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Re: [hercules-390] Current status of MTS ?

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  • rhtatum
    No, MTS probably won t run under Hercules - I looked up MTS using a google search, and it seems that there was an additional operation code that the folks that
    Message 1 of 214 , Oct 19, 2010
      No, MTS probably won't run under Hercules - I looked up MTS using a google search, and it seems that there was an additional operation code that the folks that created MTS either did themselves or had IBM implement for switching between pieces of MTS, user programs, etc. Someone would have to write the simulation code for that op-code for MTS to run under Hercules-390. Other than that, machine operation codes are machine operation codes, and if a program/operating system/whatever runs on the "real iron", it will run under Hercules.

      The history of TSS/360 and MTS is interesting - first IBM would support themt, then they wouldn't, then they would, then they wouldn't. When they figured/found out that there were folks that were paying money to use the stuff, they decided it was a good idea.

      I still wonder just how much money it cost IBM to make their floating-point stuff on the original S/360 work properly - any applied mathematician could have told them that one first normalizes all the results in a computation, then truncates the final result, not the other way around. The very idea of adding two positive, non-zero numbers and having the sum be less than either summand was bizarre, as a bunch of folks of Stanford pointed out, rather vigorously, back around 1966/67. I've heard anywhere from a few mil to around $25M, since they not only had to mod machines being built, but also all those out in the field.

      I don"t think IBM internally was all that coordinated - I was on contract to IBM in Poughkeepsie in 1969 and had to use a 360/40 for some weird MIS (Manufacturing Information System) they wanted a bunch of coders to build, and just out of curiousity, I tried out the floating-point instructions the machine had. Son-of-a-gun! The hardware hadn't been fixed. I asked the Customer Enfgineer assigned to keep the machine running about that, and he replied that he didn't even know that the machine had floating-point hardware on it! Wonderful, amazing, fantastic, ...

      ----- Original Message -----
      From: Robert Hodge
      To: hercules-390@yahoogroups.com
      Sent: Tuesday, October 19, 2010 6:40 PM
      Subject: [hercules-390] Current status of MTS ?



      With all this talk about MTS, is there any way someone could get a copy of MTS
      and run it under Hercules? I read the wiki's you mention below and it brings
      back a lot of memories. I used to use MTS at Wayne State University for a
      number of years. It wasn't perfect, but it did a lot of things right, and many
      external companies paid the universities for accounts to run MTS thru dial-up
      modems. It was mostly a lot of fun, for those days.

      ________________________________
      From: Mike Alexander <mta@...>
      To: hercules-390@yahoogroups.com
      Sent: Tue, October 19, 2010 5:47:09 PM
      Subject: Re: [hercules-390] HW failures, self-modifying code. Was: Re: Should we
      give up on Yahoo ?


      --On October 19, 2010 1:45:07 PM -0500 rhtatum <rhtatum@...>
      wrote:

      > As a matter of historical interest, when was MTS doing thes things
      > (different storage keys for monitor, user code, data)? Mike wrote
      > something called the elpar Moniter/OS circa 1970 that did just that -
      > if you tried to write and execute self-modifying code or scribble o9n
      > the monitor, you got got kicked off the machine immediately with a
      > memory protect violation.

      MTS started using storage keys for protecting shared memory around 1966
      or 1967. As time went on much more sophisticated protection mechanisms
      were developed to guard against accidentally or intentional damage to
      the system and storage keys became much less relevant. There is a
      paper [1] that describes the state of the world circa 1977. This
      predates Named Address Spaces and a number of other protection related
      changes. There's a lot of information about MTS on Wikipedia ([2] and
      [3]). There's even a 41 year old picture of me there!

      > About reentrant code - that's simple enough; why are folks so afraid
      > of writing recursive routines?

      Reentrant and recursive are not all that closely related. Code can be
      one without being the other. Writing reentrant code isn't difficult if
      you start that way from the beginning. Retrofitting code to be
      reentrant after the fact is often much more difficult.

      Mike

      [1] Pirkola, Gary C., and Sanguinetti, John, "The Protection of
      Information in a General Purpose Time-Sharing Environment", In IEEE
      Symposium, Trends and Applications 1977: Computer Security and
      Integrity, Proceedings, pp. 106-114. Available at
      <https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxtaWNoaWdhbnRlcm1pbmFsc3lzdGVtfGd4Ojc5MTAxNzg1NTVmMjg5Mzk>

      [2] <http://en.wikipedia.org/wiki/Michigan_Terminal_System>

      [3] <http://en.wikipedia.org/wiki/MTS_system_architecture>

      [Non-text portions of this message have been removed]





      [Non-text portions of this message have been removed]
    • Jay Maynard
      ... Jim, Gerard, and Scott, please take this to private email. -- Jay Maynard, K5ZC http://www.conmicro.com http://jmaynard.livejournal.com
      Message 214 of 214 , Nov 20, 2010
        On Sat, Nov 20, 2010 at 04:09:57PM -0000, n9gtm wrote:
        > If you were looking for just how far is too far, you found it.

        Jim, Gerard, and Scott, please take this to private email.
        --
        Jay Maynard, K5ZC http://www.conmicro.com
        http://jmaynard.livejournal.com http://www.tronguy.net
        http://www.hercules-390.org (Yes, that's me!)
        Buy Hercules stuff at http://www.cafepress.com/hercules-390
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