Stacker Coprocessor Card with MS-DOS 5.0 and EMM386.EXE (75129)

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

This article was previously published under Q75129


STAC Electronics manufactures a coprocessor card that works in conjunction with the Stacker Disk Compression Software Utility. Some additional steps are necessary when you use a Stacker Coprocessor Card with MS-DOS version 5.0 and EMM386.EXE.


Stacker is a disk compression utility used to obtain more space on a hard drive. A Stacker Coprocessor Card can be used in addition to the stacker software to increase the amount of file compression provided by this software. The card is also used to speed up the stacker compression/decompression process and allows for a smaller "stacker" device driver. The Stacker Coprocessor Card does NOT emmulate a "math-coprocessor".

The card is addressed in the upper memory area and does not deal with the high memory area. Therefore, DOS can be loaded high without problems from the coprocessor card. It is very similar to a network card where the range it uses in memory must be excluded from the upper memory area.

When the Stacker card is used, a driver for it can be found in the CONFIG.SYS file, as follows:
   device=[drive:][path]\ /b=<address> c:\stacvol.000
(Note: The default for the address is CC00.)

If EMM386.EXE is loaded in CONFIG.SYS, the range the coprocessor card uses must be excluded. The "device=" line above indicates the starting range. From this point, refer to page 17 of the Stacker manual for a table showing proper memory ranges for that card (usually the starting address + 16K). The EMM386.EXE line should then be modified accordingly, as follows:
   device=c:\dos\emm386.exe X=<xxxx-yyyy>
(Note: The default is X=cc00-cfff.)

The product included here, Stacker, is manufactured by a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

Modification Type: Major Last Reviewed: 11/21/1999
Keywords: KB75129