Msg # 9719  Type:B  Stat:$  To: SPEED @NVPNET  From: PI8NVP  Date: 16-Jul/0018
Subject: SPEEDUP
Bulletin ID: PI8NVP_9719 

                        DOS 2.0 SPEED UP
                        by Henry Ho
(as published in "The Personal Computer Club of Toronto Newsletter"
Volume 1, Number 6   July/August 1983)  - adapted by Jim Knopf

  If you liked "DOS 1.1 SPEED-UP" published in Volume 1 Number 2 of our
Newsletter, you'll like this one too.  I did not write that DOS 1.1
speedup, but it was so good that when I acquired DOS 2.0, I had to figure
out a way to speed it up too. (This method is borrowed from the previous
method). You will find that after the modification, the disk seek time is
much faster and the drive is much quieter.
  DOS uses a set of parameters which consist of an eleven byte table for
its diskette operations. This set of parameters is stored in the ROM BIOS
(Technical Reference Appendix A-41), and is pointed at by the Data Variable
Disk Pointer (INT 1EH).  DOS 1.0 uses also this table.  To
change any of the parameters, you can build another parameter table in the
memory and change the pointer to point at it.  DOS will first read the
parameter table each time before it reads or writes to diskettes.
  The popular DOS speedup routines all accomplish the same thing; change
the parameter table and the disk pointer.
  To modify your DOS diskette, use the DEBUG program on the DOS supplemental
program diskette.  You should work on a backup copy of your original DOS
diskette (single sided).  This modification must be applied to single sided,
9 sector/track only.  Do not use other formatted diskettes because the
locations will be different. (Do not type in the remarks).
PLease note that this modification is unsupported so use it at your own risk.
   Insert your DOS disk (to be modified) in drive A, DOS supplemental disk
in drive B, and type in the following:
A>B:DEBUG
-L 100 0 0 80      ;Load absolute disk sectors 0 to 80H into memory
-E 121             ;Enter command - change memory location
XXXX:0121 DF.EF    ;Change byte DF to EF, a total of 4 times
-E 1AC6
XXXX:1AC6 DF.EF
-E CC71
XXXX:CC71 DF.EF
-E EBAF
XXXX:EBAF DF.EF
-W 100 0 0 80      ;Write memory to disk
-Q                 ;Quit DEBUG
   After you have modified your diskette, exit DEBUG to DOS.  Now you have
to reboot the disk to make the changes effective.  To carry the changes to
a new DOS system diskette, just format with the /S option.  (Jim's note:
it does not seem to be sufficient to just do the SYS command, you really
must FORMAT /S).

C.B.M.S. cmd's >