOS..." prompt is displayed.
• Use MS-DOS Editor to edit your CONFIG.SYS file.
• Delete or remark out the DEVICE command for EMM386.EXE.
• Save the CONFIG.SYS file and exit MS-DOS Editor.
• Reboot your computer to ensure you are using a stable memory
• Run MemMaker.
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