[AUUG-Talk]: 1988: Specs and costs of mini-computers

steve jenkin sjenkin at canb.auug.org.au
Sun Nov 20 12:22:58 EST 2011

I was hoping some of you on-list might remember the specs and costs of
mini-computers circa 1988.

A 2009 piece on ACM Queue, "Triple-Parity RAID and Beyond" by Leventhal
sent me back to re-reading the seminal 1988 paper by the UCB group
(Patterson et al):
  "A Case for Redundant Arrays of Inexpensive Disks (RAID)".

It wasn't until I read the '88 paper I put the BSD / CSRG at UCB connection
together... So this group would've had a lot of VAX knowledge.

I've been trying to recalculate the various cost/MB given in the paper.

The RRP's given in the press (Computerworld) and IBM Archives for
3380 disks (7.5Gb, 14" platter, 6.5kW) and their controllers suggest to
me $63/Mb for 'SLED' (Single Large Expensive Disk) rather than the
"$18-10" in the Patterson paper. [Educational pricing?]

I haven't tracked down the RRP's of the Conner CP-3100 (3.5", 100MB
SCSI) drives mentioned in the paper for "$10-7/MB", but have found an
on-line collection of disk prices suggesting the drives would've cost
around $1,000 ea. (Dahlin's collection below)

Have no real idea about SCSI controllers at the time, costs or models.
Back then I worked on a new PDP-11/23 system with dual SCSI disks. I
believe we used Emulex SCSI controllers.
Can't remember price of system or disks. $30-$50,000 probable.

What I'm writing to you about is how, in 1988, a system mentioned at the
end of the paper could've been built and a guess at their cost:
  comparing an IBM 3380 disk
  with 100 * 100Mb CP-3100 disks,
  costing "disks and controller" $11-8/MB.

I think there are 3 reasonable configurations to consider:
 - small scale. eg. PDP-11 with 2-4 SCSI controllers and some uplink.
 - high-end device: VAX with 16 SCSI controllers + IBM channel(s).
 - high-end system: VAX with 16 SCSI controllers, part of a VAX cluster.

In their follow-up paper in 1994, Chen et al, "RAID: High-Performance,
Reliable Secondary Storage" use two widely sold commercial system as
case studies:
  NCR 6298 and
 StorageTek's Iceberg 9200 Disk Array.

The (low-end) NCR device was more what we'd call a 'hardware RAID
controller' now, ranging from 5 to 25 disks. Pricing $22-102,000.
It provided a SCSI interface and didn't buffer.

The StorageTek's Iceberg was high-end.
Starting at 100GB (32 drives) for $1.3M, up to 400Gb for $3.6M.
Not sure the interface, probably multiple IBM 'channels' (ESCON by then?)

I've been able to find technical data on VAX systems:
HP's page for VAX 6000/300 tantalisingly says:

'VAXcluster I/O Servers:	Up to 15'
'Max I/O Throughput:	60 MB/s'

Whilst NetBSD provides a very rich catalogue of the VAX series, it's too
much volume for me, cryptic and without pricing.


Through this I have learnt that the original SCSI bus was 8-bits wide,
single-ended and did 5MB/sec (uni-directionally?).
The UNIBUS, the original PDP-11 backplace, did 5MB/sec, whilst the
cheaper Q-BUS did 3.3MB/sec.
There was also SBI, VAXBI, XMI and CI (Cluster Interconnect), with
speeds of 13.3MB/sec to the "60MB/sec" above:  maybe for 6*VAXBI.

If you can point me at any resources or recount any of your
memories/experiences at the time, especially with rough pricing and
configs for my 3 'reasonable configs', I'd much appreciate it.

If you actually built a somewhat comparable system at the time, VAX or
not, that'd be even better :-)

I already have one recollection from the time:
 At Sydney Uni, they paid $30k for a 1MB RAM upgrade for a VAX (11/780?)

steve jenkin


IBM Archives: '20th Century disk storage chronology'

Dahlin's Disk price data: RRP's of HDD's

Steve Jenkin, Info Tech, Systems and Design Specialist.
0412 786 915 (+61 412 786 915)
PO Box 48, Kippax ACT 2615, AUSTRALIA

sjenkin at canb.auug.org.au http://members.tip.net.au/~sjenkin

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