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I worked on the ParSys SuperNode in the early 90's, a 96-Transputer machine with a reconfigurable network switch that meant that any 4-regular graph could be re

I worked on the ParSys SuperNode in the early 90's, a 96-Transputer machine with a reconfigurable network switch that meant that any 4-regular graph could be realised in hardware. So the network of transputers could be anything you wanted ... you could configure it to suit your problem. I learned Occam and wrote some programs for it, but one of my main tasks was to port the NAG serial ForTran library to the machine. If it was going to be used for scientific work, that was regarded as essential. I remember one occasion when running an "ls" command on a directory not only crashed the machine, but wiped the hard-drive. The OS at the time was a home-grown unix-a-like, and the internal tables for "ls" were fixed size. The NAG library had do many files in a directory, the tables were overflowed and system memory got over-written. The machine was on the network, although it wasn't possible to login remotely, so to use it you had to be in the room. It got to the point where when people saw me coming they backed up all their work across the network and logged off ... they knew it wouldn't be long before the machine would crash and need a hard restore. The T800 series didn't have memory protection, and didn't have floating point, so using it for scientific calculations seemed doomed. Worse, every time someone brought be a program for parallelisation, I could refactor it and get a 100 to 10,000 times speed-up on a serial machine ... the parallel machine wasn't needed. It was a beautifully conceived machine, and I desperately wanted it to succeed, but it ended up being nibbled to death by circumstances and never found the niche it needed. I still occasionally thumb through some of the books I have. Possibly I should donate them to a computing museum. Or sell them.

jandrewrogers 3y ago
> ...every time someone brought be a program for parallelisation, I could refactor it and get a 100 to 10,000 times speed-up on a serial machine... That is a good summary of my experience working in HPC. Many HPC codes had a strong "just throw hardware at it" vibe with relatively little effort put into maximizing performance of individual nodes. There were a couple cases where the optimized code ran faster on my laptop than the supercomputer with the original code. Expensive network interconnects have diminishing returns if you don't do the software design work. Another recurring issue was that the process nodes for exotic silicon was usually a few generations behind the state-of-the-art for commodity silicon, so even if I could get the exotic silicon to perform at its theoretical limits, the commodity silicon was sufficiently superior at the basics that you lost most of the advantages of the exotic architecture in practice with good performance engineering.
fanf2 3y ago
The T800 series did have floating point, and as I understand it, it was one of the most extensive uses of formal methods in processor design of its era http://www.transputer.net/tn/06/tn06.html http://www.transputer.net/tn/06/tn06.html The rough guide to transputers is, T2: 16 bit; T4: 32 bit; T8: FPU; T9: superscalar.
- ColinWright 3y ago
  You're absolutely right, I was mistaken. Now I'm trying to remember if out SuperNode had T4s or T8s. I might have to dig out my notes.
  - helf 3y ago
    Please do. I am fascinated by computer history and finding info from people who worked with them is always welcome. What books do you have? I might be interested in buying them from you :)
    - rbanffy 3y ago
      From https://www.researchgate.net/publication/3358994_Parallelising_a_set_of_2-D_frequency_transforms_in_a_flexible_manner https://www.researchgate.net/publication/3358994_Parallelisi... it looks like it was the 805.

jandrewrogers 3y ago

> ...every time someone brought be a program for parallelisation, I could refactor it and get a 100 to 10,000 times speed-up on a serial machine... That is a good summary of my experience working in HPC. Many HPC codes had a strong "just throw hardware at it" vibe with relatively little effort put into maximizing performance of individual nodes. There were a couple cases where the optimized code ran faster on my laptop than the supercomputer with the original code. Expensive network interconnects have diminishing returns if you don't do the software design work. Another recurring issue was that the process nodes for exotic silicon was usually a few generations behind the state-of-the-art for commodity silicon, so even if I could get the exotic silicon to perform at its theoretical limits, the commodity silicon was sufficiently superior at the basics that you lost most of the advantages of the exotic architecture in practice with good performance engineering.

fanf2 3y ago

The T800 series did have floating point, and as I understand it, it was one of the most extensive uses of formal methods in processor design of its era http://www.transputer.net/tn/06/tn06.html http://www.transputer.net/tn/06/tn06.html The rough guide to transputers is, T2: 16 bit; T4: 32 bit; T8: FPU; T9: superscalar.

ColinWright 3y ago
You're absolutely right, I was mistaken. Now I'm trying to remember if out SuperNode had T4s or T8s. I might have to dig out my notes.
- helf 3y ago
  Please do. I am fascinated by computer history and finding info from people who worked with them is always welcome. What books do you have? I might be interested in buying them from you :)
  - rbanffy 3y ago
    From https://www.researchgate.net/publication/3358994_Parallelising_a_set_of_2-D_frequency_transforms_in_a_flexible_manner https://www.researchgate.net/publication/3358994_Parallelisi... it looks like it was the 805.