The Cray-1 Computer System (1977) [pdf]

(s3data.computerhistory.org)

129 points | by LordGrey 4 days ago ago

73 comments

  • ggm 16 hours ago ago

    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.

    (I think I've posted most of this to HN before)

    • FarmerPotato 13 hours ago ago

      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.

      • Grosvenor an hour ago ago

        You means SGI onyx? The cool looking purple one?

    • bilegeek 15 hours ago ago

      > 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.

    • kev009 15 hours ago ago

      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?

      • Animats 11 hours ago ago

        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.

    • Polizeiposaune 14 hours ago ago

      Cray-1 or Cray-2? IIRC Fluorinert was new with the Cray-2, while wikipedia suggests that the Cray-1 used a freon as coolant.

      • ggm 13 hours ago ago

        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.

        • maybewhenthesun 8 hours ago ago

          You consistency in spelling fluor as flour gave me visions of using pancake batter as a coolant :-D

      • pklausler 2 hours ago ago

        Cray old-timer here; 'nert was definitely Cray-2 and later. In the Cray-3 it was turned into mist.

      • xattt 5 hours ago ago

        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.

        • egberts1 4 hours ago ago

          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.

          https://www.x.org/wiki/X11R1/?utm_source=chatgpt.com

        • bluGill 4 hours ago ago

          Since this was a 2nd hand machine having the upgrades for X11 doesn't seem unlikely.

    • CamperBob2 15 hours ago ago

      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.

    • markus_zhang 13 hours ago ago

      Hello Bandit!

  • DonHopkins 14 hours ago ago

    I knew a guy who worked at one of the national labs that had its own Cray supercomputer, in a computer room with a big observation window that visitors could admire it through, of course (all Crays required observations windows to show them off).

    Just before a tour group came by, he hid inside the Cray, and waited for them to arrive. Then he casually strolled out from the back of the Cray, pulling up the zipper of his jeans, with a sheepish relieved expression on his face, looked up and saw the tour group, acted startled, then scurried away.

    • technofiend 11 hours ago ago

      The Cray 1-ish machines I had access to at Shell and Chevron were most definitely tucked away in rooms with no visibility into them. In fact the Chevron machine room had pretty stern "no photography" placards, which I took seriously and is sadly why I don't have a photo of sitting on the loveseat of their machine.

      Getting access took just short an act of God and I was a sysadmin in the central support group! They didn't want us puttering on the machines, so as far as I could tell it mostly sat idle.

  • twoodfin 16 hours ago ago

    The CRAY-1 was so ridiculously ahead of its time that it took until the Pentium MMX (1997) for “ordinary” computers to catch up to its raw performance.

    That’s 20 years or about 10,000X the available VLSI transistors via Moore’s Law.

    • antonvs an hour ago ago

      > The CRAY-1 was so ridiculously ahead of its time that it took until the Pentium MMX ...

      You'd need a different comparison to show how the Cray-1 was special. If the comparison is to single commodity CPUs, like the Pentium MMX, you could make much the same comparison for many mainframes and supercomputers. Several supercomputers in the 1980s exceeded 1 GFLOP, for example, and it wasn't until the 2000s that you could get commodity CPUs with that performance.

    • chasil 14 hours ago ago

      Seymour Cray never designed a silicon microprocessor. I wonder what he would have created had that opportunity presented itself.

      https://en.wikipedia.org/wiki/Seymour_Cray

      • __patchbit__ 12 hours ago ago

        In his memory some have said his name are the last two characters in RISC and CISC.

    • firecall 15 hours ago ago

      I wonder how many times faster my iPhone 17 Pro Max is?

      Sometimes I like to remind myself we are living in the future. A future that seemed like SciFi when I was a kid in the 70s!

      Sadly I don’t think we will ever see Warp Drives, Time Travel or World Peace. But we might get Jet Packs!

      • wmoxam 15 hours ago ago

        Recently I've found myself wanting a tricorder type device.

        • esseph 11 hours ago ago

          With the visual analysis of LLMs, throw in some extra ingredients with a camera, microphone, speaker, and display, and were getting close. Add Bluetooth for biosensors and... Iterate a couple of generations...

          We're getting there!

      • hypersoar 15 hours ago ago

        From the Wikipedia article on the Cray 1:

        "The 160 MFLOPS Cray-1 was succeeded in 1982 by the 800 MFLOPS Cray X-MP, the first Cray multi-processing computer. In 1985, the very advanced Cray-2, capable of 1.9 GFLOPS peak performance

        ...

        By comparison, the processor in a typical 2013 smart device, such as a Google Nexus 10 or HTC One, performs at roughly 1 GFLOPS,[6] while the A13 processor in a 2019 iPhone 11 performs at 154.9 GFLOPS,[7] a mark supercomputers succeeding the Cray-1 would not reach until 1994."

        • hulitu 11 hours ago ago

          > while the A13 processor in a 2019 iPhone 11 performs at 154.9 GFLOPS,[

          Sustained ? Or just for some ms when the thermals kick in ?

      • FridayoLeary 15 hours ago ago

        At the risk of sounding cliche i'll point out that ios probably uses several times the capacity of a cray 1 just to get the keyboard to work.

        • estimator7292 13 hours ago ago

          Yes, but the impressive part is that the iPhone does it on a few mW instead of a few MW

      • qsera 14 hours ago ago

        >how many times faster my iPhone 17 Pro Max is..

        Sadly most of that power is not working for you, most of the time, but working against you, by spying, tracking and manipulating you.

        Bet that was not include in your sci-fi dreams in 70s..

        • FarmerPotato 13 hours ago ago

          Oh but we had The Forbin Project, its sequel Colossus, and later Wargames. Not to mention Star Trek episodes with malignant computers. And I have No Mouth But I Must Scream.

          In the 70s, science fiction fed me Cold War fears of world-controlling mainframes.

        • Angostura 9 hours ago ago

          I'd love to see you substantiate that - bet you can't.

          • timbit42 2 hours ago ago

            I certainly can't. I'm running GrapheneOS.

    • fnord77 15 hours ago ago

      Not terribly impressive considering an average 20 year old super computer c. 2005 is still about 100x as fast as today's best consumer cpus

      • twoodfin 15 hours ago ago

        Well, yeah, Dennard scaling ended around 20 years ago!

  • W-Stool 4 hours ago ago

    If these kinds of machines interest you I highly recommend the book "The Supermen" by Charles Murray. It has all the details you would ever want on Seymour Cray and others in the business.

    I was working at a geophysical company in the 80's and we lusted after a Cray-1. Best we could afford where array processors (CSPI) connected to VAX systems.

  • effnorwood 16 hours ago ago

    Blew my mind age 4. Then found out about the imos transputer. And robotics magazine. 70's were popping. Ponging?

    • lukeh 15 hours ago ago

      XMOS is still keeping the Inmos dream alive, more or less!

    • SirIsaacGluten 15 hours ago ago

      Inmos not imos, if my memory cells serve ne correctly. I lived overseas at the time, so I did not hear about the Cray till like 1980/81. My friend (we were like 12) had an idea to write a simulator for digital circuits, and I was puzzled as to why you would want to simulate a circuit when you can build it and test it. He was way ahead of his time.

  • zippyman55 11 hours ago ago

    My first time on Cray, I thought I had a core dump, my program ended so quickly. No, the job had finished.

    • jeffrallen 11 hours ago ago

      Same with "go test". :)

  • lebuffon 2 hours ago ago

    I quickly skimmed the instruction set and did not see anything resembling a sub-routine call or branch and link instruction.

    Did I miss it?

    • HarHarVeryFunny an hour ago ago

      The "R exp" is subroutine call (which saves return address to register B00), and I believe "J Bjk" is the subroutine return.

      The Cray-1 didn't have a hardware stack, so subroutine call is basically just jump there and back, using a register for the return address rather than pushing/popping it to/from the stack.

      Another oddity of the instruction set that stands out (since I'm in process of defining a VM ISA for a hobby project) is that the branch instructions test a register (A0 or S0) rather than look at status flags. In a modern CPU a conditional branch, if (x < y), is implemented by compare then branch where the compare instruction sets flags as if it had done a subtraction, but doesn't actually modify the accumulator. In the Cray this is evidentially done by doing an actual subtraction, leaving the result in A0, then branching by looking at the value of A0 (vs looking at flags set by CMP).

      Gemini explains this as being to help pipelining.

    • antonvs 43 minutes ago ago

      Subroutine calls are for the weak :)

      There's some more detail here: https://ed-thelen.org/comp-hist/CRAY-1-HardRefMan/CRAY-1-HRM...

      The following quote gives some sense of how "manual" this was:

      > "On execution of the return jump instruction (007), register Boo is set to the next instruction parcel address (P) and a branch to an address specified by ijkm occurs. Upon receiving control, the called routine will conventionally save (Boo) so that the Boo register will be free for the called routine to initiate return jumps of its own. When a called routine wishes to return to its caller, it restores the saved address and executes a 005 instruction. This instruction, which is a branch to (Bjk), causes the address saved in Bjk to be entered into P as the address of the next instruction parcel to be executed."

      Details were up to the compiler that produced the machine code.

  • october8140 15 hours ago ago

    > The aesthetics of the machine have not been neglected. The CPU is attractively housed in a cylindrical cabinet. The chassis are arranged two per each of the twelve wedge-shaped columns. At the base are the twelve power supplies. The power supply cabinets, which extend outward from the base are vinyl padded to provide seating for computer personnel.

    • t1234s 4 hours ago ago

      Answers my question.. I always thought they can't possibly want people sitting on something so expensive.

    • postexitus 7 hours ago ago

      It looks really nice - but never understood the seating. Who came up with that?

      • wongarsu 4 hours ago ago

        It ensures the Cray is placed as the centerpiece of the room, not as mere equipment shoved on the wall

        • postexitus 3 hours ago ago

          Probably they could achieve the same with circular construction but without the seats.

  • 5- 13 hours ago ago

    for a much more in-depth description of its predecessor, see https://archive.computerhistory.org/resources/text/CDC/cdc.6...

    i don't think there is a comparable book about the cray-1?

  • LgWoodenBadger 3 hours ago ago

    In college I had an account on our ACM chapter's DEC Alpha, which I used primarily for mudding. Its DNS name was cray-ymp.xxx.xxx.edu, which resulted in more than a few moments of shock/consternation from mods. "You're mudding from a CRAY Y-MP???"

  • tvali 8 hours ago ago

    Compare this to modern system: we could fully simulate this kind of slow computer in real time, I would guess, with all the wheels, clockwork and mechanics as well as logic circuits with full electricity. Deciding the simulation level would be a bit challenging - is this an atomic, an electron or more common sense simulation -; still I think the simulation would work as well as this kind of document.

    • formerly_proven 2 hours ago ago

      Absolutely not on the electrical level. ISA emulation, probably, maybe, though these Crays are not IEEE machines so you have to actually fully emulate the floating point operations, instead of punting them to the FPU. That may make getting hundreds of MFLOPs on difficult.

  • feurio 10 hours ago ago

    > "The compact mainframe occupies a MERE 70 sq. ft. of floor space."

    (emphasis mine)

  • qingcharles 10 hours ago ago

    Am I right in thinking there are no working Cray-1s?

    I know a couple of museums have them, but I don't think any software has ever surfaced, am I right?

    • pinewurst 10 hours ago ago

      No, both COS (but missing Cray Fortran) and Unicos have been located.

  • awacs 13 hours ago ago

    I remember doing a report on this in high school in the late 80s. I'd love to do an order of magnitude comparison to a modern M4 Mac... Amazing how far we've come.

    • fghorow 8 hours ago ago

      I just did a BOTE calculation for my iPhone (A17 Pro chip; GPU rated at 4 Tflops). According to the sales blurbage in TFA, the Cray 1 performed at 80 Mflops. (Yes, that is OBVIOUSLY not comparing apples to Apples -- pun intended). Unless I've dropped a decimal point, my iPhone is (capable of) 50,000 times the floating point speed of a Cray 1.

      In my back pocket. To watch cat videos.

    • AnimalMuppet 4 hours ago ago

      I remember computer magazines of the time talking about "a Cray on a chip" in their April 1st jokes.

      Well... we're there. Far past, in fact. We live in the future that then was so far out of reach that people could only joke about it, not consider it a realistic possibility.

      In one lifetime.

    • TheOtherHobbes 9 hours ago ago

      Cray 1 - 160 MFLOPS

      M4 CPU - 280 GFLOPS

      M4 GPU - 2900 GFLOPS

    • hulitu 11 hours ago ago

      > I'd love to do an order of magnitude comparison to a modern M4 Mac... Amazing how far we've come.

      Yes, would be nice to compare the capabilities (multiuser, multitasking, security, RCE). Did we get _so_ far ? How many users can a Mac sustain ?

  • tvguide61 14 hours ago ago

    Why the thin black curtain on the window?

    Thoughts:

    1. To block some sunlight from getting in.

    2. It’s a secure facility and wanted to prevent people from looking in.

    3. To not have to look at something outside.

    4. It’s a secure facility and wanted to prevent the chance of taking a picture of someone or something outside that could compromise the location of the computer or someone’s identity; sometimes the first place a photogenic computer was built was at a customer site.

    • fredoralive 11 hours ago ago

      I suspect the curtains are closed to avoid causing exposure issues etc. in the photos being taken.

      As for windows in a computer room, seems a bit unusual, but a nicer working environment than the usual windowless box I'd guess...

      • bluGill 4 hours ago ago

        Many computer rooms had windows. Computers were expensive things that companies often wanted to show off - but they needed special rooms with raised floors, HVAC (which also make them look even more exclusive/impressive and worth showing off), and the cost (millions of dollars when senior operators might be making $50k/year) meant you wanted to be careful who could touch them. Thus a window so that you could bring outsiders by the room on the way to a meeting and they could look in and see that shiny equipment.

        Remember in 1980 the modern PC wasn't even invented (Apple II was) yes. Most people didn't have access to any terminal as part of their job, only specialized positions did. Typewriters where was everyone had on their desk. As such a computer was something a company could wow visitors with. Times have changed.

    • estimator7292 13 hours ago ago

      It was the 70s, and that was simply the style at the time.

    • ssl-3 14 hours ago ago

      Or, you know: Sometimes, a window shade is just a window shade.

  • bytesandbits 13 hours ago ago

    who was the industrial designer? Cray-1 fits so well it looks straight out of 2001: A space Odyssey

    • ckastner 10 hours ago ago

      somewhat related:

      "Seymour said he thought it was odd that Apple bought a Cray to design Macs because he was using Macs to design Crays. He sent me his designs for the Cray 3 in MacDraw on a floppy.” reports KentK.

      https://cray-history.net/2021/07/16/apple-computer-and-cray-...

    • themafia 12 hours ago ago

      Cray himself. Here's a talk about designing it. My favorite part is his description of the aluminum machining they had to invent in order to move the freon through the frame to keep the machine from melting. It's a great talk.

      https://www.youtube.com/watch?v=vtOA1vuoDgQ

    • idatum 12 hours ago ago

      In the past few years whenever I re-watch 2001 when Dave is shutting down HAL, I see a spaceship capable data center. And HAL sings "Daisy.." finally at the foundational, bare metal layer.

  • TZubiri 3 hours ago ago

    Before IBM's deep blue, apparently there was a chess program called Cray Blitz, I'm sure the cray had the raw power(20MHz? But with 64 parallel operations) needed to beat the top humans, but the software just wasn't there yet.

    Blitz was ported to C and continued development FOSS as Crafty, mainly by a U of Alabama professor, but to this day it can't beat top humans on modern cpu (topping at 2650 elo instead of 2850 of, say, carlsen.)

  • NL807 14 hours ago ago

    Documentation is fantastic.

  • DonHopkins 14 hours ago ago

    I had the cover of this pinned up on my wall! Supercomputer porn.