SMARTDRV Cache Status -- What Does the Buffering Value Mean?

• Microsoft Windows operating system versions 3.0, 3.00a, 3.1, 3.11
• Microsoft Windows for Workgroups versions 3.1, 3.11
• Microsoft MS-DOS operating system versions 6.0, 6.2, 6.21

SUMMARY

In MS-DOS, Windows, and Windows for Workgroups, the character-mode display of the status of SMARTDrive has a column for buffering status. The entry in this column can be "yes," "no," or "-" (MINUS SIGN). This article describes the meaning of these entries.

MORE INFORMATION

The following is an example of the printout you receive if you access SMARTDrive from the command prompt by typing "smartdrv" (without the quotation marks) and pressing the ENTER key:

   Microsoft SMARTDrive Disk Cache version 4.0
   Copyright 1991,1992 Microsoft Corp.

   Cache size: 1,048,576 bytes
   Cache size while running Windows: 1,048,576 bytes

               Disk Caching Status
   drive   read cache   write cache   buffering
   --------------------------------------------
     A:       yes           no           no
     B:       yes           no           no
     C:       yes           yes          yes
     F:       yes           yes          -
     G:       yes           no           no

   For help, type "Smartdrv /?"

SMARTDRV.EXE watches each data transfer to determine the need for buffering. If it sees a transfer to an upper memory block (UMB), it may be unable to determine if there is a need for double buffering.

NOTE: The double buffer driver must be loaded for SMARTDRV.EXE to determine if there is a need for buffering. If the double buffer driver is not loaded, all entries in the buffering column read "no." The double buffer driver is loaded from the CONFIG.SYS file. The following is a sample line to install the double buffer driver:

   DEVICE=C:\WINDOWS\SMARTDRV.EXE /DOUBLE_BUFFER

You can force the double buffer driver to load even if SMARTDRV.EXE decides that it is unnecessary. Adding a PLUS SIGN (+), as in the following example, forces the double buffer to load:

   DEVICE=C:\WINDOWS\SMARTDRV.EXE /DOUBLE_BUFFER+