Path: utzoo!attcan!uunet!know!sdd.hp.com!caen!math.lsa.umich.edu!math.lsa.umich.edu!hyc
From: hyc@math.lsa.umich.edu (Howard Chu)
Newsgroups: comp.os.minix
Subject: Re: minix ST 1.5 patch 3
Message-ID: <1990Oct14.025522.4259@math.lsa.umich.edu>
Date: 14 Oct 90 02:55:22 GMT
References: <1320@carol.fwi.uva.nl> <1990Oct13.120111.21252@math.lsa.umich.edu> <1370@carol.fwi.uva.nl>
Sender: usenet@math.lsa.umich.edu
Organization: University of Michigan Math Dept., Ann Arbor
Lines: 33

In article <1370@carol.fwi.uva.nl> croes@fwi.uva.nl (Felix A. Croes) writes:
>>Just as a point of reference, the standard format is a 720K disk of 80 tracks
>>and 9 sectors per track. I routinely use 10 sectors per track and 82 tracks.
>>That's standard for me, but not so standard that I'm going to hardcode those
>>numbers into the device driver. The hardware is flexible, why shouldn't the
>>software be as well?

>  You mean I cannot use my 800K tar file disks with the new patches because they
>are so *flexible* (the patches, not the disks)?

>  As for standards, there may be a lot of them but a single user typically uses
>only one. I use 10 sectors per track and 80 tracks (my poor old disk drive just
>cannot handle any more). This is probably the minimum for all disk drive types.

>  I am not really against this "flexible" drive type, even though I will never
>use it. But to be able to access the whole of a disk, I need multiple devices.

Or how about a standard method of telling the device driver (ioctl) the current
disk geometry? This is what's been holding up the formatting routine for the
Minix device driver. The device driver currently has the byte length of a track
hard coded, so one cannot format other than 720K diskettes with Minix. All we
really need is a couple ioctls to say track size and sector layout (sector
sizes, # per track, gap lengths, etc.) then everything will be hunky-dory.

As for using 800K tar files, well, you can also use dd to skip the first block
of the disk when reading and writing the tar file. You're only giving up 512
bytes, is that so much to ask? (Naturally the tar file must have first been
written this way for it to work...)
--
  -- Howard Chu @ University of Michigan
  one million data bits stored on a chip, one million bits per chip
	if one of those data bits happens to flip,
		one million data bits stored on the chip...