DEC SDI drives (was Re: What is this? Looks like maybe a VAX of some sort..)

From: Gunther Schadow <gunther_at_aurora.regenstrief.org>
Date: Sat Jun 1 15:45:13 2002

Ethan Dicks wrote:

> --- Innfogra_at_aol.com wrote:
>

>>I think the first picture is a MicroVAX system with the RA Disk drive on
>>the top. I think it is the one listed at $154,000+ and called disk memory
>>unit.
>>
>
> A single DEC RA81 was $26,000, MSRP, in mid-1984. At this point, you'd
> have to be pretty hard up for an SDI disk to want to pay real money
> for one. I have a couple. I don't use them unless I _really_ have to.
> They have a 30A momentary surge at spinup, and draw many amps (spec'ed
> at 8A) when running. From a megabytes/megawatts standpoint, they are
> at the bottom of the SDI curve.


Right, I have one RA81 and one RA82 and that's all I can/want to fit.
I do like SDI disks though. RA90s are my standard disks for my VAX
6000s and they are fun. The nice thing about RA82s is that you can
show them to people and say that they have almost the same capacity
as a CD ROM drive (and they have the same shape, only scaled by a
factor of, let's say, 8 to 10. Then you can open the hood just like
in my car, check the alternator belt and I just haven't found the
oil dip stick yet :-).

I do want to get an RA60 some time, but as you say, it's a big deal
with buying and shipping. I actually know where a few are rotting in
the mud, but it's always the problem buying stuff from a scrap yard,
you can end up paying more than in a happy hour on eBay for something
that may be in much worse shape (rotten in the mud.) The weird thing
about it is, the raw scrap value may not be that high, and those places
tend to never actually capitalize on the scrap value. They let the
stuff sit in the yard for decades. That's good on the one hand, so it
stays somewhat conserved for the real desperate to pick up and pay for
anyway. I guess the number one resourde you need as a scrapper is
real estate and a second source of income, so you don't need much
cash flow.

BTW: I have a bunch of RA60 platters that wait for their mother ship
to come some time in the future. Now, I never tried those platters.
But on visual inspection I do see one concentric scratch of about
10 degrees length on each platter. That is the mark of a head crash,
right? Does that mean that these platters are drop dead, never to
be used again? Or is it just a few sectors that are killed that way?
Is the slight roughness of the surface there going to damage the
r/w heads on a working drive? If so, is there a way to polish this
spot to make the rest of the platters useable?

cheers,
-Gunther



-- 
Gunther Schadow, M.D., Ph.D.                    gschadow_at_regenstrief.org
Medical Information Scientist      Regenstrief Institute for Health Care
Adjunct Assistant Professor        Indiana University School of Medicine
tel:1(317)630-7960                         http://aurora.regenstrief.org
Received on Sat Jun 01 2002 - 15:45:13 BST

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