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Comment by Froedlich

1 day ago

A friend works for an airline as a flight simulator tech. Their entire software stack, including the compiler and OS, is FAA-certified.

Then their ancient Honeywell(?) mainframes reached end-of-life they scouted for compatible hardware, of which there was none. The cost of certifying new software, plus the time involved, was astronomical. So, after consulting with the FAA, they paid a hardware company to clone the ancient mainframes in modern silicon. The FAA signed off on it, and they had all-new computers - much smaller than the originals - running the old stack.

23 comments

Froedlich

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zx8080  1 day ago

It's _very_ hard to believe some company to simply "clone the mainframe" into chip. Mind sharing any link to this effort?

  • vincent-manis  1 day ago

    When Xerox established PARC, they asked the assembled scientists what computer they wanted. The majority view was a DEC PDP-10 KA10, with the BBN memory management unit that let it run Tenex (the ancestor of DEC TOPS-20). Xerox couldn't really buy a competitor's mainframe, so they built MAXC (maximum access computer), which was a complete emulation of the Tenex machines.

    • fsckboy  11 hours ago

      >MAXC (maximum access computer), which was a complete emulation of the Tenex machines.

      Compuserve also had a software dependency on the PDP-10 and Decsystem 20, and when those machines were no longer available they bought a company making clones so they could continue to manufacture them for themselves. The company they bought, Microsolutions, was Mark Cuban's first startup.

      making clones of mainframes (IBM's) had been a big area of intellectual property litigation, but also facing monopolization investigations, IBM had to allow them. They were referred to as "plug compatibles".

  • jasomill  4 hours ago

    IBM released the PC XT/370[1], built around a pair of 68000s and an 8087 with custom microcode to emulate System/370 instructions, in 1983.

    It's not hard to imagine a similar system fabricated around an open or licensed processor core today being well within the budget of a major airline today.

    Software emulation would no doubt be less expensive, but there could have been regulatory reasons for building plug-compatible hardware.

    [1] https://en.wikipedia.org/wiki/PC-based_IBM_mainframe-compati...

  • flyinghamster  14 hours ago

    It could be an FPGA. Given enough gates, and the know-how to program them, you can make an FPGA emulate anything. Speed and efficiency could be better or worse, but if you're targeting old hardware, better is likely.

  • mitxela  17 hours ago

    Custom chips aren't as expensive as you think. About a few million dollars for the design and a hundred thousand chips, way out of reach for a hobbyist, but accessible to large enough companies. Just because it's opaque to us software people doesn't mean it's not a real industry you can buy things from.

    • realo  15 hours ago

      And all that expensive engineering is still less costly AND faster (!!) than a new software certification.

      Cannot refrain myself from asking why ...

      4 replies →

  • theodric  18 hours ago

    I mean...there's some precedent. The XKL TOAD ("Ten On A Desk") implements the PDP-10 instruction set, and will happily run TOPS-10/TOPS-20. LCM had one doing just that.

    https://www.computerhistory.org/collections/catalog/10277383... https://www.twenex.org/?network

  • znpy  19 hours ago

    Meh, old architectures are relatively simple and you can get 95% of those via fpga softcores (some freely available, some paid) and run them on fpga. The rest can be implemented by a proper ee team.

betaby  1 day ago

That's interesting. That means there are fewer checks for hardware than software?

  • soulofmischief  1 day ago

    Hardware is more amenable to static analysis than running programs which may receive an arbitrary number of inputs and express an arbitrary number of possible intermediate states.

    I am interested in how firmware is treated, since perhaps in the case of these old machines it's small enough to be analyzable or at least cloned bit-for-bit.

fsckboy  12 hours ago

>Then their ancient Honeywell(?) mainframes...

https://en.wikipedia.org/wiki/GE-600_series from the 36-bit era which turned out to be a sweet-spot for Lisp; also "famous" for running Multics (old joke flipped: "which was many of whatever unix is one of")

GE sold it's division to Honeywell, and from there to Group Bull (French) and then to NEC (Japan)