Date   : Fri, 03 Sep 1982 02:38:00-EDT
From   : Jonathan W Platt <JWP@Mit-Mc>
Subject: Disk Formats

       I am involved in a project which hopefully will provide our
computers with the ability to read or write in any disk format.
We have a great need to transfer customer's data from one micro's
diskettes to another's - given any two micro's.
       The BIOS level coding for this is fairly trivial.  On the
lower levels of drive controller coding however, it doesn't appear
so easy.  One must know if the particular micro is using the IBM
3740 single density format, IBM system 34 double density format or
some off-the-wall format of their own.
       Our computerbasically has two drives.  One of which would
be set to one system's format and the other drive to the destination
format.
       The question is, Who uses what controller's in their micros?,
What density(ies)?, What format?, Hard or soft sectored? and how do
they structure the upper levels of their disks (i.e. # tracks, sectors
per track, block sizes, directory sizes, etc...).
       Mainly though, I'm interested in how the disk are formatted
(address fields, data patterns - things never seen by the typical
user).
       Does anyone out there know of a compilation of this type
of information?  Individual input from those who have found this
information through hacking their micros is also very, very welcome!
       Please reply to me directly.  If there is a demand for it, I
will compile the data and make it available on the net.


                       JWP@MIT-MC