[comp.sys.atari.st] Help! TOS, BIOS, XBIOS, etc. help needed.

hi2cah@sdcc13.ucsd.EDU (John Ogawa) (04/22/87)

<< I live to be eaten! Thank Y

I am trying to write an all-in-one desk accessory to set screen
colors, write verify, flush rs232 buffers, coldboot, and set the sek
rate. OK, so far so good. I've got the interface alright, and I know
the easy stuff, setting the screen and the write verify and the
rs232 flush. The problem is that I can't figure out a) how to force
a boot (hard or soft) after clearing MEMVALID and MEMVAL2, and b)
how to get the disk drive to accept a seek rate change. On the
former, I'm working in C, MWC 2.0 to be exact, so I'd appreciate any
answers be reachable in C. Do I just call a routine set at $0501E ??
  The latter is more of a mystery. According to Abacus Internals and
MWC documentation, $440 contains the seek rate, 0=6 msec, 1=12 msec,
2=2 msec, and 3=3 msec. OK, so I set it to 2 msec and got out and
ran my disk on a large file. Sounds the same to me. A check on the
seek rate using Private Eye Desk Acc (nice!) showed 2 msec. I didn't
hear a change. Anybody know what's going on? I found some
interesting stuff in BIOS around $06800, is the answer there?
   I have a program called DISKDIAG that checks disk performance and
allows you to set the verify and seek rate. I can hear the
difference there. Sounds much higher at 2 msec (not surprising
:-)!). Is the author(s) around?
   Also, on a related note:  while trying to find info about the
seek rate, I found that you could change the stepper motor rate as
well. My question is:  what changes come from changing the stepper
motor rate, and are they worth it/dangerous?? While I'm asking that,
is there any REAL advantage to changing the seek rate or any REAL
dangers?
   Thanks much for any light anyone can shed on any of these
subjects :-)!
   Please note the address on the bottom of this posting and try to
send replies there. I'd rather read 'em on that account. Thanks.

John Ogawa

GEnie: TUSHIE
NET: ps136sag@sdcc13.ucsd.edu <or> ...ucbvax!sdcsvax!sdcc13!ps136sag

ps> I'll summarize answers to the net if people want.

pps> I'll give the program to Jim Turner when I'm done if it's any
good.