Faast-3 Reference Manual Addendum # 1

Memory Management on PCs

Effective with Release 3.3D, revised for Release 3.3F and subsequent
1. Overview.

Starting with release 3.3D, Faast-3 for PCs incorporates improved memory management, more nearly like that found on large computer systems. The advantage to users is that Faast-3 loads into memory and begins executing more quickly. Necessary memory space is created after loading, instead of being built-in.

Prior PC versions of Faast-3 contained fixed-length blocks of memory into which all data and equation space must fit. New PC versions of Faast-3 now obtain necessary memory space, up to the maximum, by requesting memory from the operating system, and/or using extended memory, and/or using a "virtual memory swap file" (meaning disk space is used to augment physical extended RAM memory space).

The purpose of this memorandum is to familiarize users with those things they might do to facilitate the memory management process and speed-up execution times with minimum consumption of disk space.

2. Low Memory Versions of Faast-3 (releases before 3.3F).

The low memory versions of Faast-3 (order codes PCD [demo], PCS [small], and PCL [large] prior to release 3.3F) all requested low memory from the operating system (DOS or Win-x). If the amount of available memory was not enough, then those versions of Faast-3 would use the amount that was available, and show that amount on the sign-on screen. Effective with Release 3.3F, the above Faast versions function the same as the "Extended Memory" versions, see below.

User Actions (low memory releases prior to 3.3F): Users with the above versions of Faast can increase the amount of available memory by not loading programs called TSRs, which stands for "terminate and stay resident." An example of a TSR is the MS-DOS PRINT utility, which occupies memory even when it is not printing anything. If you have enabled the use of what are called "upper memory blocks" (UMBs), you may configure your system to "load-high" some device drivers and portions of DOS, thus freeing-up some low memory. Use the MS-DOS MEM utility (DOS version 5 and higher) or CHKDSK (older DOS versions) to determine the amount of available memory and observe how increases in available memory increase the available space within Faast. Win- systems generally optimize memory space without user action.

3. Extended Memory Versions of Faast-3 (all PC versions, release 3.3F and later).

Program Actions. The extended memory versions of Faast-3 (order codes PCE, PCM, PCJ etc. prior to release 3.3F and all PC versions at 3.3F and later) examine the size of available extended memory and then check for an existing virtual memory swap file. The following actions are taken:

User Actions. If the amount of available space reported by Faast is less than the data space maximum for the version you are using (and if you need the extra space), you can do one or all of several things:
4. How to Create a Larger Swap File.

Beginning with Faast-3, release 3.3D, we provide a special program for creating a virtual memory swap file of sufficient size for running Faast-3 in extended memory (for cases where the extended memory is not sufficient to run without a swap file). This program is called F3SWAPSZ and is provided with Faast-3 PC extended memory versions larger than JUMBO.

Each copy of F3SWAPSZ is sized to match the copy of Faast-3 with which it is issued, and produces a swap file size of at least 3 megabytes. To create a swap file for Faast to use, simply run F3SWAPSZ from the DOS-prompt:
     C> F3SWAPSZ           [return] 
If you receive a new version of Faast-3 for extended memory (larger than JUMBO), you will receive a new version of F3SWAPSZ to match. Avoid using an older, wrong-size copy of the F3SWAPSZ program.

If you are short on disk space, you may delete the swap file when Faast is not in use, and create it again before using Faast.

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Copyright (c) 2006 Faast Software. All rights Reserved.