Path: utzoo!utgpu!water!watmath!clyde!rutgers!mit-eddie!husc6!cmcl2!nrl-cmf!ames!pasteur!ucbvax!sdcsvax!ucsdhub!esosun!seismo!uunet!mcvax!botter!ast
From: ast@cs.vu.nl (Andy Tanenbaum)
Newsgroups: comp.os.minix
Subject: Re: fsck fix to check the hard-disk
Keywords: MINIX
Message-ID: <1834@botter.cs.vu.nl>
Date: 22 Jan 88 16:52:05 GMT
References: <1179@ark.cs.vu.nl>
Reply-To: ast@cs.vu.nl (Andy Tanenbaum)
Organization: VU Informatica, Amsterdam
Lines: 23

In article <1179@ark.cs.vu.nl> smagt@cs.vu.nl (Smagt v der PPP) writes:
 >   Fsck seemed not to be able to check my (XT-) hard-disk, so
 >I tried to find out what was wrong and found that the number
 >of sectors per cylinders seemed to be assigned wrongly (as 
 >opposed to version 1.0 MINIX.) Here's what I've done:
 >
 >diff old_fsck.c new_fsck.c:
 >1867c1867
 ><			cylsiz = 85;	/* sectors per cylinder */
 >---
 >>			cylsiz = 68;	/* sectors per cylinder */
 >

I checked the "official" current version, and sure enough it is 85.  I
suspect I know what happened.  I must have gotten this version from
someone (I forget who) who did something useful to it (I forget what) for
no doubt a good reason (I forget why).  This person undoubtedly had a
drive with 5 heads.  Since there are 17 sectors per track (circles are
round and pi is not a power of 2), he logically set cylsiz to 5 * 17 = 85.
For us ordinary four-headed monsters, 68 is indeed a better value.  Thanks
for the fix.

Andy Tanenbaum (ast@cs.vu.nl)