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From: hall@cod.NOSC.MIL (Robert R. Hall)
Newsgroups: comp.os.minix
Subject: more on dosread problem
Keywords: dosread, disk drives
Message-ID: <1679@cod.NOSC.MIL>
Date: 26 Oct 89 15:17:22 GMT
Organization: Naval Ocean Systems Center, San Diego
Lines: 18


For a MFM disk drive which has 17 sectors/track, If I assign 
/dev/dosC with major = 3, minor = 0, I find dosread.c begins reading
with disk sector 0.  But the DOS boot sector was found at sector 17.
If I change /dev/dosC to minor = 1, then dosread.c starts with disk
sector 18 (has been rounded to the next 1k byte boundary) missed by
one sector.

And for a RRL disk drive which has 26 sectors/track, the boot sector
is on sector 26 and with  /dev/dosC assigned with minor = 1, dosread
starts with sector 26 and dosread works just fine.

The conclusion of this is, that for dosread works or not depends
on whether or not you disk drive has an even or odd number of sector
per track.

Robert R. Hall
hall@nosc.mil