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The Cray 1 was way ahead of its time. It implemented SIMD vector instructions to speed up numerical computation, was liquid cooled, and ran at 80 MHz (in 1976).

The Cray 1 was way ahead of its time. It implemented SIMD vector instructions to speed up numerical computation, was liquid cooled, and ran at 80 MHz (in 1976). The chief architect, Seymour Cray, was kind of a genius, and is responsible for designing many other pioneering machines. Also, fun fact, it didn't have a CPU. It used all discrete logic chips, and was wired by hand, with lots and lots of wire. IIRC Seymour Cray liked to hire women to do the wiring job, because they had an easier time fitting inside the computer core to wire it, and doing detailed work because they had smaller hands.

msla 3y ago
> Also, fun fact, it didn't have a CPU. It used all discrete logic chips, and was wired by hand, That's how CPUs were built back then. What it didn't have was a single-chip CPU, or a microprocessor. Next up: "The Model T Ford didn't have an engine, it had this gasoline-burning device to provide motive power."
drfuchs 3y ago
Lots and lots of wire, yes, with each one cut to a specific length so that all of each gate's input signals arrive at the same time. That's why the backplane looks like a mess of wires hanging down due to seemingly being way too long.
- dragontamer 3y ago
  Note that modern RAM has length matched traces. Take a look at all the PCB traces near RAM and CPU. You can see them 'squiggle' looking for matching-space at either end of the RAM/CPU connection. PCBs make things like consistent length matching easier. All circuit boards have near identical lengths, controlled impedances and other features that support ... Well... Effectively 6-billion baudrates for DDR5. 6000Mhz DDR5 with 64-bits per half-clock (3000Mhz clock so 6000 transfers per second) has a bit every 5 centimeters or so.
whizzter 3y ago
And that kinda makes it unfair to the Raspberry, maybe not the RPI1 but I'm pretty sure that the RPi4 (rated at 78x the Cray) running code in compute-mode would thrash the Cray 1 even harder (yes, not entirely comparable but since you probably didn't get full throughput on the Cray with regular C code then using the GPU on the RPi should be fair game).
peterfirefly 3y ago
> SIMD vector instructions Err... That term is used to describe modern vector instructions that are NOT vector instructions in the classical Cray-sense. Modern CPUs use wide registers that can be regarded as vectors of 2/4/8/... values. Cray used memory-to-memory variable-length vectors. I'm not saying that "SIMD vector instructions" is an incorrect description of what the Cray machines did, I'm saying that the term usually means something else today.
heelix 3y ago
The fluorinert coolant was really neat stuff too. Inert, so you could submerge electronics in it to cool them. I was able to find recycled coolant and used that to do the liquid cooled build for my dual celeron system where coolant flowed over the board/cpu. Knowing what I do now... I should have been far less cavalier with the stuff.

msla 3y ago

> Also, fun fact, it didn't have a CPU. It used all discrete logic chips, and was wired by hand, That's how CPUs were built back then. What it didn't have was a single-chip CPU, or a microprocessor. Next up: "The Model T Ford didn't have an engine, it had this gasoline-burning device to provide motive power."

drfuchs 3y ago

Lots and lots of wire, yes, with each one cut to a specific length so that all of each gate's input signals arrive at the same time. That's why the backplane looks like a mess of wires hanging down due to seemingly being way too long.

dragontamer 3y ago
Note that modern RAM has length matched traces. Take a look at all the PCB traces near RAM and CPU. You can see them 'squiggle' looking for matching-space at either end of the RAM/CPU connection. PCBs make things like consistent length matching easier. All circuit boards have near identical lengths, controlled impedances and other features that support ... Well... Effectively 6-billion baudrates for DDR5. 6000Mhz DDR5 with 64-bits per half-clock (3000Mhz clock so 6000 transfers per second) has a bit every 5 centimeters or so.

whizzter 3y ago

And that kinda makes it unfair to the Raspberry, maybe not the RPI1 but I'm pretty sure that the RPi4 (rated at 78x the Cray) running code in compute-mode would thrash the Cray 1 even harder (yes, not entirely comparable but since you probably didn't get full throughput on the Cray with regular C code then using the GPU on the RPi should be fair game).

peterfirefly 3y ago

> SIMD vector instructions Err... That term is used to describe modern vector instructions that are NOT vector instructions in the classical Cray-sense. Modern CPUs use wide registers that can be regarded as vectors of 2/4/8/... values. Cray used memory-to-memory variable-length vectors. I'm not saying that "SIMD vector instructions" is an incorrect description of what the Cray machines did, I'm saying that the term usually means something else today.

heelix 3y ago

The fluorinert coolant was really neat stuff too. Inert, so you could submerge electronics in it to cool them. I was able to find recycled coolant and used that to do the liquid cooled build for my dual celeron system where coolant flowed over the board/cpu. Knowing what I do now... I should have been far less cavalier with the stuff.