Wren VII format problem

[Larry Beaulieu]

I am trying to migrate a Wren VII from a DECstation 3100 (where it worked
successfully) over to my 3/80 running SunOS 4.0.3 without success.

When running format I can get the original defect list off the drive and
can commit it without failure.  Attempting to extract the defect list does
fail.  When attempting to format the drive after committing the defect
list I get the following:

FORMAT MENU:
        disk       - select a disk
        type       - select (define) a disk type
        partition  - select (define) a partition table
        current    - describe the current disk
        format     - format and analyze the disk
        repair     - repair a defective sector
        show       - translate a disk address
        label      - write label to the disk
        analyze    - surface analysis
        defect     - defect list management
        backup     - search for backup labels
        quit

format> format
Ready to format. Formatting cannot be interrupted
and takes 33 minutes (estimated). Continue? y
Beginning format. The current time is Wed Mar 27 12:41:14 1991

Block 3  (0/0/3), Fatal non-media error (no sense info)
failed
format>

It takes about 20 minutes after beginning the format for the error message
to appear.  This failure also causes the following to be displayed on the
console at the same time:

bluefish> sd0:  sdtimer: I/O request timeout
        Snap shot(HEX): state= 0, err= 0, stat= 0, int= 20, substate= a0
        ESP xcnt_lo= 0, hi= 0, cmd= 44, cur_target= 1
        flag= 0, stat= 10, step= c4, int= 0

        num_dis_target= 1  scsi_stat= 0  scsi_msg= 0
        DVMA_stat= 10, addr= fff08000
        target= 1, lun= 0    DMA addr= fff08000  count= 0 (0)
        cdb=    a  1  f5  a6  10  0
sd0c:  format failed, no retries, blk 3 (rel. blk 3)
       sense key(0x0): no sense
        Snap shot(HEX): state= 0, err= d, stat= 7, int= c, substate= 41
        ESP xcnt_lo= 0, hi= 0, cmd= 12, cur_target= 1
        flag= 0, stat= 13, step= cc, int= 10

        num_dis_target= 1  scsi_stat= 0  scsi_msg= 81
        DVMA_stat= 0, addr= fff02400
        target= 1, lun= 0    DMA addr= fff02400  count= 0 (0)
        cdb=    a  2  84  ae  2  0


	The partition table used is as follows:

	partition	starting cyl	blocks
	a		0		31500	
	b		30		63000
	c		0		2021250
	d		90		246750
	e		0		0
	f		325		1230600
	g		1497		449400
	h		0		0

	(which works out to 15 * 70 = 1050 blocks/cylinder)
	and the format.dat entry used is:

disk_type = "CDC Wren VII 94601-12G" \
        : ctlr = MD21 : fmt_time = 4 \
        : ncyl = 1925 : acyl = 2 : pcyl = 1927 : nhead = 15 : nsect = 70 \
        : rpm = 3600 : bpt = 31500

although the identical error occurs if the parameters are entered manually
in the format utility after removing this entry from format.dat.

	What`s wrong with this picture?

Larry Beaulieu		The usual disclaimers apply.
GCA Corporation 
Andover, MA		Getting a bus error is a great way to ruin your day.
beaulieu at gca.com