VAXen and minimal memory (was Re: The PDP11/04 has landed..)

Guy Dawson guy at
Thu Feb 11 16:38:38 CST 2016

In late '86 I was running a VAX8500 with 2 RA81s and a TU80 for Deluxe
Coachlines in Australia. We computerised their coach reservation system.

System growth was brisk as the company and the application grew. The 8500
became an 8550 and gained some more RA81s and then in late 87 we move to a
new site.

Prior to moving a new 8550, 2 HSC50s, star coupler and 24 (count 'em!)
RA81s in RAID 1 pairs, a spare and a quorum drive and two TU78s
(master/slave I think) were installed at the new site. For the actual
migration we just moved some data on tape.

About a week before the move the live 8550 in the old site failed with a
double CPU fault. I rang the field circus number, logged the fault and
impressed upon them the urgency of the call. After too long with no sign of
an engineer I called again and was told the engineers were on site and
working on the fault. As I could look directly into the computer room from
my desk I knew this was not so. I restarted the live 8550 and called field
circus to vent. They'd got confused between our two sites and two 8550s and
gone to the new site. Turns out that the new 8550 had a double CPU fault
too! We decided to ensure the new 8550 was working and moved with little
fuss a week later. We then moved the old 8550 and completed our VAXcluster.

We later upgraded the HSC50s (took ages to boot off tape) to HDC70s which I
think booted off floppy. Each 8550 ended up with 80MB RAM. It was a pretty
big system. I left Australia in March '88 and visited again a couple of
years later by which time an 8820 had joined the cluster.

Thick Ethernet served the office using LAT terminal servers and two (maybe
four) big terminal servers (PDP11 based think) were connected to Penril
multiplexers for an Australia wide terminal network.

Then there were the laser printers whose power on self test display
included a kangeroo bouncing along the one line LCD display!

Fun times.

On 11 February 2016 at 21:41, Glen Slick <glen.slick at> wrote:

> My memories from the early 1980s are of a room full of undergrads
> working on rows of VT100s (maybe 50+ at least?) on a DECSYSTEM-2065
> running TOPS-20.
> Things usually seemed to run pretty well on that system, until the
> night before programming assignments were due.
> Nothing quite like a room full of VT100s beeping in unison and
> printing the dreaded "%DECSYSTEM-20 not running" message when things
> hit the maximum load, followed by waiting for the system to restart
> and hoping your work in progress was saved recently.

4.4 > 5.4

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