Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!hp4nl!targon!gert
From: gert@targon.UUCP (Gert Kanis)
Newsgroups: comp.os.minix
Subject: Re: Amiga Minix Questions (Floppy drives)
Summary: Different format on PC <-> 68K
Keywords: floppy 68000 compatibility
Message-ID: <1453@targon.UUCP>
Date: 18 Sep 90 16:31:58 GMT
References: <1990Sep17.115240.16619@warwick.ac.uk> <7583@star.cs.vu.nl>
Reply-To: gert@targon.UUCP (Gert Kanis)
Followup-To: comp.os.minix
Organization: Nixdorf Computer BV.,SWP, P.O. Box 29,Vianen, The Netherlands
Lines: 37

In article <7583@star.cs.vu.nl> raymond@cs.vu.nl (Raymond Michiels) writes:
>phupp@warwick.ac.uk (S Millington) writes:
>> 2) In the announcement posting it was stated that the Amiga version would
>>    work either on one or two 720K drives.
>>                              ^^^^
>>               The Amiga uses 880K drives, or has this now been sacrificed for
>>    compatibility with PC drives, and mac drives? Or was this, hopefully, a
>>    typo.
>
>This was not a typo. We have sacrificed 160K to be compatible with
>PCs, Atari's and Macs.
>
>	-Raymond.

Just to prevent the introduction of wild rumours and misunderstandings :-)

Disks are and are not the same between the PC's and the 68000's .
They are essentially the same physical format  i.e. 80 tracks of 9 sectors.
But unfortunely the way things are written is different  i.e. byte ordering.

This has grown as it is somewhere in history (when Minix ST was developed).
As someone pointed out in this newsgroup about a year ago  when we talk
about how Minix writes on disk  we speak of File Systems.  There's no law
that you should be able to read them across architectural boundaries.
(Allthough it can be quite handy at times :-/ )

During the porting of Minix to the Amiga and the Mac care was taken to
not to create yet another variant. So at the moment we live with PC disks
and M68000 disks  so to speak.   (Does the Sparc have floppies ?).


P.S.  Don't send me mail telling that PC's support other disk formats as
      the one mentioned. The story however stays the same.
--
Gert Kanis      gert@targon.UUCP

Just to introduce wild rumours and some misunderstandings :-)