Size of Expanded Memory Pool Adjusted (76916)

The information in this article applies to:
    Microsoft MS-DOS operating system 5.0

This article was previously published under Q76916


Upon booting your machine, EMM386 may display the following message:

Size of Expanded memory pool adjusted
This message indicates that EMM386 has adjusted the amount of expanded memory it will emulate from the machine's XMS memory.

The above message indicates one of two situations:
    The amount of XMS memory specified by the RAM switch on the EMM386 device line is not a multiple of 16, so EMM386 adjusted the number to be a multiple of 16. -or-

    The amount of XMS memory specified by the RAM switch on the EMM386 device line is not available, so EMM386 adjusted the amount of XMS memory to reflect what is available.


When the RAM switch is included, EMM386 sets aside the indicated amount of XMS memory and uses it to emulate expanded memory. The amount of XMS memory EMM386 sets aside is determined by the number (or lack thereof) placed before the RAM switch in the EMM386 device line in the CONFIG.SYS file. This number should be referred to in kilobytes (K). Because EMM386 sets aside memory in 16K blocks, the number should also be referred to in multiples of 16. For example, the following line sets aside 1024K (1 MB) of XMS memory to be emulated as expanded:

device=c:\dos\emm386.exe 1024 ram

Note: EMM386 will also set aside an additional 108K of memory above and beyond the amount specified before the RAM switch. When specifying the RAM switch (or with no switch at all), EMM386 creates a 64K page frame in the upper memory area (UMA). The actual amount of extended memory used will be 64K plus overhead. The overhead represents tables that EMM386 sets up to emulate expanded memory. The size of these tables depends on the amount of expanded memory EMM386 has been asked to emulate. An approximate range of the overhead memory is between 44K and 100K.

If no number is included before the RAM switch, EMM386 will by default emulate 256K of expanded memory.

Modification Type: Major Last Reviewed: 11/26/1999
Keywords: KB76916