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From: crp@stcvax.UUCP (Charlie Price)
Newsgroups: net.micro
Subject: Re: 500Mbyte ROMS and more... - (nf)
Message-ID: <274@stcvax.UUCP>
Date: Mon, 28-May-84 14:53:16 EDT
Article-I.D.: stcvax.274
Posted: Mon May 28 14:53:16 1984
Date-Received: Fri, 1-Jun-84 00:04:48 EDT
References: umn-cs.462, <411@bunker.UUCP>
Organization: Storage Technology Corp.  Louisville, CO
Lines: 73

>       What you do is put 400M of whatever on your 500M CD and leave the
>  rest blank.  You have cunningly built write capability into the drive,
>  and when a bug comes up, you've got 100M of space to fix it in.

A nice idea, but I'm not sure you can do it.

Another division of Storage Technology is building a 4 Gigabyte
write-once-read-many optical disk.  You record information by burning
spots onto a disk-shaped media and you read it back by looking at the spots.
It isn't possible to mass-produce this disk with pre-recorded
information on it -- you would have to write each disk.
This is quite different from a video disk (analog) or CD where the disks
can be reproduced by a mastering process quite cheaply
(on the order of $10 for reasonable volumes).
The whole point of using a video disk or CD is that it is cheap to
reproduce once you have done the master.
I don't think that you COULD record anything with a laser on a
video disk or CD once it had been reproduced; it simply isn't that sort
of media.  A video disk reader for a computer is really just a
heavy duty Analog to Digital device with a *LOT* of error correction.
CDs are a better story in that regard I think, but still don't have
good enough error characteristics for storing correct digital data.

Reference Technology, a small startup in Boulder, is building a
video disk reader that works like a disk drive (i.e. a fairly fast
servo positioner, a "block" structure on the device, and a heavy-duty
ECC scheme).  The video disk is just a standard old video disk and
you could play it on a TV though the result might be disappointing
(a Michael Jackson video will go into their reader with equally
disappointing results when considered as a data-storage disk).
They expect to have at or just under a gigabyte on a video disk.
They are just at the point of first customer ship of an evaluation unit.

The interface is something standard (SCSI?) and it should be able to
hook up to both larger systems (like VAXen) and PCs that have an
interface of that sort.  They are definitely planning that it should
be usable with a PC, but it is sufficiently expensive that it isn't
a hobbyist sort of device (I either don't know or can't tell you a price).

Their market isn't what people have talked about in this group --
it is much more the static database market -- and there is a larger
one than I ever thought there was.
For instance, somewhere in the US there is a legal database that
contains something like every brief ever submitted to a federal court.
Lawyers query this by significant words and phrases.
Generating the index information for all significant words and
phrases takes WEEKS of large mainframe time, but then the retrieval
is fairly fast.
There is a large mainframe whose sole purpose is to retrieve items
from this database in response to textual queries.
This service is apparently fairly expensive and for various reasons
of equipment or convenience not all lawyers are able to use it.
They want to blast the database onto video disk(s) and ship the
database to lawyers (or firms more likely) who have a PC or
a larger machine.  Retrieval from the fully indexed database is
something that even a PC or a small UNIX machine can do quickly enough.

I couldn't speculate on any future plans they have for CDs other
than to note that people in the company think they are interesting.

Incidentally, the ECC required for their reader is very heavy-duty.
The error rate they have to expect is 1 bit in 100.
They have an ECC that should allow correction of a 1 inch error burst
on the disk.  If the physical damage didn't matter, you could take a
video disk, shoot a hole in it with a 45, and their reader could still
read it without error.

-- 
Charlie Price  -  STC (disk division)
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