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Groups > alt.folklore.computers > #234550

Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502]

From Rich Alderson <news@alderson.users.panix.com>
Newsgroups alt.folklore.computers
Subject Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502]
Date 2026-04-01 15:41 -0400
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <mddv7eampsr.fsf_-_@panix5.panix.com> (permalink)
References <10qdbas$2991c$1@dont-email.me> <10qdsqr$2fj63$1@dont-email.me> <10qj0dd$65ea$1@dont-email.me>

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Gordon Henderson <gordon+usenet@drogon.net> writes:

  [ snip ]

> So now I had my OS running on a RISC-V emulator written in BCPL running on an
> OS written in BCPL running on the '816. Turtles all the way, as may be said.

> It was slow but usable as a test bed before I found suitable actual RISC-V
> hardware.

When XKL was developing their first product, code named "ToaD" = "10 on a desk",
the primary work was done on a DECSYSTEM-2065 running TOPS-20 v6.1 (which I
upgraded to v7.0 when I got there a couple of years later).

Because the Toad was an extended clone of the KL-10 processor, featuring full
30 bit addressing, changes needed to be made to TOPS-20 to support the memory
model in its full glory.

Ralph Gorin[*] wrote an emulator for the Toad in assembly language.  This executed
all instructions natively on the KL-10; the primary difference was that the
JSYS ("Jump to SYStem") instruction was assembled as an unused opcode rather
than the defined 104, so that the emulator program could use all the OS facilities
directly without interference from the emulated system.

Once we had working hardware, regression testing against the emulator had us up
and running in days rather than weeks.

[*] Ralph is of course the author of _Assembly Language Programming for the
    DECSYSTEM-20_, first edition published by Digital Press (a DEC subsidiary).
    Among other hats he wore in the startup phase of XKL was "Chief System Architect".

-- 
Rich Alderson					  news@alderson.users.panix.com
      Audendum est, et veritas investiganda; quam etiamsi non assequamur,
	  omnino tamen proprius, quam nunc sumus, ad eam perveniemus.
									--Galen

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Thread

Self-hosting and the 6502 Lev <thresh3@fastmail.com> - 2026-03-30 01:16 +0000
  Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-30 06:12 +0000
    Re: Self-hosting and the 6502 thresh3@fastmail.com (Lev) - 2026-03-30 07:07 +0000
      Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-30 08:13 +0000
        Re: Self-hosting and the 6502 thresh3@fastmail.com (Lev) - 2026-03-30 13:11 +0000
          Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-30 14:25 +0000
            Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-30 07:40 -0700
              Re: Self-hosting and the 6502 Bob Eager <news0009@eager.cx> - 2026-03-30 17:02 +0000
                Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-31 21:35 +0000
                Re: Self-hosting and the 6502 Bob Eager <news0009@eager.cx> - 2026-03-31 22:31 +0000
                Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-01 10:44 +0000
                Re: Self-hosting and the 6502 Bob Eager <news0009@eager.cx> - 2026-04-01 10:47 +0000
                Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-01 13:57 +0000
              Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-31 21:34 +0000
                Re: PC/IX, was Self-hosting and the 6502 John Levine <johnl@taugh.com> - 2026-04-01 02:01 +0000
              Re: Self-hosting and the 6502 "Kurt Weiske" <kurt.weiske@realitycheckbbs.org.remove-a96-this> - 2026-04-02 07:35 -0700
            Re: Self-hosting and the 6502 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-04-01 18:14 -0400
              Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-01 22:56 +0000
                Re: Self-hosting and the 6502 Rich Alderson <news@alderson.users.panix.com> - 2026-04-01 21:44 -0400
                Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-04-01 21:35 -0700
          Re: Self-hosting and the 6502 Nuno Silva <nunojsilva@invalid.invalid> - 2026-03-30 15:25 +0100
            Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-30 07:42 -0700
          Re: Self-hosting and the 6502 Gordon Henderson <gordon+usenet@drogon.net> - 2026-04-01 11:43 +0000
            Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] Rich Alderson <news@alderson.users.panix.com> - 2026-04-01 15:41 -0400
              Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-01 22:16 +0000
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] Rich Alderson <news@alderson.users.panix.com> - 2026-04-01 21:51 -0400
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] Peter Flass <Peter@Iron-Spring.com> - 2026-04-01 21:37 -0700
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-02 10:50 +0000
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] Rich Alderson <news@alderson.users.panix.com> - 2026-04-02 15:18 -0400
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-03 13:13 +0000
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-02 10:58 +0000
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] Peter Flass <Peter@Iron-Spring.com> - 2026-04-02 07:32 -0700
                Re: Self-hosting and the PDP-10 [was Re: Self-hosting and the 6502] cross@spitfire.i.gajendra.net (Dan Cross) - 2026-04-02 18:23 +0000
      Re: virtualization, Self-hosting and the 6502 John Levine <johnl@taugh.com> - 2026-03-30 16:28 +0000
    Re: Self-hosting and the 6502 Bill Findlay <findlaybill@blueyonder.co.uk> - 2026-03-30 17:59 +0100
      Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-30 21:24 +0000
  Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-30 14:16 +0000
    Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-30 07:35 -0700
      Re: emulation, virtualization, Self-hosting and the 6502 John Levine <johnl@taugh.com> - 2026-03-30 16:39 +0000
        Re: emulation, virtualization, Self-hosting and the 6502 ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2026-03-30 17:20 +0000
          Re: emulation, virtualization, Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-31 23:39 +0000
            Re: emulation, virtualization, Self-hosting and the 6502 scott@slp53.sl.home (Scott Lurndal) - 2026-04-02 14:57 +0000
              Re: emulation, virtualization, Self-hosting and the 6502 rbowman <bowman@montana.com> - 2026-04-02 18:04 +0000
                Re: emulation, virtualization, Self-hosting and the 6502 scott@slp53.sl.home (Scott Lurndal) - 2026-04-02 18:45 +0000
      Re: Self-hosting and the 6502 David Wade <g4ugm@dave.invalid> - 2026-03-30 18:03 +0100
      Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-30 21:23 +0000
      Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-31 23:05 +0000
    Re: Self-hosting and the 6502 John Ames <commodorejohn@gmail.com> - 2026-03-30 07:57 -0700
      Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-30 22:19 +0000
        Re: Self-hosting and the 6502 Nuno Silva <nunojsilva@invalid.invalid> - 2026-03-31 00:18 +0100
          Re: Self-hosting and the 6502 cross@spitfire.i.gajendra.net (Dan Cross) - 2026-03-31 22:04 +0000
    Re: Self-hosting and the 6502 Bob Eager <news0009@eager.cx> - 2026-03-30 17:07 +0000
  Re: Self-hosting and the 6502 antispam@fricas.org (Waldek Hebisch) - 2026-03-31 03:34 +0000
    Re: Self-hosting and the 6502 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-31 03:54 +0000
      Re: Self-hosting and the 6502 antispam@fricas.org (Waldek Hebisch) - 2026-03-31 05:01 +0000
    Re: Self-hosting and the 6502 Lev <thresh3@fastmail.com> - 2026-03-31 05:26 +0000
    Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-31 07:48 -0700
      Re: machine simulation, Self-hosting and the 6502 John Levine <johnl@taugh.com> - 2026-03-31 18:06 +0000
    Re: Self-hosting and the 6502 scott@slp53.sl.home (Scott Lurndal) - 2026-03-31 15:03 +0000
    Re: Self-hosting and the 6502 Bill Findlay <findlaybill@blueyonder.co.uk> - 2026-03-31 18:23 +0100
      Re: Self-hosting and the 6502 Peter Flass <Peter@Iron-Spring.com> - 2026-03-31 13:04 -0700

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