Message-ID: <646@burl.UUCP>
Date: Tue, 26-Feb-85 17:23:15 EST
Article-I.D.: burl.646
Posted: Tue Feb 26 17:23:15 1985
Date-Received: Wed, 27-Feb-85 20:54:45 EST
Distribution: net
Organization: AT&T Technologies, Burlington NC
Lines: 19

I have been trying to get some information on how to communicate directly
with my disk drives.  I found one very good book called 'Beneath Apple Dos'
which tells most of the gory details.  It gives all the right locations to
punch to do reads and writes, and even gives examples of code which will
perform the writes in the required 32 cycles/byte.  However, when they get
to seeking to a given track, all they say is that turning the arm stepper
motor phases on in sequence from 1-4 moves it one way and 4-1 it moves it the
other.  It then says that the timing of these phases is critical and they
recommend using rwts to do it.  Period.  NO indication of what is critical,
how long the phases must be on and off, and so forth.  (If rwts can do it
consistently, it can't be that damned difficult!!).
I want to be able to run completely stand-alone, without DOS in the system
at all (this makes calling rwts rather difficult).  Has anyone out there had
any experience with this (or just knows the magik numbers?).

	thanks, all,

		geoff sherwood
		burl!geoff