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62902Current status of MTS ?

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  • Robert Hodge
    Oct 19, 2010
      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@...>

      > 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.


      [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

      [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]
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