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6299Re: [cosmacelf] 1802 Emulations

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  • Chris Elmquist
    Jan 1, 2010
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      Very interesting,

      http://www.computer-refuge.org/bitsavers/pdf/xerox/parc/techReports/ISL-83-1_A_Retrospective_on_the_Dorado_A_High-Performance_Personal_Computer.pdf

      Lots of very new concepts in processor and system design deployed there--
      including scan path/boundary scan testing and debug.

      They do say though that the machine was mostly ECL rather than TTL-- with
      an instruction cycle of 60nS.

      cje

      On Thursday (12/31/2009 at 11:53PM -0600), Lee Hart wrote:
      > J.C. Wren wrote:
      > > I've been writing firmware for 2^5 years, and seen a lot of processors come
      > > and go. I looked at the Propellor when it first came out, but I couldn't
      > > get myself interested in it. Maybe something like the Propellor Starter Kit
      > > that cwardell2000 mentioned might be a way. It's probably that I couldn't
      > > find a use for it...
      >
      > One of my favorite computers was the Dorado, made by Xerox in the 1970's
      > as the the platform to run Smalltalk on. It had a microprogrammable CPU,
      > made with TTL chips. What was neat about it was that the instruction set
      > was not fixed; it was downloaded from disk to suit the application
      > program being run.
      >
      > This meant it could emulate all the different CPUs of the day at full
      > speed. It had emulations of the 8080, 8085, Z80, 6800, 6502, etc. I
      > don't know if there was one for the 1802, but it certainly could have
      > done it.
      >
      > More importantly, it could emulate the special *hardware* that various
      > computers had. It *became* a TRS-80, Apple II, IMSAI 8080, etc. I am
      > sure it could become an ELF or VIP as well, if someone wrote the code.
      >
      > The Propeller is the first modern chip I've seen that might be able to
      > perform this sort of trick.
      > --
      > Lee A. Hart | Ring the bells that still can ring
      > 814 8th Ave N | Forget the perfect offering
      > Sartell MN 56377 | There is a crack in everything
      > leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

      --
      Chris Elmquist
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