Path: utzoo!attcan!uunet!lll-winken!decwrl!ucbvax!UMIX.CC.UMICH.EDU!krowitz%richter
From: krowitz%richter@UMIX.CC.UMICH.EDU (David Krowitz)
Newsgroups: comp.sys.apollo
Subject: Re:  Can't format SCSI disk, DN2500
Message-ID: <9003231436.AA09751@richter.mit.edu>
Date: 23 Mar 90 14:36:52 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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We have a Sony SMO-503 erasable-optical disk (magneto-optical disk) which
we bought from Workstation Solutions. We found a number of things with the
DN2500's SCSI support:

1) Our original cable was an 8-foot cable made with twisted pair wire
   (round cable). This proved to be unreliable. Workstation Solutions 
   shipped us a 3-foot ribbon cable which has worked well ever since it
   was installed. They are apparently evaluating several other cables
   as this time.

2) Our original boot proms were version 1.8 (pop the lid on the DN2500 and
   look for a socketed chip with a paper tag on it which says something like
   "FRODO 1.xxx" on it -- this is your boot prom chip). We found that even
   though we could format our drive we could not boot from it, and occassionally
   the system seemed to timeout on the drive -- ie. we'd have the drive
   mounted and be accessing some files on it and all of a sudden we'd get a
   "file not found" or "directory not found in pathname" error, and when we
   retried the operation the file was ok. The Sony drive is a fairly slow
   disk (90 msec average access), so we assumed that the timeouts were a
   problem with the drive's speed, but it may be a generic problem with
   external disks. Workstation Solutions advised us that the rev 1.9 boot
   proms would fix the problem of booting from the optical disk and might
   also fix the apparent drive timeouts. Our field service reps obtained
   some new CPU boards for us (apparently the proms are not available as
   a seperate part yet), and both problems have gone away.

3) With either set of boot proms, we found that even though the DN2500's
   self test (invoked by the memonic debugger's TE command) would see the
   disk on the SCSI port, we had to issue the MD command sequence:

   > RE
   > DI SD0:0        (our drive is set to device 0 on controller 0)
   > RE
   > DI N            (we boot diskless from the network, you could give
                      a DI W, DI E, DI F, or DI C to boot from a device
                      other than the external disk)
   > EX DOMAIN_OS

   If we did not issue the DI SD command, the machine would boot, but
   /com/invol, /com/salvol, /com/mtvol, etc. will not recognize the
   disk. With the rev. 1.8 boot proms, we found that we had to run
   invol using option 7 first (to create a bad spot list), and then
   option 1 (to initialize the volume). With the rev 1.9 boot proms,
   we have to use option 7 -f and 1 -f (ie. do not attempt to reformat)
   or we will get a status code 8002a (illegal command for device, or
   something like that) when invol attempts to reformat the drive.



 -- David Krowitz

krowitz@richter.mit.edu   (18.83.0.109)
krowitz%richter.mit.edu@eddie.mit.edu
krowitz%richter.mit.edu@mitvma.bitnet
(in order of decreasing preference)