PDP-9

[Bernie Dwyer]

I watched a film t'other night - "The Dish" - about the role played by
the radio-telescope facility at Parkes, New South Wales, Australia in
the first moon landing. It was mostly a light comedy, but enjoyable.

In the credits was the following:

"PDP-9 supplied by {some company specialising in supplying older
computers/replicas as props}"

My IT career only started in 1984, so I couldn't recognise a PDP-9 if I
tripped over one. Is that the sort of gear that such a facility would
use in 1969? I know that the Parkes radio-telescope was specially
upgraded by NASA for its role.

There was a dramatic moment where the UPS didn't cut over, and "the
computer lost all its settings when the power failed", so the staff
spent 12 hours re-calculating where to point the dish, only to be saved
when the NASA rep pointed at the moon and said something like "there's
your reference point - they've got to be within 3 or 4 degrees".
Harumph!

[h***@kerberos.davies.net.au]

Post by Bernie Dwyer
I watched a film t'other night - "The Dish" - about the role played by
the radio-telescope facility at Parkes, New South Wales, Australia in
the first moon landing. It was mostly a light comedy, but enjoyable.
"PDP-9 supplied by {some company specialising in supplying older
computers/replicas as props}"

The PDP-9 was provided by Max Burnett who worked for DEC in Australia
for many years (for some of these he was the regional head)
and now runs a company providing Classic Computers for films/TV/etc.

Post by Bernie Dwyer
My IT career only started in 1984, so I couldn't recognise a PDP-9 if I
tripped over one. Is that the sort of gear that such a facility would
use in 1969? I know that the Parkes radio-telescope was specially
upgraded by NASA for its role.

It is my understanding from talking to Max that there was indeed a
PDP-9 at Parkes during this time, although I'm fairly sure that the
actual PDP-9 used in the film was originally from La Trobe Univeristy
as I recognised the coloured dots on the DECtape drive which indicated
the local code for various DECtapes (RED = System tape, etc).

Post by Bernie Dwyer
There was a dramatic moment where the UPS didn't cut over, and "the
computer lost all its settings when the power failed", so the staff
spent 12 hours re-calculating where to point the dish, only to be saved
when the NASA rep pointed at the moon and said something like "there's
your reference point - they've got to be within 3 or 4 degrees".

I believe that this is a reasonably accurate description of what happened.
The only thing I don't understand is why all the data was lost (PDP-9s
have magetic core memory - perhaps it became corrupt?).

One story about the La Trobe University PDP-9. In the early days
the PDP-9 lived in a basement and one weekend it was flooded - up to
about the level of the desk. The -9 was taken outside, stripped into
component parts and dried. After reassembly, one flip-chip appeared to
be not required and the -9 ran for about 10 years with the flip-chip
sitting in a cupboard....

[Bernie Dwyer]

Post by h***@kerberos.davies.net.au

Post by Bernie Dwyer
I watched a film t'other night - "The Dish" - about the role played by
the radio-telescope facility at Parkes, New South Wales, Australia in
the first moon landing. It was mostly a light comedy, but enjoyable.
"PDP-9 supplied by {some company specialising in supplying older
computers/replicas as props}"

The PDP-9 was provided by Max Burnett who worked for DEC in Australia
for many years (for some of these he was the regional head)
and now runs a company providing Classic Computers for films/TV/etc.

Ah, so. Would he be interested in my Toshiba 2130CT (486, 32MB, 504MB,
colour) laptop ? ;-)

When I visited Parkes in '02, some of the props (control boards, etc)
were displayed in the visitor centre.

<snip>

Post by h***@kerberos.davies.net.au
One story about the La Trobe University PDP-9. In the early days
the PDP-9 lived in a basement and one weekend it was flooded - up to
about the level of the desk. The -9 was taken outside, stripped into
component parts and dried. After reassembly, one flip-chip appeared to
be not required and the -9 ran for about 10 years with the flip-chip
sitting in a cupboard....

DEC's only PDP-8.75 ?

Post by h***@kerberos.davies.net.au
--
Melbourne | "If soccer was meant to be played in the
Australia | air, the sky would be painted green"

[Rob Storey]

Post by h***@kerberos.davies.net.au

Post by Bernie Dwyer
"PDP-9 supplied by {some company specialising in supplying older
computers/replicas as props}"

The PDP-9 was provided by Max Burnett who worked for DEC in Australia
for many years (for some of these he was the regional head)
and now runs a company providing Classic Computers for films/TV/etc.

Max now provides the PDP-9 to the Monash Universty historical computing
exhibit.

It is on display in the foyer of the fourth(?) floor of one of the
buildings at the Caulfield campus (Melbourne), along with numerous other
items.

Rob Storey

[Tony Gallagher]

Post by Rob Storey

Post by h***@kerberos.davies.net.au

Post by Bernie Dwyer
"PDP-9 supplied by {some company specialising in supplying older
computers/replicas as props}"

The PDP-9 was provided by Max Burnett who worked for DEC in Australia
for many years (for some of these he was the regional head)
and now runs a company providing Classic Computers for films/TV/etc.

Max now provides the PDP-9 to the Monash Universty historical computing
exhibit.
It is on display in the foyer of the fourth(?) floor of one of the
buildings at the Caulfield campus (Melbourne), along with numerous other
items.
Rob Storey

Some foot notes ...

A PDP-9 was used with the Dish in 1969. Max Burnet has a video which was made for the ABC Collectors TV show. In this video he describes how he was asked by the movie producers if he could provide a PDP-9 for making the movie The Dish and he says he was able to provide the original one from the Dish at Parkes.

Max also co-produced a booklet in 2011, titled "A History of Digital in Australia and New Zealand". I am reading it at the moment. Here are some quotes from the book regarding The Dish and its computer.

Page 19
"PDP-9 serial number 161, CSIRO Division of Radio Physics, Parkes NSW (at The Dish)"

“The PDP–9 at Parkes became a film star 20 years later when it featured in the movie The Dish. Max Burnet was able to provide the PDP–9 for the film set from his museum collection. (Watch the credits at the end of the movie.) In the movie the PDP–9 was accused of losing data due to a power outage. Not so, it had core memory in real life. “

Sadly, Max passed away a few days ago. He leaves a rich legacy of material on computing history as well as many other achievements. I worked at DEC Australia for 17 years and Max 31 years. He was very highly respected by everyone.

Tony Gallagher

[Peter Flass]

Post by Tony Gallagher
Sadly, Max passed away a few days ago. He leaves a rich legacy of
material on computing history as well as many other achievements. I
worked at DEC Australia for 17 years and Max 31 years. He was very
highly respected by everyone.

:-(

[Jack Russell]

I was working on PDP-9s in the UK about then, I would have thought they
were a bit new for 1969 especially given NASA's (understandably)
conservative attitude. When I saw the movie I did wonder about that but
did not let it spoil an enjoyable movie. I did ask someone who worked on
the station in West Australia (Caernarvon?) but he could not remember.

Jack Russell

Post by Bernie Dwyer
I watched a film t'other night - "The Dish" - about the role played by
the radio-telescope facility at Parkes, New South Wales, Australia in
the first moon landing. It was mostly a light comedy, but enjoyable.
"PDP-9 supplied by {some company specialising in supplying older
computers/replicas as props}"
My IT career only started in 1984, so I couldn't recognise a PDP-9 if I
tripped over one. Is that the sort of gear that such a facility would
use in 1969? I know that the Parkes radio-telescope was specially
upgraded by NASA for its role.
There was a dramatic moment where the UPS didn't cut over, and "the
computer lost all its settings when the power failed", so the staff
spent 12 hours re-calculating where to point the dish, only to be saved
when the NASA rep pointed at the moon and said something like "there's
your reference point - they've got to be within 3 or 4 degrees".
Harumph!

[Brian Inglis]

On Mon, 05 Jan 2004 15:18:26 +1000 in alt.folklore.computers, Bernie

Post by Bernie Dwyer
I watched a film t'other night - "The Dish" - about the role played by
the radio-telescope facility at Parkes, New South Wales, Australia in
the first moon landing. It was mostly a light comedy, but enjoyable.
"PDP-9 supplied by {some company specialising in supplying older
computers/replicas as props}"
My IT career only started in 1984, so I couldn't recognise a PDP-9 if I
tripped over one. Is that the sort of gear that such a facility would
use in 1969?

Check it out yourself at http://www.parkes.atnf.csiro.au/apollo11
"the observatory's new PDP-9 computer (the observatory's first
computer, purchased by John Shimmins in 1967 and arriving in April
1968)."

[Russ Holsclaw]

"Brian Inglis" <***@SystematicSw.ab.ca> wrote in
message > >I watched a film t'other night - "The Dish" -
about the role played by

Post by Brian Inglis

Post by Bernie Dwyer
the radio-telescope facility at Parkes, New South Wales,

Australia in

Post by Brian Inglis

Post by Bernie Dwyer
the first moon landing. It was mostly a light comedy, but

enjoyable.

Post by Brian Inglis

Post by Bernie Dwyer
"PDP-9 supplied by {some company specialising in

supplying older

Post by Brian Inglis

Post by Bernie Dwyer
computers/replicas as props}"
My IT career only started in 1984, so I couldn't

recognise a PDP-9 if I

Post by Brian Inglis

Post by Bernie Dwyer
tripped over one. Is that the sort of gear that such a

facility would

Post by Brian Inglis

Post by Bernie Dwyer
use in 1969?

Check it out yourself at

http://www.parkes.atnf.csiro.au/apollo11

Post by Brian Inglis
"the observatory's new PDP-9 computer (the observatory's

first

Post by Brian Inglis
computer, purchased by John Shimmins in 1967 and arriving

in April

Post by Brian Inglis
1968)."

The Dish is a wonderfully entertaining film, and at least
somewhat accurate historically. However, the bit about the
power failure, the loss of the computer, and having to
calculate how to point the dish were all added by the
scriptwriters for both comedy and dramatic tension. The
account given at the above web address makes no mention of
these events, and I doubt that anything like that happened,
and certainly not the way depicted. There was also a much
larger crew at Parkes, including several NASA techs, not
just the one guy.

What _is_ true, however, is the danger they encountered when
the winds started to blow at speeds beyond the design-limits
of the telescope. Normally, they would have parked the dish
pointing straight up until the winds died down, but then
they would have missed out on the TV images of Neil
Armstrong's footprints on the moon. When the EVA started,
the moon was just coming over the horizon, so the dish had
to be pointed at a low angle. At first, it was at a lower
angle than the dish could really point. They got an extra
bit of "low-angle" capability by using an off-axis receiver
that they happened to have, which could pick up signals off
the main axis of the dish. After the moon rose a bit
further, they were able to switch to the main receiver,
which provided a better signal. This detail about the
off-axis receiver is actually mentioned in the movie dialog,
but is easy to miss if you don't know what they're talking
about. At any rate, those of us who remember watching the
first moonwalk recall that the TV images were pretty
indistinct at first, and then suddenly got much clearer.
Now, we know why.

According to the website, the winds were so gusty that
someone had to steer the dish using manual controls, and
couldn't look up from what he was doing long enough to look
at the TV monitor. He had to see it on video later.

[John Savard]

On Mon, 05 Jan 2004 15:18:26 +1000, Bernie Dwyer

Post by Bernie Dwyer
My IT career only started in 1984, so I couldn't recognise a PDP-9 if I
tripped over one. Is that the sort of gear that such a facility would
use in 1969?

It is entirely possible.

A PDP-9 computer had an 18-bit word length. Unlike the PDP-8, with a
12-bit word length, it had an instruction set that didn't require
certain awkwardnesses that the 3-bit opcode of the PDP-8 led to. It
did arithmetic on 18-bit integers, and a hardware floating-point unit
was available for it as an option. With up to 262,144 words of
storage, it was able to do serious work.

Such a machine, costing tens of thousands of dollars, would not have
been as powerful as an IBM mainframe computer - their top-of-the-line
machine from that era, the 360/195, is roughly comparable to a Pentium
in design, with pipelining and cache and an accelerated floating-point
unit - but as those cost millions of dollars, they would not be used
if they were not needed.

Even the smaller PDP-8 computer, with its limitations, was used in
many automatic control applications.

John Savard
http://home.ecn.ab.ca/~jsavard/index.html

[Geoffrey G. Rochat]

Post by John Savard
A PDP-9 computer had an 18-bit word length. Unlike the PDP-8, with a
12-bit word length, it had an instruction set that didn't require
certain awkwardnesses that the 3-bit opcode of the PDP-8 led to. It
did arithmetic on 18-bit integers, and a hardware floating-point unit
was available for it as an option. With up to 262,144 words of
storage, it was able to do serious work.

Nope. The PDP-9 could only address 32KW, in Extend Mode with a KG09 option
Memory Extension Control, and had a directly-addressable bank size of 8KW.
(Not quite as challenging, or as intriguing, as a PDP-8's page size of 128W,
but not an infinite flat expanse of memory, either.) AFAIK, the PDP-9 did
not have floating-point hardware, although the KE09 option added an Extended
Arithmetic Element for multiplication, division, multi-place shifts,
normalization, etc.

Among the more interesting facets of the PDP-9 were that it was
microprogrammed with a 64-word rope memory "ROM", was all discrete
transistors, and had both twos-complement and - as part of it's heritage as
4th generation successor to the PDP-1 - ones-complement arithmetic.

The PDP-9's successor was the PDP-15, a TTL machine with an index register
and a 4KW bank size. Using indexing and indirection it could address 128KW
(and I've heard of customized versions that supported 256KW), and certain
flavors of -15s could do floating-point as well. But, IIRC, the PDP-15
didn't make it's debut until 1972 or so, just as the Apollo program was
winding down.

[Alfred Falk]

Post by Geoffrey G. Rochat

Post by John Savard
A PDP-9 computer had an 18-bit word length. Unlike the PDP-8, with a
12-bit word length, it had an instruction set that didn't require
certain awkwardnesses that the 3-bit opcode of the PDP-8 led to. It
did arithmetic on 18-bit integers, and a hardware floating-point unit
was available for it as an option. With up to 262,144 words of
storage, it was able to do serious work.

Nope. The PDP-9 could only address 32KW, in Extend Mode with a KG09
option Memory Extension Control, and had a directly-addressable bank
size of 8KW. (Not quite as challenging, or as intriguing, as a PDP-8's
page size of 128W, but not an infinite flat expanse of memory,
either.) AFAIK, the PDP-9 did not have floating-point hardware,
although the KE09 option added an Extended Arithmetic Element for
multiplication, division, multi-place shifts, normalization, etc.
Among the more interesting facets of the PDP-9 were that it was
microprogrammed with a 64-word rope memory "ROM", was all discrete
transistors, and had both twos-complement and - as part of it's
heritage as 4th generation successor to the PDP-1 - ones-complement
arithmetic.

And if 18-bit integer arithmetic was what you needed, it was really very
fast for it's day. (1 microsecond cycle time. Most instructions
completing in 1 or 2 cycles.)

I have a few PDP-9 momentos: A couple of R-series Flip-Chips and when I
work on the AlphaServers for which I am responsible, I sit in the chair
that came with a PDP-9. Not from the -9 that I worked with long ago,
though.

Post by Geoffrey G. Rochat
The PDP-9's successor was the PDP-15, a TTL machine with an index
register and a 4KW bank size. Using indexing and indirection it could
address 128KW (and I've heard of customized versions that supported
256KW), and certain flavors of -15s could do floating-point as well.
But, IIRC, the PDP-15 didn't make it's debut until 1972 or so, just as
the Apollo program was winding down.

My recollection suggests as early as 1970, but considering their cost,
computers were kept in service much longer in those days.

[Jack Russell]

Post by Alfred Falk
I have a few PDP-9 momentos: A couple of R-series Flip-Chips and when I
work on the AlphaServers for which I am responsible, I sit in the chair
that came with a PDP-9. Not from the -9 that I worked with long ago,
though.

Ah, the chair! I had forgotten all about that little beauty. You did not
get one with PDP-8s and I cannot remember if you got one with PDP-10s.

Jack Russell

[Jack Peacock]

Post by Jack Russell
Ah, the chair! I had forgotten all about that little beauty. You did not
get one with PDP-8s and I cannot remember if you got one with PDP-10s.

Our company bought one of the DEC 11/34 COS (small business RT-11XM/Dibol)
systems back in 1977. It came with two VT52s and a special table where you
could hang docs in a narrow cabinet in the back. The 11/34 is long gone, as
are the VTs (good riddance) but we still have that table. These days it
holds the coffee pot and the microwave. I can safely claim the DEC table
has been in production mode, used nearly every day for the entire 26+ years
we've had it. Still in good condition too. And not a single maintenance
call logged to date!
Jack Peacock

[Brian Inglis]

On Wed, 07 Jan 2004 20:46:29 GMT in alt.folklore.computers, Alfred

Post by Alfred Falk

Post by Geoffrey G. Rochat
The PDP-9's successor was the PDP-15, a TTL machine with an index
register and a 4KW bank size. Using indexing and indirection it could
address 128KW (and I've heard of customized versions that supported
256KW), and certain flavors of -15s could do floating-point as well.
But, IIRC, the PDP-15 didn't make it's debut until 1972 or so, just as
the Apollo program was winding down.

My recollection suggests as early as 1970, but considering their cost,
computers were kept in service much longer in those days.

Manufactured in 1970 -- one source says first delivery in February