From: edwards@ee.fit.edu (John Edwards)
Newsgroups: comp.periphs.scsi
Subject: keywords:RODIME,root dir,glitch,ARGH,help?,hacks?
Summary: discussion of options to fix a glitched rodime SCSI drive
Keywords: rodime,in2000,msdos,root,recover
Date: 31 Dec 92 02:47:33 GMT
Organization: Florida Tech, CP/EE Dept.


Posted for a friend, email replies to luckey@rtfm.mlb.fl.us

Well, I have seen other hard drives do odd things when sitting idle.
seagates burble (updating system info data on usage?)  Minscribes
whose LEDs turn read when heads park on idle timeout.  So, how was I
to know that that "clickBurble" my new Rodime 8259T (yes, another
Hi-tech customer) wasn't doing what it was supposed to.  Turns out
what it WAS doing was deciding that I'd turned off powerand suddenly
changed my mind: its power off circuit thought it was time to park
heads.

Well, it was wrong.  And one time it screwed up the 2nd sector of
my DOS root directory.  But more on that later.  After researching
what a rodime was supposed to do, I decided that my AT's power
supply had more ripple than the rodime wanted.  So I made up a
special power cable with 2200 mfd caps on both 12V and 5V lines.
This seems to work.  no more clickBurbles.

so now I have a drive with a screwed up directory, what to do
: try Norton Disk Doctor.  NDD says no luck, use Norton Calibrate
to reformat sector.  Calibrate says no way.  Oh well, It knows no
kind of reformat track for a SCSI drive.  Suggested solution: reformat
everything.

Well, I'm not quite ready to do that.  While I have my important stuff
backed up, there is alot of collected non critical data I'd prefer not
to lose if I can avoid it.  If I could get that 2nd sector to be
writable again, I feel NDD could repair the volume.  But how to do
that when a SCSI FORMAT UNIT command is an all or none type of thing.

Well, these are the only things I can think of being able to do

1) back up a sector by sector image of the drive, reformat, then do
   a sector by sector restore.

2) intercept the proper intercept and make reads and writes to that
   sector, and that sector only, work from a RAM copy.  Then correct
   with NDD, then do a file by file backup

3) find out if a Rodime 3259T supports a RELOCATE SECTOR scsi command,
   and if it does, somehow issue it one.

None of these seems to be an off the shelf solution.  I don't have
any software that can do a sector by sector backup.  I don't have
a device driver that can ghost to RAM a bad sector.  I don't have
a 3259T manual, nor a IN2000 utility to issue random scsi commands.

So I have 100 Megs of data in the first half of a 200 meg hard drive
with nowhere to put it.  

What I do have is.  an 85 meg ST296 on its way here, a copy of an
ASPI driver for an IN2000 scsi adaptor, and access to source example
via FTP or GEnie.  So how can I put it together?

Best I can think of is writing a sector by sector backup program from
scratch,  calling INT 025 to get raw sectors, then saving it on a 
STACKER compressed ST296.  But I'm leary of debugging a new program
on data that I don't want to lose

Does anyone have any better ideas?

Does anyone know an already implimented version of one of the hacks
I've thought up?

Does anyone know how to do a relocate sector on a RODIME drive?

December has been a bad month for diskdrives for me.
Newsgroups: comp.periphs.scsi