Using Quarterdeck's BUFFERS.COM With MS-DOS 4.0 and Later (76199)

MORE INFORMATION

Look-ahead buffers, introduced in MS-DOS 4.0, allow multiple sector processing when sequential data is read from or written to a disk. Quarterdeck BUFFERS.COM does not support this format.

BUFFERS.COM, prior to QEMM version 6.0, is designed to allow users with QEMM and MS-DOS versions earlier than 4.0 to load system buffers out of conventional memory with the following line in the AUTOEXEC.BAT file:

   loadhi buffers=##
				

This loads the disk buffers into High RAM, also known as Upper Memory Blocks. Buffers created with BUFFERS.COM are in addition to buffers allocated via the BUFFERS= statement in CONFIG.SYS.

With the 6.0 release of QEMM, support for MS-DOS 5.0 was added to BUFFERS.COM and buffers can be loaded high through the AUTOEXEC.BAT in the manner listed above. However, there is less need to use BUFFERS.COM with MS-DOS 5.0 as up to 48 disk buffers can be loaded into the high memory area (HMA) when MS-DOS is loaded high. For example, the following lines in the CONFIG.SYS file will allocate 20 buffers which load with MS-DOS into the HMA:

   device=c:\qemm\qemm386.sys
   dos=high
   buffers=20
				

If more than 48 buffers are in specified using BUFFERS=, all of the buffers allocated by BUFFERS= will be loaded into conventional memory.

Although all versions of BUFFERS.COM continue to be incompatible with MS-DOS versions 4.0, 4.01, and 4.01a, buffers can be loaded into expanded memory (when present) by adding /X to the end of the buffers line in the CONFIG.SYS file. For example, the line below loads 20 disk buffers into expanded memory:

   buffers=20 /x
				

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

Reference(s):

"Quarterdeck expanded memory manager 386," version 5.0 pages 43-44. "Quarterdeck expanded memory manager 386," version 6.0 page 67.