Microsoft KB Archive/141953

How RAM Cache Works on a Macintosh

PSS ID Number: Q141953 Article last modified on 11-14-1997

6.x 7 7.01 7.10 7.5

MACINTOSH

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= SUMMARY =

This article explains how disk cache (or RAM cache in System 6) works.

= MORE INFORMATION =

Disk cache is a portion of memory reserved for frequently accessed information that your Macintosh would ordinarily have to read from the hard disk. Disk caching allows your computer to access this information quickly from RAM.

Note that memory set aside for the disk cache will not be available for other programs.

In System 7, the Disk Cache option is always on. You can set the cache size from 32K up to a megabyte (MB) or more with the Cache Size box in the Memory control panel. Apple recommends a disk cache size of 128K-256K for System 7. If you frequently access large files or programs from floppy disk a cache size of 348K may improve performance. Changes made in the Cache Size box will only take effect when you restart the Mac.

Accessing the Disk Cache Option
If you are using System 7, use the following steps:


 * 1) On the Apple menu, click Control Panels.
 * 2) Select the Memory control panel.

If you are using System 6, double-click the General icon in control panel.

Determining the Size of Ram Cache
If you are running MultiFinder, set 32K of cache for each MB of RAM installed on your Macintosh. The maximum under MultiFinder is 348K for each megabyte installed on the Macintosh. Changes made to the cache size will only take effect when you restart the Macintosh.

If you are not running MultiFinder, the Cache size should equal 25 percent of your total RAM.

Additional query words: number mac multi finder ram cash 6.0 6.0.2 6.0.3 6.0.4 6.0.5 ====================================================================== Keywords : kb3rdparty kbenv Version : 6.x 7 7.01 7.10 7.5 Platform : MACINTOSH ============================================================================= Copyright Microsoft Corporation 1997.