yedidya@bimacs.BITNET (Yedidya Israel) (10/19/88)
We want to re-format one of our rd53 disks. We are doing it with the
formatter of the IBM PC. Rd53 is Micropolis-1325 equivalent. We are
asked to enter parameters that we do not know, can you help us with
it?
The parameters are:
#cyls: my disktab says 963 but are there any more for bad blocks?
#heads: 8 that we know already
starting reduced write cylinder
write precomp cylinder
maximum correctible error burst length
CCB option byte
Israel.vixie@decwrl.dec.com (Paul Vixie) (10/23/88)
(Yedidya Israel) writes:
#
# We want to re-format one of our rd53 disks. We are doing it with the
# formatter of the IBM PC. Rd53 is Micropolis-1325 equivalent.
If you plan to use the drive on a RQDX3 controller, you will probably have
to format using that controller. Generally, ST506 drives are formatted
differently by each controller that can use them. The RD53 is not just
1325 compatible; it _is_ a 1325 in sheep's clothing.
# #cyls: my disktab says 963 but are there any more for bad blocks?
963? My /etc/disktab says:
rd53|RD53|DEC RD53 Winchester:\
:ty=winchester:ns#17:nt#8:nc#1024:\
:pc#138672:bc#8192:fc#1024:\
17 * 8 = 136 sectors per cylinder; 136 * 1024 = 139264, which is higher than
the size of the C partition. Hmmm. 139264 - 138672 = 592, which is probably
where Ultrix and/or VMS and/or the RQDX3 keeps the bad sectors. I don't know
if Ultrix still uses the 4BSD "bad144" scheme or not.
Anyway, 963 is wrong. This drive has 1024 cylinders; check your local Sun
machine (some of which use 1325 drives via a SCSI->ST506 adaptor) if you don't
believe me.
# #heads: 8 that we know already
8 heads, yup. Probably five platters, giving 10 surfaces, one of which is a
servo track and one of which I guess is not used. Strange.
# starting reduced write cylinder
None. 0 or 1024, whichever turns off this unneeded feature.
# write precomp cylinder
None, again: 0 or 1024, whichever turns it off. Write precomp and reduced
write current were needed on crufty old drives, but the 1325 is beyond all
that as far as I know.
# maximum correctible error burst length
# CCB option byte
Sorry, you've got me. The last DOS formatter I used was "hardprep", which
did not ask for this info; the DEC RQDX3/RD53 formatter doesn't ask any
questions at all.
Again, though: if you want to use this drive on a DEC RQDX3 controller, you
will probably have to format it on that controller as well. The DEC diag
tape that comes with microvax systems will have a formatter on it; you just
have to wait 30 minutes or so for the TK50 to read it in.
Good luck.
#
# Israel.
(not speaking for the company...)
--
Paul Vixie
Work: vixie@decwrl.dec.com decwrl!vixie +1 415 853 6600
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