Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!udel!mmdf
From: wjb@cogsci.cog.jhu.edu
Newsgroups: comp.os.minix
Subject: Re: IDE disks
Message-ID: <44850@nigel.ee.udel.edu>
Date: 17 Feb 91 02:37:44 GMT
Sender: mmdf@ee.udel.edu
Lines: 62



I wrote various stuff about possible problems with IDE.

Norbert wrote:
>These points are all possible, I suppose.  I would add that my Conner CP3104
>works flawlessly under Minix, while Spinrite seems unable to do anything at
>all with the drive.

I said:
	works with SpinRite -> works with Minix
this does not mean
	works with Minix -> works with Spinrite

	Depending on which "version" of SpinRite II you have, it may or may
not be able to deal with an unusual numbers of sectors per track.  Do you
know what the physical characteristics of your drive are?  I'm curious as to
why it doesn't work with SpinRite.

>I disclaim knowledge of the characteristics of any
>other IDE drive, although it would surprise me if they didn't include some
>sort of compatibility with the WD standard (e.g. the CP3104 can be set up to
>look like an old MFM drive, 17 sectors per track - I don't run it that way).

	Be careful with "sector-translation" modes.  RLL and ARLL controllers
often have the capability to provide translation modes to make them appear
to have 17 sectors per track.  I've tried to find out from vendors whether
this is implemented via the BIOS code or whether it is done in hardware.
Unfortunately, in at least one instance when I called the manufacturer their
technical support people couldn't answer the question.  Given that DOS rules
the PC world and implementing it via code in the BIOS is easier then doing it
in hardware.  Well, ...  Since Minix bypasses the BIOS, translation
implemented that way wouldn't help.  How Conner implemented it is unknown to
me.

>I highly recommend the CP3104, which is physically tiny, quiet, capacious,
>and very fast.  I believe prices have come down to <$500 mail order, which I
>think is reasonable for 104 Mb.

	I'm glad that it worked for you.  Unfortunately, I know either too
much or too little to feel comfortable making any kind of blanket statement
about IDE.  The questions I would ask a vendor would be:

	Is it Western Digital register compatible?
		If no forget it.
	Does it have a fixed number of sectors per track?
		If no you would have to waste space.
	What are its PHYSICAL drive characteristics?
	In particular how many cylinders?
		(DOS has problems with more then 1024 cylinders.  You
		could use a translation mode, but this would probably confuse
		Minix if the mode was implemented in the BIOS.)
	What is your return policy? 1/2 :-)

As you can probably tell by now, I'm something of a pessimist.  I think the
low cost of IDE drives is great.  I just wish I could be sure about
compatibility.  Fortunately, I'm not in the market right now for more storage
and by the time I am I expect things to have stabilized or my ignorance to
have been rectified.  Conner looks like a company I would call to get answers
to my questions.

				Bill Bogstad