jeffj@sfmin.UUCP (J.S.Jonas) (12/18/85)
[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?
Should be fine is the correct phrase. I added a DSDD drive,
and several diskettes have failed verification. It is always
tracks >32 on side 1 (as opposed to side 0 which is used by SSDD drives).
I doubt it is the disk drive since it is only in the inner tracks
on one side (seek errors would be both sides, a bad head would be
all tracks. Maybe the wire to the head?).
Cable problems would be intermittent.
I doubt it is the driver since it is side dependent.
Could it be the medium? If anything I'd suspect the 0 side since
the bottom side seems to have a larger unpolished hub than side 1
(the upper side). Any ideas?
Thanks in advance.
Jeff 'this is frustrating' Skot
{ihnp4 | allegra | mcnc} attunix ! jeffjrlk@chinet.UUCP (Richard L. Klappal) (12/22/85)
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). -- --- UUCP: ..!ihnp4!chinet!uklpl!rlk || MCIMail: rklappal || Compuserve: 74106,1021 ---
aep@abic.UUCP (Alex Pensky) (12/23/85)
> [BDOS err on a: bad sector] > I see that message way too often. ... Could be that CP/M is still using the directory and disk parameters from a disk previously in the same drive, for which the current disk access would have been erroneous. The solution is to warm boot (control C) after every disk change. If you are running purchased software which requires disk changes but doesn't reread the directory after you do so, the software is buggy. Sorry if this seems like trivial help, but you didn't say what causes you had already ruled out before suspecting your diskettes. - Alex Pensky