From: John Cowan <cowan@ccil.org>
To: Noel Chiappa <jnc@mercury.lcs.mit.edu>
Cc: tuhs@tuhs.org
Subject: [TUHS] Re: UNIX "Machine Layer" Standards
Date: Fri, 21 Apr 2023 13:58:09 -0400 [thread overview]
Message-ID: <CAD2gp_TypvpzUB61c9s-6hKXgHD=WZnmF4f_5RnoWjKy4M686Q@mail.gmail.com> (raw)
In-Reply-To: <20230421143713.492DF18C0A3@mercury.lcs.mit.edu>
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On Fri, Apr 21, 2023 at 10:37 AM Noel Chiappa <jnc@mercury.lcs.mit.edu>
wrote:
> A little wrong on that date. Even the PDP-11/20 (the first -11) had a boot
> ROM:
>
The PDP-8/E, which came out in the same year, had a boot ROM if you were
using DECtape as the system device for OS/8. The bootstrap for the TD8E
DECtape controller was a full device driver 128 words long, way beyond
human toggle-in capability. It was put up in addresses 77600-77777, which
meant that you could only have 28 kwords rather than the full 32 kwords of
RAM.
In principle I suppose you could have toggled in the RIM loader (17 words)
and read in the TD8E bootstrap using either Model 33 or high-speed paper
tape, but I doubt if anyone did that. RIM format alternated between
addresses and values, with each taking up two characters on the paper tape.
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next prev parent reply other threads:[~2023-04-21 17:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-21 14:37 Noel Chiappa
2023-04-21 17:58 ` John Cowan [this message]
2023-04-21 20:36 ` Clem Cole
-- strict thread matches above, loose matches on Subject: below --
2023-04-20 15:57 Paul Ruizendaal
2023-04-20 18:57 ` segaloco via TUHS
2023-04-20 20:18 ` Steve Nickolas
2023-04-20 14:56 Paul Ruizendaal
2023-04-20 16:04 ` Warner Losh
2023-04-20 19:04 ` segaloco via TUHS
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