navoceano@oacis.span.nasa.gov (03/01/90)
Still flush with the success of interfacing a surplus Fujitsu M2284K SMD
disk to one of our Sun 3/280's, I decided to go out in search of really
big game. In our warehouse (shades of Indiana Jones) I located a raft of
surplus Magnetic Peripherals Inc. (aka Segate) mod BZ9A7A 160 Mbyte SMD
disks. These were rebranded Data General mod 6160 and had come from a
recently cancelled project.
The BZ9A7A is roughly similar to the Fujitsu M2284K in size and design.
The folks at Segate told me that it is electrically similar to a CDC 9766
( Magnetic Peripherals "spun off" from CDC). The disk has 4 14" platters.
Only 6 surfaces are used. The topmost and bottommost surfaces are unused.
There are 5 data surfaces and 1 servo surface; 11 heads total (10 data, 1
servo); 823 cylinders with 20,160 bytes per track.
We have the Data General 6160 O&M manual. This is rather specific to use
with Data General computers. I also found a CDC 9766 manual which has some
useful information; particularly about sector addressing.
There is no similar disk in the current format.dat file. I guessed at 32
sectors of 630 bytes per track and made up the following format.dat:
disk_type = "Magnetic Peripherals BZ9A7A" \
: ctlr = XY450 : fmt_time = 4 \
: ncyl = 821 : acyl = 2 : pcyl = 823 : nhead = 10 : nsect = 32 \
: rpm = 3600 : bpt = 20160 : bps = 630 : drive_type = 2
When I run format:
1. The disk "clatters" and format reports an unknown disk on xy0.
2. I identify it as a BZ9A7A.
3. Format tries to read the defect info.
4. Format reports a "lost interrupt" trk0, blk0.
5. All attempts to read, write or format the disk produce the same
"lost interrupt" response.
6. The disk status lights sometimes report a "no seek command det."
This is a status report, not a fault.
If there are any SMD gurus out there, I need to figure out:
1. Is this just a waste of everyone's time?
2. Is the disk functioning properly?
3. Is the format.dat correct?
I would particularly like to find a good, general discussion of format and
format.dat and getting generic SMD disks to work on a Sun.
Thanks
Donald R. Newcomb
Naval Oceanographic Office
Stennis Space Center, MS 39522
(610) 688-5998
Autovon 485-5998
navoceano@oacis.span.nasa.gov
navoceano%oacis.dnet@turner-joy.noarl.navy.mil