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From: dyer@atari.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: Interesting
Message-ID: <575@atari.UUCP>
Date: Tue, 3-Mar-87 12:17:58 EST
Article-I.D.: atari.575
Posted: Tue Mar  3 12:17:58 1987
Date-Received: Fri, 6-Mar-87 03:56:32 EST
References: <8703020431.AA05950@ucbvax.Berkeley.EDU>
Distribution: world
Organization: Atari Corp., Sunnyvale CA
Lines: 31

> If you have a bad partition, or get a bad partition on your hard disk, try
> writing a little program which does a read RWABS from boot sector zero from a
> partition of the same size and writing it to the boot sector of the bad
> partition.  If this doesn't work, try one more sector, and keep trying one
> more sector, for a few.  Chances are you will be able to recover some of the
> STuff.  I will post a program which will do this, soon (like this week).

Logical sector zero (in a partition) contains a standard floppy-like
prototype-BPB with only the fields BPS, SPC, RES, NDIRS, NSECTS and
SPF valid (see your Guide, "Boot Sectors", pp 58-60 in my edition):

	BPS	= 512
	SPC	= 2
	RES	= 1
	NDIRS	= 256+
	NSECTS	= #sectors in partition
	SPF	= (((NSECTS/2)+2)/256)+1

NDIRS is nondeterministic, but is >=256.  Word values (like SPF) are
stored in 8086 format.  16 bit FATs are always used.


The Rwabs() trick mentioned above should work unless the FATs and root
directories have been clobbered.  I supposed you could back them up to
floppy before you ran that Michtron utility....

-- 
-Landon Dyer, Atari Corp.	    {sun,lll-lcc,imagen}!atari!dyer

The views expressed here do not not
necessarily reflect those of Atari Corp.	Segments are for worms.