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Can you expand on that? Was this a property of C compilers or other languages on IBM mainframes? I get that it's tongue in cheek, but it would probably be eve

by wffurr 5y ago

Can you expand on that? Was this a property of C compilers or other languages on IBM mainframes? I get that it's tongue in cheek, but it would probably be even funnier / ironic if I had more context to understand it. It's the same spirit as languages adopting functional programming techniques aka rediscovering Lisp.

formerly_proven 5y ago
AS/400 had a machine-independent binary format which was translated ahead of execution by the system's specific compiler into machine code, and all applications ran in the same address space with zero memory protection because the code generated by the compiler ensured isolation.
- ksec 5y ago
  Oh wow. So again, we have come a full circle?
- 1_player 5y ago
  Incredible, I always thought that was an idea worth exploring. AOT compilation and not paying the cost of context and MMU switch would unlock incredible performance boosts, even on modern processors. I didn't know AS/400 did that already. IIRC Microsoft explored something similar with their research OS Singularity.
- tambourine_man 5y ago
  >because the code generated by the compiler ensured isolation That's fascinating. How does it do so? I thought it only separated the address space into user space and OS space.
  - coliveira 5y ago
    I imagine that this was possible because the compiler had help from the AS400 architecture. In other words, doing this for a complex architecture like i64 would be much more difficult.
    - pjmlp 5y ago
      Modern AS/400 runs on PowerPC, the hardware is completly different from the early 1980's models.
      - tambourine_man 5y ago
        I understand the ISA abstraction. That’s pretty common. I’m interested in how the compiler ensures process isolation.
- dmw_ng 5y ago
  From the same era: https://en.wikipedia.org/wiki/Architecture_Neutral_Distribution_Format https://en.wikipedia.org/wiki/Architecture_Neutral_Distribut...
- pjmlp 5y ago
  No need for past tense, AS/400 still exists, just got the name changed to IBM i.

by wffurr 5y ago

formerly_proven 5y ago

AS/400 had a machine-independent binary format which was translated ahead of execution by the system's specific compiler into machine code, and all applications ran in the same address space with zero memory protection because the code generated by the compiler ensured isolation.

ksec 5y ago
Oh wow. So again, we have come a full circle?
1_player 5y ago
Incredible, I always thought that was an idea worth exploring. AOT compilation and not paying the cost of context and MMU switch would unlock incredible performance boosts, even on modern processors. I didn't know AS/400 did that already. IIRC Microsoft explored something similar with their research OS Singularity.
tambourine_man 5y ago
>because the code generated by the compiler ensured isolation That's fascinating. How does it do so? I thought it only separated the address space into user space and OS space.
- coliveira 5y ago
  I imagine that this was possible because the compiler had help from the AS400 architecture. In other words, doing this for a complex architecture like i64 would be much more difficult.
  - pjmlp 5y ago
    Modern AS/400 runs on PowerPC, the hardware is completly different from the early 1980's models.
    - tambourine_man 5y ago
      I understand the ISA abstraction. That’s pretty common. I’m interested in how the compiler ensures process isolation.
dmw_ng 5y ago
From the same era: https://en.wikipedia.org/wiki/Architecture_Neutral_Distribution_Format https://en.wikipedia.org/wiki/Architecture_Neutral_Distribut...
pjmlp 5y ago
No need for past tense, AS/400 still exists, just got the name changed to IBM i.