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One of the 6600 designers said: > I suppose the picture of computing is of a topsy-turvy growth obeying laws of a commercial "natural" selection. This could be

One of the 6600 designers said: > I suppose the picture of computing is of a topsy-turvy growth obeying laws of a commercial "natural" selection. This could be entirely accurate considering how fast it has grown. Things started out in a scholarly vein, but the rush of commerce hasn't allowed much time to think where we're going. — JET I was amazed to read some of what he wrote at the time about the 6600 design and consider how qualitatively modern it sounds (if one is willing to add zeros and change units where quantitatively needed).

Animats 3y ago
The CDC 6600 was really a rather simple machine; it just had multiple copies of some units. The CRAY-I was even simpler, but had 64 copies of some units. Both were designed by small teams and had simple instruction sets. The other extreme was the Pentium Pro, the first superscalar x86 CPU. I went to the talk at Stanford where the lead designer described the architecture. That was the most insanely complicated CPU built up to that time. People were thinking RISC was the future, because nobody could possibly get something as messy as x86 to go much faster by architectural means. But Intel brought it off. One of the speaker's graphs showed the number of engineers involved over time. That peaked around 3000 people. Just getting that many people to work together to design one tightly-coordinated thing was an impressive achievement.
- rbanffy 3y ago
  > That peaked around 3000 people. The number directly from the Pentium team was 3000.0000000001 people at the highest point.
- _a_a_a_ 3y ago
  > The CDC 6600 was really a rather simple machine; ... The CRAY-I was even simpler Pretty bold claim, can you explain why you believe this is so? > But Intel brought it off. Not by buying up and killing the Alpha AXP, oh no.
  - B1FF_PSUVM 3y ago
    The DEC Alpha was the swan song of Digital Equipment Corporation, which was bought by Compaq (a PC manufacturer that peaked in the 1990s), which was bought by HP. Intel had little to do with it.
    - pdw 3y ago
      I don't know the details, but from Wikipedia: "In May 1997, DEC sued Intel for allegedly infringing on its Alpha patents in designing the original Pentium, Pentium Pro, and Pentium II chips. As part of a settlement, much of DEC's chip design and fabrication business was sold to Intel."
      - p_l 3y ago
        In the 1990s, especially latter half, Digital's leadership went on divestment-oriented business management, and managed to ultimately divest the company of its future.
        KerrAvon 3y ago
        In hindsight, weren't they basically finished by 1989? We'd be living in a different world if they'd put all the money from the VAX 9000 into RISC CPUs instead.
        convolvatron 3y ago
        there was a whole line of mips decstations. I think that part of the market was already saturated for them.
        p_l 3y ago
        Not really - Alpha was quite successful. My personal suspicion is that if instead of chasing quick returns through divestment that had worked on keeping a portfolio of products that drove sales for each other (for example, Rdb which to my understanding was fairly successful in some areas) the results might have been different. There's reason why so many places kept to Digital gear even after Compaq mishandling, then the Itanium and HP days, and not all of those were customers that had problematic rewrites blocking any migration (like customers dependant on VMS).
- clamchowder 3y ago
  The original Pentium was the first superscalar x86 CPU. Superscalar just means you can execute faster than scalar (one instruction at a time), and the P5 could theoretically sustain 2 IPC. Of course it was in-order so cache misses would likely prevent you from getting there. The Pentium Pro was Intel's first out-of-order design. It's also superscalar. StackOverflow has a really funny post by Andy Glew, who worked on the Pentium Pro, noting that a scalar out-of-order machine could make sense in some corner cases. (https://stackoverflow.com/questions/10074831/what-is-general-difference-between-superscalar-and-out-of-order-ooo-execution https://stackoverflow.com/questions/10074831/what-is-general...)
  - dbcurtis 3y ago
    If you were an instruction pairing whiz, you could get pretty close to 2 IPC on the Pentium I for certain kernels. The thing that Seymour had going for him at CDC is that he didn't bother with synchronous exceptions. On x86 (I worked on a late 486, Pentium I, Pentium II and Itanium II) you absolutely must have synchronous exceptions for backward compatibility. Debugging an exception on 6600 was a hair-tearing exercise, because the PC point somewhere near, not at, the instruction that raised, and there may be a swiss-cheese window of instructions that did not complete somewhere before that. Loads of fun for one and all. (I used 6600/7600's while working on Cyber 203/205 at CDC).
- allenrb 3y ago
  I think that’s not quite correct re: the Cray 1 having 64 copies of certain units. True, the vector registers did have 64 entries but the vector functional units were pipelined. They could return a result each cycle (once past the initial latency) but did not return 64 results simultaneously.

Animats 3y ago

The CDC 6600 was really a rather simple machine; it just had multiple copies of some units. The CRAY-I was even simpler, but had 64 copies of some units. Both were designed by small teams and had simple instruction sets. The other extreme was the Pentium Pro, the first superscalar x86 CPU. I went to the talk at Stanford where the lead designer described the architecture. That was the most insanely complicated CPU built up to that time. People were thinking RISC was the future, because nobody could possibly get something as messy as x86 to go much faster by architectural means. But Intel brought it off. One of the speaker's graphs showed the number of engineers involved over time. That peaked around 3000 people. Just getting that many people to work together to design one tightly-coordinated thing was an impressive achievement.

rbanffy 3y ago
> That peaked around 3000 people. The number directly from the Pentium team was 3000.0000000001 people at the highest point.
_a_a_a_ 3y ago
> The CDC 6600 was really a rather simple machine; ... The CRAY-I was even simpler Pretty bold claim, can you explain why you believe this is so? > But Intel brought it off. Not by buying up and killing the Alpha AXP, oh no.
- B1FF_PSUVM 3y ago
  The DEC Alpha was the swan song of Digital Equipment Corporation, which was bought by Compaq (a PC manufacturer that peaked in the 1990s), which was bought by HP. Intel had little to do with it.
  - pdw 3y ago
    I don't know the details, but from Wikipedia: "In May 1997, DEC sued Intel for allegedly infringing on its Alpha patents in designing the original Pentium, Pentium Pro, and Pentium II chips. As part of a settlement, much of DEC's chip design and fabrication business was sold to Intel."
    - p_l 3y ago
      In the 1990s, especially latter half, Digital's leadership went on divestment-oriented business management, and managed to ultimately divest the company of its future.
      - KerrAvon 3y ago
        In hindsight, weren't they basically finished by 1989? We'd be living in a different world if they'd put all the money from the VAX 9000 into RISC CPUs instead.
        convolvatron 3y ago
        there was a whole line of mips decstations. I think that part of the market was already saturated for them.
        p_l 3y ago
        Not really - Alpha was quite successful. My personal suspicion is that if instead of chasing quick returns through divestment that had worked on keeping a portfolio of products that drove sales for each other (for example, Rdb which to my understanding was fairly successful in some areas) the results might have been different. There's reason why so many places kept to Digital gear even after Compaq mishandling, then the Itanium and HP days, and not all of those were customers that had problematic rewrites blocking any migration (like customers dependant on VMS).
clamchowder 3y ago
The original Pentium was the first superscalar x86 CPU. Superscalar just means you can execute faster than scalar (one instruction at a time), and the P5 could theoretically sustain 2 IPC. Of course it was in-order so cache misses would likely prevent you from getting there. The Pentium Pro was Intel's first out-of-order design. It's also superscalar. StackOverflow has a really funny post by Andy Glew, who worked on the Pentium Pro, noting that a scalar out-of-order machine could make sense in some corner cases. (https://stackoverflow.com/questions/10074831/what-is-general-difference-between-superscalar-and-out-of-order-ooo-execution https://stackoverflow.com/questions/10074831/what-is-general...)
- dbcurtis 3y ago
  If you were an instruction pairing whiz, you could get pretty close to 2 IPC on the Pentium I for certain kernels. The thing that Seymour had going for him at CDC is that he didn't bother with synchronous exceptions. On x86 (I worked on a late 486, Pentium I, Pentium II and Itanium II) you absolutely must have synchronous exceptions for backward compatibility. Debugging an exception on 6600 was a hair-tearing exercise, because the PC point somewhere near, not at, the instruction that raised, and there may be a swiss-cheese window of instructions that did not complete somewhere before that. Loads of fun for one and all. (I used 6600/7600's while working on Cyber 203/205 at CDC).
allenrb 3y ago
I think that’s not quite correct re: the Cray 1 having 64 copies of certain units. True, the vector registers did have 64 entries but the vector functional units were pipelined. They could return a result each cycle (once past the initial latency) but did not return 64 results simultaneously.