Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!csd4.milw.wisc.edu!lll-winken!uunet!ibmpa!conrad
From: conrad@ibmpa.UUCP (Conrad Minshall)
Newsgroups: comp.sys.ibm.pc.rt
Subject: Re: ESDI disks for RT (AOS 4.3)
Message-ID: <1269@ibmpa.UUCP>
Date: 10 Jun 89 01:25:52 GMT
References: <3396@ursa-major.SPDCC.COM>
Reply-To: conrad@ibmpa.UUCP (Conrad Minshall)
Organization: IBM AWD, Palo Alto
Lines: 20

In article <3396@ursa-major.SPDCC.COM> dyer@ursa-major.SPDCC.COM (Steve Dyer) writes:
>It gave a write error on each track (sector=1 SCT=34),
>and one which didn't disappear with repeated formats, and the drive gave
>errors trying to run newfs under AOS 4.3.

I wrote the EESDI hd driver and format code for AOS 4.3.  That was long ago,
and by now I've forgotten 99% of how it works.  W/o digging into the code,
here's my idea of what the source of your trouble is:

The EESDI disks for the RT, as shipped by IBM, have a "hidden defect table" at
the 18th sector on the 2nd track of the 1st cylinder.  See disk(4) man page.
I suspect your troubles result from the fact that your disks do not have such
a table on them.  Format(8) uses the presence or absence of such a table to
decide whether there is a hidden sector at the end of each track.  Ie format
adjusts its idea of the number of sectors per track if the table is present.

PS: I'll be at USENIX next week.

Conrad Minshall uunet!ibmsupt!conrad (415)8554454 conrad@ibmpa.tcspa.ibm.com
         None of the above represents IBM's Official Policy, etc.