to deploy a 2nd hand Cray-1 at UQ, we had to raise the ex-IBM 3033 floor, it turned out the bend radius for flourinert was NOT the same as a water cooled machine. We also installed a voltage re-generator which is basically a huge spinning mass, you convert Australian volts to DC, spin the machine, and take off re-generated high frequency volts for the cray, as well as 110v on the right hz for boring stuff alongside. the main bit ran off something like 400hz power, for some reason the CPU needed faster mains volts going in.
The flourinert tank has a ball valve, like a toilet cistern. we hung a plastic lobster in ours, because we called the cray "Yabbie" (Queensland freshwater crayfish)
That re-generator, the circuit breakers are .. touchy. the installation engineer nearly wet his trousers flipping on, the spark-bang was immense. Brown trouser moment.
The front end access was Unisys X11 Unix terminals. They were built like a brick shithouse (to use the australianism) but were a nice machine. I did the acceptance testing, it included running up X11 and compiling and running the largest Conways game of life design I could find on the net. Seemed to run well.
We got the machine as a tax-offset for a large Boeing purchase by Australian defence. End of life, one of the operators got the love-seat and turned it into a wardrobe in his bedroom.
Another, more boring cray got installed at department of primary industries (Qld government) to do crops and weather modelling. The post cray-1 stuff was .. more ordinary. Circular compute unit was a moment in time.
400 Hz is really the next best thing to a switching supply, as the transformers and filter capacitors can be smaller than they would need to be at 50/60 Hz. It can save cost and space for filter capacitors, especially in a three-phase system where there's not as much ripple to deal with.
Another rationale may have been that the flywheel on the motor-generator would cover a multitude of power-quality sins.
> the main bit ran off something like 400hz power, for some reason the CPU needed faster mains volts going in.
Aerospace originally did that to reduce component size, CDC and IBM took advantage of the standard in the early 60's.
Strangely, it seems mainframes didn't adopt switching power supplies until the end of the 70's, despite the tech being around since the end of the 60's.
I used a Cray C-90 and T3D 256-core machine from 1995-1999. The T3D used commodity Alpha 21164, and was already behind the T3E when we got it (Cray refurbished.) By the end it was outclassed by an SGI Oxygen box with 8 CPUs. I’d already ported a lot of software from SunOS and HP-UX to Irix and Unicos (Cray) and it was easy to move it to Linux in the end.
IIRC the desk side onyx had the royal purple stripes and only accepted one CPU board, the rack mount version were that blue-purple color, more indigo (color)
So there were two computers made with the same bits mid 90s. Origin(compute, blue) and onyx(graphics, purple). Both had deskside and rack systems.
Onyx had a few slots reserved for graphics, original could have more compute boards. But you could certainly put two couple cpu boards in an onyx deskside or rack.
It must have been more complex then that, I was at the skywalker ranch when onyx was being replaced by o200/2000 and never saw a purple onyx at Kerner(ILM), I had a purple Indy impact as my home machine and was looking for purple. I hated teal with a passion.
Perhaps all the purple rack onyx had been dumped but we dug through ILMs boneyard looking to add to our cxfs cluster, but the FC bus speed was too low.
It is possible that R10k was different or that there were multiple chassis. The desk sides I had experience with required RAM in slot 1, with CPU in slot 2, with up to 4 CPUs on the board.
o200 was more restrictive, with 2 CPUs per chassis, with the ability to cray-link two chassis for a total of 4 CPUs, more required o2000.
But this was a quarter of a century ago or more by now…so I may misremember things.
I actually forgot that they made a low end ‘Indy’ and never saw one. We called the Indigo2 Indy
There were some oddities with ad dollars and prestige clients in the 90s, where systems would be upgraded, avoiding swapping out the serialized, asset tagged parts, yet upgrading systems.
The teal Indigo2s were the original with the impact graphics ones being purple.
But all the Indigo2s I saw typically were r10k + max impact graphics despite the color.
The cases were identical.
But Evans & Sutherland and Lucas are the only places I dealt with SGI, so probably not a good source for typical customer’s experience
There a lot of discussion here https://retrocomputing.stackexchange.com/questions/7412/why-... but nothing seems conclusive.. I would wager the last answer, "IBM was using 400Hz", to be most directly causal reason. The motor-generator configuration might provide galvanic isolation and some immunity to spikes and transients as well?
Smaller transformers and capacitors in all the linear power supplies.
400Hz is still common in aircraft. Distribution losses are higher, but you're going across the room, not across the country.
There you go. Not to doubt what you say, but we definitely had the love seat yet we also had a tank of vaguely flourescing green liquid. Maybe we had some intermediate state, the cray-1 cpu form but the cray-2 upgraded coolant.
It wouldn't surprise me if we had the bastard love-child of leftovers from Boeing.
The GP also mentions X11 Terminals. My wiki-fu shows the X Windowing System came about on or around 1983, while Cray-1 was 1970s vintage. I assume that was an upgrade at some later point.
X Window Release 3 (X11R3) was introduced on Cray into UNICOS (a UNIX variant of Cray OS, COS) in late 1989 using ported 64-bit Xlib. But it was not widely used within small Cray community.
But MIT cooked up X11 "PROTOCOL" of Xlib in late 1985 to 1986 on Univac and Unix in C with many other X libraries written in Common Lisp.
X10R3 mostly stabilized the Xlib around a few platforms and CPU architecture (DDX) in a"long" preparation for X11R1 in September 1987.
It was fat finger memory. it was X10R3 or something similar, which I had previously used in UCL on Ultrix machines in the 80s. I don't think it was R5, I don't think much got upgraded in that space but .. it was a long time ago.
This was a SECOND HAND cray. It was a tax contra made in the 90s when Boeing sold a lot of stuff to the Australian Defence forces, and to avoid a massive tax burden donated science trash to the uni.
The flourinert tank has a ball valve, like a toilet cistern. we hung a plastic lobster in ours, because we called the cray "Yabbie" (Queensland freshwater crayfish)
That re-generator, the circuit breakers are .. touchy. the installation engineer nearly wet his trousers flipping on, the spark-bang was immense. Brown trouser moment.
The front end access was Unisys X11 Unix terminals. They were built like a brick shithouse (to use the australianism) but were a nice machine. I did the acceptance testing, it included running up X11 and compiling and running the largest Conways game of life design I could find on the net. Seemed to run well.
We got the machine as a tax-offset for a large Boeing purchase by Australian defence. End of life, one of the operators got the love-seat and turned it into a wardrobe in his bedroom.
Another, more boring cray got installed at department of primary industries (Qld government) to do crops and weather modelling. The post cray-1 stuff was .. more ordinary. Circular compute unit was a moment in time.
(I think I've posted most of this to HN before)