🚀 go-pugleaf

To: mark@osupyr.UUCP 
Subject: Re: RD54 disktab entry needed!

> 
> We are running 4.3BSD on three MicroVAX IIs, for which
> we have recently acquired a set of Maxtor 380Mb ESDI disks.. 
> These disks supposedly, for all intents and purposes, partition just
> like RD54 disks ... however, we lack the disktab information necessary
> to partition it (and since the disks use a UDA-50 controller/driver,
> diskpart does us no good.) If anyone has a disktab entry for an RD54,
> please oh please send me a copy.

Just because it's got a controller emulating MSCP doesn't mean you want
the disktab for an RD54. Since MSCP hides the disk layout almost completely,
it would in fact work anyway, but probably at a cost of inefficiencies in
disk access/trasfer rate.

What you want is to take the Maxtor's number of heads, #cylinders, and
#sectors/track and work out a partition table.  Now, the partition
lengths in the table below are easily changed on an Ultrix system,
using the chpt(8) utility. I think you may be stuck there on the 4.3
system, but for completeness I'll finish describing this. In any case, 
the mkfs should get the correct disk info to lay out the file systems.

As I was saying, here's one we use for our Emulex QD21/Maxtor 4380
combination (also the same on a Webster controller, by the way):

# Added 9/17/86 WFW + JT for Emulex QD21 + Maxtor 4380 disk subsystem
# This is an RA emulator about 309 Mbyte formatted
qd380|QD380|Emulex QD21 + Maxtor 4380 disk:\
        :ty=winchster:ns#33:nt#15:nc#1218:\
        :pa#16335:ba#4096:fa#1024:\
        :pb#33165:\
        :pc#602745:\
        :pd#82170:bd#8192:fd#1024:\
        :pe#471075:be#4096:fe#512:\
        :pf#82170:bf#4096:ff#1024:\
        :pg#471075:bg#8192:fg#2048:\
        :ph#553245:bh#8192:fh#2048:

Only the a, b, c, and h partitions seem to be useful.  Notice that
there are 34 sectors, but one is held back for on-track forwarding.
There are also really 1224 or 1225 cylinders, but again some are kept
for bad blocks. 

***Ultrix info only!***
Most of these controllers tell the Ultrix RA driver that the disk is an
RA81. This means that the first time you call newfs(8) after formatting the
disk, it will write an RA81 partition table onto a reserved area in the
`a' partition. What you do then is use chpt(8) to alter the partition
sizes to conform to the above. You then redo newfs(8) for the `a' partition
and then whatever others you're using. Note that you can't decrease the 
size of the `a' partition below 15884 sectors. I'm not quite sure why.
-- 

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