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  • Raqia - Monday, August 17, 2020 - link

    Amazing that this instruction set lives on, because: COBOL.
  • Dolda2000 - Monday, August 17, 2020 - link

    I'll just say that I read up on the System/360 base instruction set a while ago, and it was actually a lot more elegant than I expected it to be. There are even aspects of it that are surprisingly RISC-like for being so early.
  • abufrejoval - Thursday, August 20, 2020 - link

    No, you can run Cobol on anything, just need a compiler. The instruction set lives on because of binary compatibility to 360 and beyond.
  • frbeckenbauer - Monday, August 17, 2020 - link

    Who fabs these chips? IBM is fabless these days, right?
  • tipoo - Monday, August 17, 2020 - link

    Samsung
  • jeremyshaw - Monday, August 17, 2020 - link

    Well, this one is probably GlobalFoundries 14nm (basically Samsung again) or 14 FD-SOI at GloFo.
  • melgross - Tuesday, August 18, 2020 - link

    That’s basically saying that you don’t know, because those are pretty much the only ones who can do it, unless IBM is still running a small fab just for this.
  • eastcoast_pete - Monday, August 17, 2020 - link

    Last year, someone asked me which programming language they should study, and I said: COBOL. And I wasn't joking. However, little did I know that we would need COBOL experts so desperately a few months later; in many states here in the US, unemployment benefit applications were delayed by weeks after Covid hit, because the programs processing them were all in COBOL, and it's really hard to scale out if most of your COBOL programmers are long retired or dead. These new mainframes also exist because COBOL lives on.
  • RSAUser - Tuesday, August 18, 2020 - link

    Over the next few years I think a lot of COBOL systems are going to start being rewritten.
    While there were so many COBOL programmers left, it definitely was not worth rewriting such systems, and COBOL is still amazing for batch processing, but as banking will start moving more and more to "immediate" processing, COBOLs strengths will start decreasing.

    I am expecting COBOL to evolve into something like a Golang COBOL hybrid.
  • IanWorthington - Monday, August 17, 2020 - link

    > 02:19PM EDT - Core is called millicode ?

    No. Millicode implements complex subroutine instructions.

    >5.2GHz:
    iirc, it slows down to 5GHz under certain circumstances.

    And don't forget, i/o is handled in separate "channel" processors. Linuxy stuff can be spun off to separate ZIIP processors.
  • Ian Cutress - Monday, August 17, 2020 - link

    They eventually said 5.2 GHz base in the Q&A
  • ikjadoon - Monday, August 17, 2020 - link

    >The goal of these cores is to be recoverable, even when blasted with high-energy proton beams

    Well, I personally now feel underprepared for any incoming high-energy proton beams.
  • Mdarrish - Monday, August 17, 2020 - link

    They or similar high energy radiation come in all the time - cosmic rays switch the state of gates in processors. The smaller the transistors, the easier it is to switch the state. Modern CPUs have redundant circuits to ‘vote’ on results when that happens.
  • octavus - Monday, August 17, 2020 - link

    Too bad that 940GB L4 cache chip can't be an option for X86 systems.
  • Lord of the Bored - Monday, August 17, 2020 - link

    "02:05PM EDT - Programs built in 1964 on IBM mainframes still work today"

    I am torn. On the one hand, I strongly believe that sort of backwards-compatibility is something to be applauded.
    On the other hand, the surrounding context makes me concerned that they know this because some ancient program that hasn't been maintained in fifty years is a critical part of everyday financial transactions.
  • Mdarrish - Monday, August 17, 2020 - link

    They were updated for Y2K, so only 20 years. Seriously, there are usually updates along the way. The point is that critical business systems don’t have to be rewritten or need emulators.
  • Zizy - Tuesday, August 18, 2020 - link

    If it works, why break it?
    While I doubt there is any meaningfully large piece of software from that era still in use, some core algorithms likely have been written back then and are still used today completely unmodified in over 50 years.
  • quadibloc - Tuesday, August 18, 2020 - link

    The z15 has a very deep pipeline. So it's not surprising that it can have a 5.2 GHz clock. It's like a Pentium 4 (or even a Bulldozer); and it's kept cool by a fancy water-cooling system. So IBM hasn't worked miracles, it's just attained 5.2 GHz in ways that Intel and AMD reject for good reason.
  • melgross - Tuesday, August 18, 2020 - link

    AMD sand Intel can’t do this because this is a very large system. The cost to do it likely costs more than the totality of most server rooms.
  • Dolda2000 - Wednesday, August 19, 2020 - link

    To be fair though, a lot of the pipeline depth seems to be contributed by the retire/commit side of things, with all the extra stages for checkpointing and verification, which shouldn't leave any effect on branch mispredict penalties.

    Granted, the front-end pipeline isn't exactly short, but it doesn't look completely out of line compared to Intel designs. If anything, it surprises me a bit that they haven't implemented a micro-op cache to bypass all those myriad of steps they seem to have for decoding. It looks like something the design would benefit quite a lot from.

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