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1986-06-21
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DFA11 - DOS File Accelerator v1.1 3-Jun-86, S.H.Smith
Public domain material,
for personal use only.
DFA11 is a small resident utility that can "accelerate" file access in
many programs.
DFA11 predicts when your program will want to read from a file and
reads the data into a buffer before it is asked for. This is the
opposite of a "cache" type program. A cache keeps data AFTER it has
been used DFA11 gets data BEFORE it is needed.
DFA11 can speed up Turbo Pascal include file compiles by 10%. The
JANUS/ADA compiler is speeded up by 25%. The LOGITECH base Modula/2
compiler is speed up by over 30%.
Programs that read and write small blocks can be speeded up by as much
as 40% due to reduced head seeking. Great for use with "ARC".
When DFA11 is loaded in memory, the DFA11 command will enable and
disable file acceleration. This allows you to turn off the effects
of DFA11 for comparison purposes.
DFA11 has been tested on DOS 3.1 with both floppy and hard disks. This
program should be loaded AFTER multi-tasking utilities.
WARNING: This program will not work properly if loaded BEFORE a multi-
tasking utility such as DoubleDOS or DESQview!
WARNING: This program goes between your programs and DOS and had the
potential of causing data loss. Make sure you have made a backup
before you try this program. Use at your own risk!
Written by Samuel H. Smith, 24-may-86
Assemble with MASM v4.0
SPECIAL LOCATIONS
=================
CS OFFSET DECRIPTION
--------- ----------
103 This word sets the size of the buffer area. Sizes
from 800h to 3000h seem to work best. The maximum
size is FC00h. This can be patched with DEBUG.
105 This word sets the maximum read size that will trigger
buffering on a file. Smaller read sizes will always
trigger buffering. Larger sizes indicate that your
program is already buffering and does not need any
help from DFA11. This can be patched with DEBUG.
107 This word is a runtime counter of how many reads
have been accelerated since DFA11 was started. Use
DEBUG or XRAY to monitor this location.
109 This word is a runtime counter of DOS reads that
have been made in preparation for file acceleration.
RELEASE HISTORY
===============
24-May-86 v1.0 This was the initial release.
25-May-86 v1.0a The acceleration counters were added.
A check was added for CTRL-BREAK. in 1.0 DFA11
would go to sleep when CTRL-BREAK was used to
abort a program. --THIS VERSION HAS TROUBLE WITH
MULTI-PROCESS/SUB-PROCESS AND IS REPORTED TO TRASH
WRITES ON DOS 2.1
29-may-86 v1.1 Revised for assembly with MASM 4.0
Added enable/disable function.
Compile and Link Instructions
=============================
dfa11.obj: dfa11.asm
MASM dfa11,dfa11,nul,nul/z/t
dfa11.com: dfa11.obj
LINK dfa11;
EXE2BIN dfa11 dfa11.com
DEL dfa11.exe
DEL dfa11.obj