Subject: RE: partitioning RD54
To: None <>
From: Douglas Meade <>
List: port-vax
Date: 02/27/2000 22:49:36

Do you think that the same caveat applies to the RD53?  I have about
six of these that all had VMS working on them when I got them.  I
disklabel'ed and newfs'ed several of them in uVaxIIs, and had them 
working for awhile.  However, I was occasionally getting errors 
similar to the one below, and now they've stopped working.  I 
have tried putting them into a VS2000 and doing the "test 72",
but that computer replies with an error when trying to access
the RD53.  Could these drives be fried now, or is there some other
way to low level format them again, besides in the VS2000?  


> Because the folks who constructed the disktab entry didn't know what
> what they were doing.
> >  The end of partition f looks
> >like it would be at sector 311628, somewhat lower than the 312120 sectors
> >the drive should have or the 312375 sectors given in the geometry section.
> >How many sectors does the RQDX3 actually make available on an RD54?
> Gack!!!  I ranted and raved about this here 3 or 4 years ago, and they *still*
> haven't fixed this brain-damaged disktab entry?  Well, time to rant and
> rave again:
> A RD54 on a RQDX3 has 311300 "normal" blocks.  Those "other" sectors are
> reserved for the RCT and for replacement blocks.  The numbers calculated
> from the drive's physical geometry are meaningless.  They have been
> meaningless since the first UDA50 rolled off the assembly line almost
> a quarter-century ago, giving us freedom from having to know the physical
> geometry of a drive.  
> Well, that rant and rave probably had as much effect (ZERO) as the last
> time I did it, but don't say I didn't warn you.  In particular, on many
> MSCP disk controllers if you issue writes past the end of the "user
> area" of the disk you'll clobber the RCT.  If you do that, well, you're
> almost totally screwed.  If you've got XXDP+ on a PDP-11 you can use
> ZRQC?? to go in and salvage the RCT in some circumstances, but on a
> MicroVAX you're screwed because the field service diagnostics can't
> salvage the RCT.  Heck, the field-service diagnostics are barely capable
> of formatting an already good RD54 into a RD54.
> As to why you get a write error trying to newfs your RD54, I don't think
> the brain-damaged partition table is the reason here, as you almost certainly
> aren't running up against the end of the disk.
> Tim.