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Itanium was not stupid. Some genuine effort behind it could have changed this whole story.

markhahn 2y ago
I'm curious why you think there was not effort behind ia64. I still think ia64 was sunk by the let-the-compiler-do-it tarpit. There were ambivalent aspects such as, at the time, questions of power or chip area. But things like memory latency are just not predictable enough to do strictly in-order pipelines. OoO won.
- pjmlp 2y ago
  Not the OP, but share a similar point of view. Had AMD not been around with AMD64, the industry would have had to get it working no matter what, HP and Microsoft were already on the Itanium train, and if production of x86 got slowly replaced by Itanium that was it, Windows and HP-UX would drag the ecosystems into it, and eventually the remaining issues would be sorted out.
  - rwmj 2y ago
    Wouldn't the world have jumped to Alpha instead? If you're going to switch the entire architecture, might as well switch to one which is sane.
    - pjmlp 2y ago
      Windows on Alpha didn't went far, so I guess no. UNIX systems, I also doubt, as we were still in the days each vendor had their own CPUs.
    - ghaff 2y ago
      No. HP was behind Itanium. In fact, it was basically their idea in the first place. I'm still not entirely sure why Intel went along although I suspect at least some of it was getting away from various x86 cross-licensing agreements.
    - wmf 2y ago
      Intel bought Alpha and killed it to eliminate the competition.
      - ghaff 2y ago
        HP bought DEC by way of Compaq. Some DEC Alpha assets ended up with Intel (e.g. Hudson MA). But your statement doesn't make sense in general.
  - twoodfin 2y ago
    My issue with this alternative history is Intel’s consumer roadmap for Itanium, or rather its complete lack of one. AFAICT, they expected Itanium to own the high end server/HPC market, while 32-bit x86 would continue supporting PC’s for another decade. That seems remarkably short-sighted in retrospect.
  - ghaff 2y ago
    I'm inclined to agree. Intel would have been loathe to go the 64-bit x86 route on their own. But a somewhat resurgent AMD pretty much forced their hand given the sorry state of Itanium development. Absent AMD, I'm pretty sure they'd have found a path to a "good enough" Itanium to sell successfully. For what it's worth, I followed Itanium as an IT industry analyst and wrote a short book recently on the topic. https://s3.amazonaws.com/bitmasons.com/docs/Lessons+from+the+Itanic-ebook.pdf https://s3.amazonaws.com/bitmasons.com/docs/Lessons+from+the...
    - MBCook 2y ago
      Right. Even if Itanium worked better and was released to consumers AMD might have done the same thing and still won.
- Tteriffic 2y ago
  The compilers were fine, even if not producing maximally optimized code. Intel’s decision to add x86 compatibility circuitry to the die was probably the fatal one, it slowed everything down; made for terrible comparisons with existing x86 performance and generally signalled a lack of confidence. Something like Rosetta was out of the question, but they could have just had better transitioning tools for those code bases that couldn’t be recompiled easily.

I'm curious why you think there was not effort behind ia64. I still think ia64 was sunk by the let-the-compiler-do-it tarpit. There were ambivalent aspects such as, at the time, questions of power or chip area. But things like memory latency are just not predictable enough to do strictly in-order pipelines. OoO won.

pjmlp 2y ago
Not the OP, but share a similar point of view. Had AMD not been around with AMD64, the industry would have had to get it working no matter what, HP and Microsoft were already on the Itanium train, and if production of x86 got slowly replaced by Itanium that was it, Windows and HP-UX would drag the ecosystems into it, and eventually the remaining issues would be sorted out.
- rwmj 2y ago
  Wouldn't the world have jumped to Alpha instead? If you're going to switch the entire architecture, might as well switch to one which is sane.
  - pjmlp 2y ago
    Windows on Alpha didn't went far, so I guess no. UNIX systems, I also doubt, as we were still in the days each vendor had their own CPUs.
  - ghaff 2y ago
    No. HP was behind Itanium. In fact, it was basically their idea in the first place. I'm still not entirely sure why Intel went along although I suspect at least some of it was getting away from various x86 cross-licensing agreements.
  - wmf 2y ago
    Intel bought Alpha and killed it to eliminate the competition.
    - ghaff 2y ago
      HP bought DEC by way of Compaq. Some DEC Alpha assets ended up with Intel (e.g. Hudson MA). But your statement doesn't make sense in general.
- twoodfin 2y ago
  My issue with this alternative history is Intel’s consumer roadmap for Itanium, or rather its complete lack of one. AFAICT, they expected Itanium to own the high end server/HPC market, while 32-bit x86 would continue supporting PC’s for another decade. That seems remarkably short-sighted in retrospect.
- ghaff 2y ago
  I'm inclined to agree. Intel would have been loathe to go the 64-bit x86 route on their own. But a somewhat resurgent AMD pretty much forced their hand given the sorry state of Itanium development. Absent AMD, I'm pretty sure they'd have found a path to a "good enough" Itanium to sell successfully. For what it's worth, I followed Itanium as an IT industry analyst and wrote a short book recently on the topic. https://s3.amazonaws.com/bitmasons.com/docs/Lessons+from+the+Itanic-ebook.pdf https://s3.amazonaws.com/bitmasons.com/docs/Lessons+from+the...
  - MBCook 2y ago
    Right. Even if Itanium worked better and was released to consumers AMD might have done the same thing and still won.
Tteriffic 2y ago
The compilers were fine, even if not producing maximally optimized code. Intel’s decision to add x86 compatibility circuitry to the die was probably the fatal one, it slowed everything down; made for terrible comparisons with existing x86 performance and generally signalled a lack of confidence. Something like Rosetta was out of the question, but they could have just had better transitioning tools for those code bases that couldn’t be recompiled easily.