Groups > alt.folklore.computers > #234484

Re: Self-hosting and the 6502

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From	Bob Eager <news0009@eager.cx>
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Subject	Re: Self-hosting and the 6502
Date	31 Mar 2026 09:49:43 GMT
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On Tue, 31 Mar 2026 09:01:05 +0100, David Wade wrote:

> On 31/03/2026 00:32, Lev wrote:
>> Bob Eager wrote:
>> 
>>> I studied this back in the early 1970s with a Honeywell 516.
>>> It didn't have real memory management, but it had two mode.
>>> Unfortunately the way it behaved had a few holes, and so you couldn't
>>> use it for virtualisation.
>>>
>>> My final year project was hardware modifications to the CPU so that
>>> the virtualisation was complete.
>> 
>> That's a fascinating data point. You had to modify hardware to close
>> the holes - meaning the Popek-Goldberg requirements really were
>> requirements, not just theoretical niceties. Did you have to trap
>> specific instructions that leaked privileged state, or was it more
>> about adding missing mode distinctions?
>> 
>> 
> To return to Microprocessors, the original 68000 did not satisfy the
> Popek-Goldberg requirements, but the later 68010 did, so broke a few
> things...
> 
> ... not sure if any software used this....

In case anyone is interested...I don't remember all of it, and I've lost 
my report, but see here:

 https://www.bobeager.uk/anecdotes.html#CPUhack


-- 
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
 http://www.mirrorservice.org

Thread

Re: Self-hosting and the 6502 Lev <thresh3@fastmail.com> - 2026-03-30 23:32 +0000
  Re: Self-hosting and the 6502 snipeco.2@gmail.com (Sn!pe) - 2026-03-31 00:36 +0100
    Re: Self-hosting and the 6502 Lev <thresh3@fastmail.com> - 2026-03-31 03:08 +0000
      Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-31 07:45 -0700
        Re: Self-hosting and the 6502 Bob Eager <news0009@eager.cx> - 2026-03-31 14:56 +0000
  Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-30 23:38 +0000
    Re: Self-hosting and the 6502 antispam@fricas.org (Waldek Hebisch) - 2026-04-01 16:50 +0000
      Re: segments, was Self-hosting and the 6502 John Levine <johnl@taugh.com> - 2026-04-02 03:07 +0000
        Re: segments, was Self-hosting and the 6502 scott@slp53.sl.home (Scott Lurndal) - 2026-04-02 16:21 +0000
          segments and architectural experimentation (was Re: segments, was Self-hosting and the 6502) Kragen Javier Sitaker <kragen@canonical.org> - 2026-09-11 08:13 -0300
            Re: segments and architectural experimentation (was Re: segments, was Self-hosting and the 6502) Peter Flass <Peter@Iron-Spring.com> - 2026-09-11 07:29 -0700
            Re: segments and architectural experimentation (was Re: segments, was Self-hosting and the 6502) john larkin <jl@glen--canyon.com> - 2026-09-11 07:55 -0700
              Re: segments and architectural experimentation (was Re: segments, was Self-hosting and the 6502) David Schultz <david.schultz@earthlink.net> - 2026-09-11 13:06 -0500
            Re: segments and architectural experimentation (was Re: segments, was Self-hosting and the 6502) someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-09-14 16:45 +0000
  Re: Self-hosting and the 6502 David Wade <g4ugm@dave.invalid> - 2026-03-31 09:01 +0100
    Re: Self-hosting and the 6502 Bob Eager <news0009@eager.cx> - 2026-03-31 09:49 +0000
  Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-31 07:31 -0700
    Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-31 23:45 +0000
      Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-31 17:15 -0700
        Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-01 01:27 +0000
          Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-31 19:24 -0700
            Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-01 03:01 +0000
              Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-04-01 07:26 -0700
                Re: Self-hosting and the 6502 "Kerr-Mudd, John" <admin@127.0.0.1> - 2026-04-01 15:54 +0100
                Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-01 20:35 +0000
                Re: Self-hosting and the 6502 snipeco.2@gmail.com (Sn!pe) - 2026-04-01 21:49 +0100
                Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-01 16:08 +0000
                Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-01 20:34 +0000
                Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-04-01 14:29 -0700
                Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-01 22:37 +0000
                Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-01 22:52 +0000
        Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-01 13:54 +0000
        Re: Self-hosting and the 6502 antispam@fricas.org (Waldek Hebisch) - 2026-04-01 17:31 +0000
  Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-31 22:23 +0000

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