Re: DOS 3.3 versions

[nparker@cie-2.uoregon.edu (Neil Parker)]

In article <32f3c9f7.1063491@167.152.149.11> drsmooth@relex.com (Edhel Iaur,
Esq.) writes:
>[...]
>That reminds me: I have a disk called "RANDY'S FAVORITE COPY PROGRAMS
>VOLUME  # 2".  The first line in the HELLO program is:
>
>1 POKE 47102,236: REM  SPEED DOS UP
>
>Anybody know if this actually does anything, and how?
>
>The DOS that comes on this disk, interestingly enough, is PRONTO-DOS.
>It could have been transplanted, tho.

I don't have a copy of Pronto-DOS to play with, but if it's anything like
normal DOS 3.3, location 47102 contains the high byte of RWTS motor-on time
count.  The normal value in this location is 216 ($D8).

The motor-on time count is used by RWTS when it first turns on the disk
drive.  It controls how long RWTS waits for the drive to come up to full
speed.  The larger the contents of location 47102, the less time DOS waits
for the disk to spin up.

So yes, I guess this POKE really would cause a slight speed-up.  But
resorting to methods like this strikes me as riding the ragged edge:  DOS
has that start-up delay built in because it NEEDS the delay--you really
don't want to access the drive before the motor is spinning at full speed,
for exactly the same reason that you don't want to calibrate your disk
drive so that it perpetually runs slow.


In summary, I wouldn't trust this POKE--it's trying to gain a slight
performance improvement at the expense of reliability.  Besides, any
improvement you get from it will probably be insignificant beside the
improvement that comes from using a speed-patched DOS like Pronto-DOS.
(Pronto-DOS and other packages like it gain their extra speed by techniques
completely unrelated to this POKE.)

            - Neil Parker
-- 
Neil Parker, nparker@{cie-2,cie}.uoregon.edu, http://cie-2.uoregon.edu/~nparker
     "Evolution is vastly overrated."  -- Ambassador Delenn, _Babylon_5_

Unsolicited commercial e-mail to my address will be discarded unread.