back to article Free x86 mainframes for all! Virtual x86 mainframes, that is

Unisys's ClearPath colosso-servers may have finally moved from the weirdness of CMOS to the mundanity x86, but the servers and their operating systems still remain rather exotic and therefore not the kind of thing the curious often get to prod. But it's come to the attention of The Register's virtualisation desk that Unisys …

  1. Pascal Monett Silver badge

    Just a thought

    Would it be possible to use those VMs for secure browsing ? If they're not Windows, it should cut down measurably on the risks taken when surfing, no ?

    I like VMs, but a Windows VM is still Windows, even if it is a VM. A VM that is not Windows would be like the ocean to cross for a lemming - and I would feel that much more secure in this wild, treacherous environment.

    Of course I could also use a Linux image, I know, but for the sheer thrill of it, I'd like to imagine using an industrial compressor to crack Internet walnuts.

    1. allthecoolshortnamesweretaken

      Re: Just a thought

      Sounds intriguing. Anyone here who knows enough about UNISYS to answer this? Could the ACME SPLAFFER run in this?

      BTW, I came here to ask if anybody could tell me what a virtual UNISYS mainframe could be used for. So browsing aside, what can you actually do with this?

  2. Anonymous Coward
    Anonymous Coward

    what a virtual UNISYS mainframe could be used for

    Well, it could show that the MASM version of Kermit I worked on in 1987 actually worked.

    It's an odd feeling having my name immortalised in a USENET post older than some of my colleagues. But it's a good response if anyone asks me "what experience have you got ?". I also worked on some RFCs, but they were submitted from a group address :(

  3. x 7

    I didn't know Unisys was still alive, not heard of it for years.

    Who uses it nowadays? And what actually runs on it?

    1. Richard Steiner

      Some airlines still use OS2200 Clearpath mainframes for various things. We use them at my own place of work.

      I'm sure the MCP side of Unisys' Clearpath customer base still exists, also. That's the Burroughs A-series boxes. WFL, CANDE, and friends.

  4. Gomez Adams

    How much do I yearn to use an instruction like SNZ (store negative zero) again? :D

    And have they sorted out the TDATE$ word format issue that will blow up in their faces come 2028?

  5. allthecoolshortnamesweretaken

    I repeat my question because I'd really like to know: what could I run on that?

    My only experience with working on mainframes was Fortran77 coursework (or cursework) on a CDC Cyber about 30 years ago, never worked on anything by UNISYS.

    1. x 7

      "I repeat my question because I'd really like to know: what could I run on that?"

      and I'll echo it: can you do anything useful with them?

      1. Richard Steiner

        Define useful?

        I would rather use my own version of UEDIT for editing files than any UNIX editor I've found, and since I have the source and 20 years of knowledge with its internals, I could continue to improve it.

        Not sure how easy it would be to get text files in and out of the emulation, however.

        Other than that, it depends. Like any platform, the usefulness is largely determined by the software you can write or find. You're largely talking about text mode software, tho. I wonder which terminal emulations are available? I would want at least UTS20. UTS60 does colors natively.

        FWIW, OS2200 and MCP are each pretty different from KRONOS or NOS (the only two CDC operating systems I've used). I don't remember much about them, either, aside from using local software like MULTI on MECC systems to play CCOMBAT. :-)

    2. Michael Wojcik Silver badge

      A few years back I worked with a partner ISV that sold a Unisys mainframe emulation product. At the time they had a pretty healthy business moving people off physical Unisys systems onto emulated ones - if memory serves, the emulator ran on Windows.

      As far as I know, they're still around, and so is their market. So there's still enough of an installed base of applications running under at least one Unisys mainframe OS to support a business based on migrating applications to an emulator.

      From a high level, OS 2200 is not that different from IBM's zOS and predecessors. You have batch and online processing, with a transaction monitor, etc. So people run back-office business apps: billing, customer management, inventory management. That sort of thing.

      IIRC, the main interactive user interface mechanism is a block-mode terminal protocol that's not so terribly different from TN3270. There's a C compiler, so if there's something vaguely like BSD sockets available (and I bet there is), you could probably port the X11 client libraries - assuming that hasn't already been done - and display on an X server on a Linux or Windows box, to get GUI support.

      OS 2200 is quite secure. It's a B1 system. Has a fair number of integration points with desktop OSes, too, thanks to things like Kerberos and CIFS support.

  6. Richard Steiner


    I can see doing freeware development for OS2200 here. I have the source for a number of things which I used to play with at work, and I still have an interest in playing in that environment.

    I wonder if UEDIT would run? :-) Or VSH? Or CSHELL? CALL is actually not a bad language.

    I also see it as just being interesting from a curiosity standpoint. How many 36-bit word addressable platforms are around today? I'm not sure what tools and compilers this would come with, but as long as you can get a copy of @CAT/@ELT, you can get software from here:

  7. PlinkerTind

    IBM z/OS emulator

    There is also an IBM Mainframe emulator called TurboHercules. An old Nehalem 8-socket will give 3.200 MIPS which is a mid sized IBM Mainframe. Todays x86 cpus are maybe 3x faster than Nehalem as they have 3x more cores, of course IPC and other improvements will boost performance much more than 3x, but let's stay on the pessimistic side and count with 3x faster.

    So, a new 8-socket x86 server will give ca ~10.000 MIPS under software emulation with TurboHercules. If someone ported the IBM Mainframe software to x86, it would run 5-10x faster as software emulation incurs a penalty of 5-10x slower. That means a 8-socket x86 today would give somewhere between 50-100.000 MIPS, which is in par with the largest IBM Mainframe (which has around 75.000 MIPS I think). In other words, IBM Mainframes costs $millions but are slower than x86.

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