Contents of the DFA13.DOC file
DFA13 - DOS File Accelerator v1.3 20-Nov-86, S.H.Smith
Public domain material,
for personal use only.
DFA13 is a small resident utility that can "accelerate" file access in
DFA13 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 DFA13 gets data BEFORE it is needed.
DFA13 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 DFA13 is loaded in memory, the DFA13 command will enable and
disable file acceleration. This allows you to turn off the effects
of DFA13 for comparison purposes.
DFA13 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!
Another utility program, DFAMON is also provided. This program can be
run in one side of DoubleDOS, while DFA13 is loaded in the other side.
When running, DFAMON lists all of the active input/output files, the
amound of data in the acceleration buffer, and the ratio of accelerated
to physical reads.
Written by Samuel H. Smith, 24-may-86
Assemble with MASM v4.0
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 DFA13. This can be patched with DEBUG.
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 DFA10
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.
21-Nov-86 v1.3 Added additional status accumulators. Wrote new
DFAMON program to monitor file acceleration status