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Do we have any hope for garbage collecting CPUs 40 years later or are they a doomed venture? > In 1975, Intel's next big plan was the 8800 processor designed t

Do we have any hope for garbage collecting CPUs 40 years later or are they a doomed venture? > In 1975, Intel's next big plan was the 8800 processor designed to be Intel's chief architecture for the 1980s. This processor was called a "micromainframe" because of its planned high performance. It had an entirely new instruction set designed for high-level languages such as Ada, and supported object-oriented programming and garbage collection at the hardware level.

nullc 6y ago
I'd much rather have a security-oriented processor with tagged bounds checked pointers... such a facility could also make garbage collecting more efficient, but what it could do for security would be wonderful.
- josephcsible 6y ago
  Isn't that basically what the stillborn Intel MPX was?
  - nullc 6y ago
    MPX was pretty limited, but yes-- it moved in that direction. https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ is more what I was thinking
- kens 6y ago
  The 8800 (iAPX 432) provided bounds checking too. Every object reference wasn't a pointer but an "Access Descriptor" that included permissions. So you couldn't access anything out of bounds. I should emphasize that this isn't like a JVM, but was implemented at the machine instruction level. It's hard to understand how strange and radical this processor was. https://en.wikipedia.org/wiki/Intel_iAPX_432#Object-oriented_memory_and_capabilities https://en.wikipedia.org/wiki/Intel_iAPX_432#Object-oriented...
  - Icathian 6y ago
    Every time I hear about abandoned "improved" tech like this, I always wonder why the idea was shelved. The link kinda handwaves it away. Any good resources on why the idea didn't take off?
    - atombender 6y ago
      It probably didn't help performance. But there's some good news: ARM has added pretty much the same thing, called MTE (Memory Tagging Extension) [1], which uses the upper 4 bits of memory addresses as a region identifier. [1] https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/enhancing-memory-safety https://community.arm.com/developer/ip-products/processors/b...
    - pwg 6y ago
      You'd probably have to find an Intel insider to know the real truth. But the most likely possibility is that the plan was too grand for the time (note, this was 197x to ~ 1984ish, the IBM PC with its 8088 had only been on the market about three or so years) and therefore much too expensive for any market to bear. Additionally, the iAPX432 was being worked upon during the same time that the IBM PC suddenly brought the x86 chips to significant popularity. Combine the concepts of pouring money into an arch. that was too big and grandiose for the integration tech. at the time, with a sudden influx of profit from the x86 chip line, and it seems that a likely reason was simply to devote resources to the chip line that was suddenly producing those same resources. The Wikipedia page (https://en.wikipedia.org/wiki/IAPX432 https://en.wikipedia.org/wiki/IAPX432) also says this about the '432: "Using the semiconductor technology of its day, Intel's engineers weren't able to translate the design into a very efficient first implementation. Along with the lack of optimization in a premature Ada compiler, this contributed to rather slow but expensive computer systems, performing typical benchmarks at roughly 1/4 the speed of the new 80286 chip at the same clock frequency (in early 1982).[7] This initial performance gap to the rather low-profile and low-priced 8086 line was probably the main reason why Intel's plan to replace the latter (later known as x86) with the iAPX 432 failed. Although engineers saw ways to improve a next generation design, the iAPX 432 capability architecture had now started to be regarded more as an implementation overhead rather than as the simplifying support it was intended to be."
- atombender 6y ago
  This has been added to ARM: https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/enhancing-memory-safety https://community.arm.com/developer/ip-products/processors/b...
- saagarjha 6y ago
  As another commenter notes, ARM is getting MTE very soon, and ARM Morello (CHERI-inspired) prototype boards might be made available soon as well.

nullc 6y ago

I'd much rather have a security-oriented processor with tagged bounds checked pointers... such a facility could also make garbage collecting more efficient, but what it could do for security would be wonderful.

josephcsible 6y ago
Isn't that basically what the stillborn Intel MPX was?
- nullc 6y ago
  MPX was pretty limited, but yes-- it moved in that direction. https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ is more what I was thinking
kens 6y ago
The 8800 (iAPX 432) provided bounds checking too. Every object reference wasn't a pointer but an "Access Descriptor" that included permissions. So you couldn't access anything out of bounds. I should emphasize that this isn't like a JVM, but was implemented at the machine instruction level. It's hard to understand how strange and radical this processor was. https://en.wikipedia.org/wiki/Intel_iAPX_432#Object-oriented_memory_and_capabilities https://en.wikipedia.org/wiki/Intel_iAPX_432#Object-oriented...
- Icathian 6y ago
  Every time I hear about abandoned "improved" tech like this, I always wonder why the idea was shelved. The link kinda handwaves it away. Any good resources on why the idea didn't take off?
  - atombender 6y ago
    It probably didn't help performance. But there's some good news: ARM has added pretty much the same thing, called MTE (Memory Tagging Extension) [1], which uses the upper 4 bits of memory addresses as a region identifier. [1] https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/enhancing-memory-safety https://community.arm.com/developer/ip-products/processors/b...
  - pwg 6y ago
    You'd probably have to find an Intel insider to know the real truth. But the most likely possibility is that the plan was too grand for the time (note, this was 197x to ~ 1984ish, the IBM PC with its 8088 had only been on the market about three or so years) and therefore much too expensive for any market to bear. Additionally, the iAPX432 was being worked upon during the same time that the IBM PC suddenly brought the x86 chips to significant popularity. Combine the concepts of pouring money into an arch. that was too big and grandiose for the integration tech. at the time, with a sudden influx of profit from the x86 chip line, and it seems that a likely reason was simply to devote resources to the chip line that was suddenly producing those same resources. The Wikipedia page (https://en.wikipedia.org/wiki/IAPX432 https://en.wikipedia.org/wiki/IAPX432) also says this about the '432: "Using the semiconductor technology of its day, Intel's engineers weren't able to translate the design into a very efficient first implementation. Along with the lack of optimization in a premature Ada compiler, this contributed to rather slow but expensive computer systems, performing typical benchmarks at roughly 1/4 the speed of the new 80286 chip at the same clock frequency (in early 1982).[7] This initial performance gap to the rather low-profile and low-priced 8086 line was probably the main reason why Intel's plan to replace the latter (later known as x86) with the iAPX 432 failed. Although engineers saw ways to improve a next generation design, the iAPX 432 capability architecture had now started to be regarded more as an implementation overhead rather than as the simplifying support it was intended to be."
atombender 6y ago
This has been added to ARM: https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/enhancing-memory-safety https://community.arm.com/developer/ip-products/processors/b...
saagarjha 6y ago
As another commenter notes, ARM is getting MTE very soon, and ARM Morello (CHERI-inspired) prototype boards might be made available soon as well.