Incorrect SMARTDrive BufferSize Setting Hangs System (94604)

SUMMARY

SMARTDrive version 4.0, the disk-caching utility supplied with Windows, has a switch, /b:BufferSize, that enables you to change the default size of SMARTDrive's buffer. If this switch contains an invalid entry, the result could hang the system during startup, requiring a boot (system) disk to start the computer.

MORE INFORMATION

SMARTDrive's buffer is separate from the cache. Data is initially transferred to the buffer's memory, then written to the cache in portions, as determined by the /e:ElementSize switch. The default element size is 8192 bytes.

The BufferSize setting is measured in bytes and has a default value of 16K. Page 540 of the "Microsoft Windows User's Guide" states that the valid values for BufferSize can be any multiple of the ElementSize setting. The guide provides no upper limit. However, there is an upper limit on the BufferSize setting based on how much memory is available in the upper memory area (UMA) or in conventional memory.

The valid entries for ElementSize and BufferSize are as follows:

   If This Value
   Is Used for /e        Use This Value for /b
   ------------------------------------------------------------------

   /e:1024               Multiples of /e up to and including /b:16384
   /e:2048               Multiples of /e up to and including /b:32768
   /e:4096               Multiples of /e up to and including /b:57344
   /e:8192               Multiples of /e up to and including /b:57344

If you attempt to use any other values, you may experience one of the following problems:

The system stops responding (hangs).
The error message "Sector not found reading drive x" (where "x" is the drive being accessed after SMARTDrive is loaded) appears.
The size of SMARTDrive's buffer will not match the BufferSize setting.

For additional information about SMARTDrive, refer to pages 539-541 in the "Microsoft Windows User's Guide."