Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!tektronix!psueea!psueea.uucp!kirkenda
From: kirkenda@psueea.uucp (Steve Kirkendall)
Newsgroups: comp.sys.atari.st
Subject: Re: Question on 1.44 meg drives...
Message-ID: <1417@psueea.UUCP>
Date: 28 Jun 89 01:01:41 GMT
References: <8906261817.AA17231@jade.berkeley.edu>
Sender: news@psueea.UUCP
Reply-To: kirkenda@jove.cs.pdx.edu (Steve Kirkendall)
Organization: Dept. of Computer Science, Portland State University; Portland OR
Lines: 33

In article <8906261817.AA17231@jade.berkeley.edu> WSCART01@ULKYVX.BITNET writes:
>
> I suppose most of you are aware of 1.44 Meg drives out for the IBM. They
>use 160 tracks instead of the 80 tracks normal drives. The question i'm
>pondering is: Why has no one hooked one up to an ST? I suppose there is
>either a harware or software diffuculty to overcome. Does anyone know
>which, and exactly what the problem is?

Actually, the 1.44M drives are 80-track double-sided drives, just like 720K
drives.  The difference is that they store 18 sectors per track instead of 9.
To do this, they have to read/write data at a higher data rate.  The disk
controller built into STs can't operate at the higher data rate, so the first
thing you would have to do is find a version of the controller chip that
can handle the higher data rate.

The next thing you would have to do is write a new device driver that exploits
the higher data rate of the new controller.

Finally, to do it right you would have to add a new line to the cable that
goes out to the floppy, to allow the ST to detect the "high density" mark
on the diskette.  (3.5" 1.44M diskettes have an extra hole, simililar to
the write-protect hole, to indicate that they can be formatted at 1.44M).

You want detailed descriptions with part numbers, pin numbers, and source code?
Sorry.  I don't have that information.

BTW, about 80% of the PCs out there can't use 1.44M drives, even if they have
the right hardware, because the PC's BIOS only supports about half a dozen
different formats and, for older PCs, nobody thought to add that precise
configuration.  This is changing, sure, but don't expect 1.44M to be the
next industry standard.
	-- Steve Kirkendall
	   ...uunet!tektronix!psu-cs!kirkenda