Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!gatech!udel!mmdf
From: PRINS%HLERUL5.BITNET@cunyvm.cuny.edu (Ryko Prins, CRI, Leiden, Netherlands)
Newsgroups: comp.os.minix
Subject: Minix - Atari Megafile 60 problems (continued)
Message-ID: <8899@louie.udel.EDU>
Date: 16 Feb 89 09:41:45 GMT
Sender: usenet@udel.EDU
Lines: 29

Problem:

My Mega 2 can only access the Megafile 60 when I have just powered up,
after some minutes I get unrecoverable disk errors.
If I recompile my system using the TRACE option for the driver it does some
disk access, but after that a kernel panic is generated and everyting stops.
Hardware problems are ruled out; both TOS and Aladin work fine on the same
partitions.

Hypothesis:

There is a timing problem in the Minix disk driver.
The Megafile 60 is the only drive in the Atari line with an average seek time
of 61 Ms compared to 65 Ms on all other Atari drives, so I suspect some diffe-
rences in timing.
If the drive is cold, timing could be slightly different, (just within the
margins in which Minix can operate) than if the drive is warm.
By the way, did you know the hard disk driver p o l l s for interrupts? 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). Anyway, I guess it
costs a lot of system performance the way it is implemented.

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.

Any comments? Dou you think I am thinking along the right line?

                                                Greetings, Ryko Prins.