Microsoft KB Archive/89788

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SMARTDRV /S Output Defined

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Q89788

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The information in this article applies to:


 * Microsoft Windows versions 3.1, 3.11

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SUMMARY
SMARTDrive 4.0, which is included with Windows 3.1, is able to report information about the performance of SMARTDrive. Typing in the command SMARTDRV /S reports cache hits, misses, element size, and disk caching status. This information indicates the effectiveness of SMARTDrive.

MORE INFORMATION
Loading SMARTDrive (SMARTDRV.EXE) at the command line by typing

"smartdrv.exe 2048 2048" and then typing

"smartdrv /s" provides information similar to the following:

  Room for 256 elements of 8,192 bytes each There have been 8,980 cache hits and 1,966 cache misses

Cache size: 2,097,152 bytes Cache size while running Windows: 2,097,152 bytes

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

DEFINITIONS
The following information defines the output of each line in SMARTDRV /S.

Room for 256 Elements of 8,192 Bytes Each
The number of elements is modified depending upon the specified cache size and the element size. In this case, 2,097,152 (the specified cache size) divided by 8,192 (the element size) is 256 (the number of elements). Therefore, there are 256 elements, each containing 8,192 bytes. Element size is the number of bytes that will be moved at one time by SMARTDrive.

The number of elements reported can only be modified by changing the element size or the cache size. The number of elements cannot be modified directly. Information on how to change the cache size and element size can be found on page 539 of the &quot;Microsoft Windows User's Guide&quot; for version 3.1.

There Have Been 8,980 Cache Hits and 1,966 Cache Misses
The number of hits indicates how many times an element has been found in the cache before going to the hard disk. The number of misses indicates the element was not found in the read cache and a hard disk access occurs.

Generally a larger specified cache size results in a higher hit-to-miss ratio, although this depends on the type of usage. Because the cache size is larger, more data will be found in the cache and should result in a higher amount of hits. Note that allocating too much memory to SMARTDrive can cause memory problems because there may not be adequate memory for other programs.

Cache Size: 2,097,152 Bytes, Cache Size While Running

Windows: 2,097,152 Bytes
Cache size is determined by the number of elements multiplied by the number of bytes in each element. In the above example, 256 (elements) multiplied by 8,192 (number of bytes in each element) is 2,097,152.

Disk Caching Status
This reports the caching status of each drive (read cache, write cache). It also reports buffering of each drive. For each drive that is being cached, it can have one of three values in the buffering column:

"yes, no, or -" &quot;Yes&quot; indicates that double buffering is needed. &quot;No&quot; indicates that buffering is not needed. &quot;-&quot; indicates that SMARTDrive has not yet determined the necessity of double buffering. If the buffering column has all no's in it, the double-buffer driver is unneeded.

In most cases, double buffering is not needed. If it is determined that double buffering is needed and Windows 3.1 Setup did not install it, see page 541 of the &quot;Microsoft Windows User's Guide&quot; for information about installing SMARTDrive in the CONFIG.SYS file with double buffering.

For more information about SMARTDrive, see page 537 of the &quot;Microsoft Windows User's Guide&quot; and page 252 of the &quot;Microsoft Windows Resource Kit&quot; manual.

Additional query words: 3.10 3.11 optimize smart drive SMARTDRV

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Issue type :

Technology : kbWin3xSearch kbWin310 kbWin311