Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!hp4nl!philmds!nlgvax!johan
From: johan@nlgvax.UUCP (Johan Stevenson)
Newsgroups: comp.os.minix
Subject: Re: Minix - Atari Megafile 60 problems (continued)
Message-ID: <209@nlgvax.UUCP>
Date: 16 Feb 89 21:15:28 GMT
References: <8899@louie.udel.EDU>
Reply-To: johan@nlgvax.UUCP (Johan Stevenson)
Organization: Philips Research Geldrop
Lines: 24

In article <8899@louie.udel.EDU> PRINS%HLERUL5.BITNET@cunyvm.cuny.edu (Ryko Prins, CRI, Leiden, Netherlands) writes:
	>My Mega 2 can only access the Megafile 60 when I have just powered up,
	>after some minutes I get unrecoverable disk errors.

Are more people experiencing problems with Megafile 60?

	>By the way, did you know the hard disk driver p o l l s for interrupts?
Yes, each disk request generates 7 (8 for the Supra I believe) interrupts.
6 interrupts come normally immediately, so I wait a few cycles.
A normal interrupt costs hundreds/thousands of instructions. This way
it takes only 10 or so.
	>Which would take account for the many system CPU seconds you see being used in the
	>CNTRL-ALT-PF1 display for process HARDWARE (if I am correct).
No. Since that counter increases as well if you have no hard disk
at all.
	>Anyway, I guess it
	>costs a lot of system performance the way it is implemented.
No. This is by far the cheapest way.
	>Well, I don't have much time for it, but I think I should take a serious look
	>at the Minix-ST hard disk driver now, which will take some time, unless there
	>are other people with the same problems, so we could share some work.
I always like improvements.
--
Johan W. Stevenson	johan@pcg.philips.nl		Philips Research