The Concept of Statistics

The RamPak 4GS Statistics Utility offers the user the ability to view the efficiency of the current cache set-up at any time. It will allow the user to view such items as the number of reads, reads to cached blocks (also called a HIT), the percentage of reads to hits (the cache efficiency), the number of buffers allocated to any drive, and how many writes to disk have occurred. And by using the RESET STATISTICS COUNTER TO ZERO feature under the SETTINGS menu along with MANUAL CACHE ALLOCATION, the user can fine-tune the operation of the system.

To use the Statistics Utility, the user should simply boot the system, then go to the SETTINGS menu and select STATISTICS. Then reset the statistic counters to zero, run the application for a period of time, and return to the SHOW STATISTICS dialog box under the FILE menu to view the accumulated statistics. If the percentage of reads to hits is low, then the cache size should probably be increased. If the percentage of hits to reads is close to 100%, you may wish to decrease the cache size, especially if program memory is in short supply. It is recommended that a minimum of 8 blocks and a maximum of 64 blocks be allocated for each drive to be cached. These selections can be made from the MANUAL CACHE ALLOCATION dialog box,also in the SETTINGS menu.

Manual Cache Allocation

This will open the Manual Cache Allocation dialog box, from which you control the use of your installed RAM. The upper portion of the box allows the setting of up to sixteen disk caches, one for each of the possible disk drives serving your Apple IIGS system.A box in the upper left indicates the drive for which a cache is

currently being set (see in the diagram below). This box should be displaying a value between SØD1 and 57D2. This indicates the slot and drive numbers of the drive to be cached, as your Apple IIGS has eight logical slot locations, each of which can address two drives. To the immediate right of this box are up and down arrows

Using the mouse to click on these arrows enables you to change the drive selection. Further to the right is

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