6 Apr
2013
6 Apr
'13
12:53 p.m.
On 6 April 2013 13:59, David Riley <fraveydank at gmail.com> wrote:
I wouldn't swear to the fact that there
weren't 11/23s sold as 18-bit
systems; my fuzzy memory says that 11/23 might have been 18-bit while
11/23+ would have been 22-bit. Other people doubtless know better
than me; my other recollection is that the "plus" distinction has to
do with the KDF11-B board (which has the boot ROM and SLUs).
I don't know anything about how DEC sold their machines, but I do believe
they
did sell the 11/23 as an 18-bit system (even though the KDF11A is very
much capable of 22-bit), as I remember there is a "PDP-11/23" version of
the BA11-N box (with H9273-A, the BA11-N always has the H9273-A; except
special OEM boxes that might just have an H9275-A -- or a hobbyist (or
company that was too cheap/clever to get a 23+ box) who has upgraded their
BA11-N to an H9275-A); as well as a "PDP-11/03L" version of the BA11-N box
(the difference between the two being only the front plate, which on the
11/03-L version is all white, including the "background" of the logotype,
while the 11/23 has the "background" of the logo painted black (to make it
more visible)).
The 11/23+ comes in the BA11-S box, which while also a 9-slot long
backplane, is the H9276-A backplane which is by default a Q22/CD backplane;
I don't think the H9275-A can fit into a BA11-S box, though.
I really want to get my hands on a PDP-11/03L version of the BA11-N box;
I'm still trying to replace my "lost" PDP-11 system, and at present all
I've got is a CPU and an H9275-A backplane. (I like the "all white" front
plate, looks nicer in my opinion.) Nevermind that though, I'm going astray
of the original topic.
Cheers,
Christian