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From: mknox@NGP.UTEXAS.EDU.UUCP
Newsgroups: mod.computers.68k
Subject: Re: Answers! (disk track buffering)
Message-ID: <8606130055.AA29139@ngp.UTEXAS.EDU>
Date: Thu, 12-Jun-86 20:55:45 EDT
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Posted: Thu Jun 12 20:55:45 1986
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[Still waiting to hear anything about the 1.3 C compiler problem.  My latest
ploy (since tech support has not yet been any help), the DRI sig on CompuServe]

A suggestion for a slight improvement:  Your idea to set a timer to let one
second elapse (to handle possible disk changes, without relying on a "open
door" signal) is fine.  But if you can get regular timed interrupts like
that, don't unconditionally mark the track buffer invalid after one second.
Instead, after each interrupt, check the READY signal from the drive (they
ALL have that).  If it is not present (NOT READY), *then* mark the track
buffer invalid.  That way you still get the benefit of the buffering on
the startup for new tasks.

One further note:  if you put in the above, then ONLY mark the buffer invalkd
on NOT READY.  In other words, don't reset it unconditionally on WARM BOOT.

					mknox