7 Jul
2005
7 Jul
'05
2:17 a.m.
On Thu, 7 Jul 2005 00:13:47 +0100 (BST)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
Even where IBM cards of that era used 'commodity' components, they were
usually completely house-marked and impossible for a mere mortal to
figure out. This goes all the way down to resistor networks and
resistors/capacitors (except those few that have color-code bands.)
IBM was an empire unto itself.
Size is
probably a big issue, but DEC made some big
machines and IBM made some small ones, and the DEC
boxes still seem to get more attention from
collectors. I think that the relative availability of
DEC hardware, software, and documentation simply makes
I suspect is is partly the doucmentation. DEC machines of this period
tended to come with schematics rather than board-swapper guides (which
is what the IBM service manuals I've seen were). There are thus plenty
of PDP8, PDP11, etc shematics around.
And IBM used custom parts a lot earlier than DEC. I've not seen a 370,
but I'd be suprised if it was all off-the-shelf components. Unibus
PDP11s PDP8s, etc tended to be.