4 ms·

Interesting how much early processor history was driven by Intel project delays.

Tuna-Fish 7y ago
IMHO the story of the iAPX432 really is the whole industry in microcosm. Intel hires the best of the best, the true cream of the crop to design them an ISA that is meant to crystallize everything that is known about ISA design into a single completely new design that discards all the broken crap of yesterday and will be futureproof for decades if not forever, and a chip to implement it. Everything is going to be great forever, but it turns out it's a bit hard to get done, so they just have the B-team whip up something quick to sell in the meantime. This something was the 8086, which gets adopted into increasingly successful products, but no matter, the new shiny thing is going to displace all of that when it finally ships. Then it does, and it actually has a hard time competing in performance with the much older stopgap product. It turns out that the team of superstars they hired was very theoretical, and built an ISA that was a dream to program against, but did not really understand what it took to build something that was going to be fast when implemented in hardware. (Also, the system was meant to be used mainly with high-level languages, and the compilers really were not there yet.) Being more expensive, much slower than the competition and with 0 market penetration, the iAPX 432 was dead on arrival in the market. Luckily, the B-team had been busy working up on another extension of the stop-gap product, the 80286, which is again a runaway success, and only partially because of backwards compatibility with the existing x86 ecosystem. It was also quite fast for it's time.
- pjmlp 7y ago
  Intel history is full of such missteps. Last one was dropping MPX, while everyone else is making memory tagging compulsory as means to tame C and C++ code.
- JoeAltmaier 7y ago
  I recall the iAPX432 came out years later than the 8086, was a 'capabilities machine' and took 500 memory cycles to execute "JMP ." e.g. jump to self, potentially the simplest possible operation.
- Tteriffic 7y ago
  Sounds just like the Itanium/amd64 story.

IMHO the story of the iAPX432 really is the whole industry in microcosm. Intel hires the best of the best, the true cream of the crop to design them an ISA that is meant to crystallize everything that is known about ISA design into a single completely new design that discards all the broken crap of yesterday and will be futureproof for decades if not forever, and a chip to implement it. Everything is going to be great forever, but it turns out it's a bit hard to get done, so they just have the B-team whip up something quick to sell in the meantime. This something was the 8086, which gets adopted into increasingly successful products, but no matter, the new shiny thing is going to displace all of that when it finally ships. Then it does, and it actually has a hard time competing in performance with the much older stopgap product. It turns out that the team of superstars they hired was very theoretical, and built an ISA that was a dream to program against, but did not really understand what it took to build something that was going to be fast when implemented in hardware. (Also, the system was meant to be used mainly with high-level languages, and the compilers really were not there yet.) Being more expensive, much slower than the competition and with 0 market penetration, the iAPX 432 was dead on arrival in the market. Luckily, the B-team had been busy working up on another extension of the stop-gap product, the 80286, which is again a runaway success, and only partially because of backwards compatibility with the existing x86 ecosystem. It was also quite fast for it's time.

pjmlp 7y ago
Intel history is full of such missteps. Last one was dropping MPX, while everyone else is making memory tagging compulsory as means to tame C and C++ code.
JoeAltmaier 7y ago
I recall the iAPX432 came out years later than the 8086, was a 'capabilities machine' and took 500 memory cycles to execute "JMP ." e.g. jump to self, potentially the simplest possible operation.
Tteriffic 7y ago
Sounds just like the Itanium/amd64 story.