Date   : Sun, 22 Dec 1985 08:34:55 GMT
From   : "Richard L. Klappal" <rlk%chinet.uucp@BRL.ARPA>
Subject: Re: disk errors [!PLEH]

In article <633@sfmin.UUCP> jeffj@sfmin.UUCP (J.S.Jonas) writes:
>[BDOS err on a: bad sector]
>
>   I see that message way too often.  I am using NASHUA diskettes
>purchased bulk from JDR, so the medium should be fine.
>They start off error free, but then disaster strikes.
>(well, I'm using ED until I get WS.  Could ED be bombing the disk?)
>I think the sector CRC may be off.  Is there a program for CP/M
>similar to FSDB that allows you to read a bad sector, edit it and
>write it back with a new CRC?

It sounds like you may have a problem with dirty heads and/or head
alignment.  The higher numbered tracks are towards the hub, thus
the information is packed more tightly there.

Re: disk editors, check most any RCP/M for Ward Christensen's DU
program (or its later derivatives).  It will allow you to read/edit
/rewrite any sector on the disk, and I have used it on Os1, Kaypro, and
the pseudo-disks that the Mimix package creates for CP/M on my Fortune
32:16 (UN*X derivative), all without any modification whatsoever.
There are commercial editing programs avail (Disk Doctor, Inspect, and
who knows what else), that may be easier to use than Wards, but they
aren't any better (my opinion).

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