KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q99008: MS-DOS 6 MEM Command Reports 384K for Adapter RAM/ROM

Article: Q99008
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:6.0
Operating System(s): 
Keyword(s): 
Last Modified: 21-NOV-1999

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft MS-DOS operating system version 6.0 
-------------------------------------------------------------------------------

SUMMARY
=======

The MS-DOS 6 MEM command may display an incorrect value for Adapter RAM/ROM. On
many machines, MEM displays a table similar to the following:

  Memory Type        Total =  Used  +  Free
  ------------------------------------------

  Conventional        640K     126K     515K
  Upper               139K     111K      28K
  Adapter RAM/ROM     384K     384K       0K
  Extended (XMS)     7029K    2781K    4248K
  ------------------------------------------

  Total memory       8192K    3401K    4791K

It is not possible to have 384K Adapter RAM/ROM and a value greater than zero for
upper memory.

MORE INFORMATION
================

Adapter RAM/ROM
---------------

The value specified by Adapter RAM/ROM is calculated as follows:

  1 MB (1024K) minus conventional memory, minus upper memory
  block (UMB) space

Therefore, Adapter RAM/ROM is the sum of the following:

- Excluded UMB space

- Memory used by BIOS and adapter cards

- Expanded memory services (EMS) page frame(s)

However, on machines in which the amount of reported extended memory is below the
1 MB boundary (384K or less), MEM increases the value reported for Adapter
RAM/ROM so that the total memory on the system is a multiple of 1 MB.

NOTE: The amount of extended memory reported is correct.

Definitions
-----------

The upper memory area (UMA) is a range of addresses between 640K and 1 MB
(1024K). This area is also commonly called the reserved address space.

Upper memory blocks (UMBs) are areas in the UMA that EMM386.EXE has reserved for
loading device drivers and terminate-and-stay-resident (TSR) programs high.

Additional query words: 6.00 XMS

======================================================================
Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS600
Version           : MS-DOS:6.0

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.