21 Apr
2023
21 Apr
'23
11:58 p.m.
On Fri, Apr 21, 2023 at 10:37 AM Noel Chiappa <jnc(a)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.