Are you sure the referenced early PDP-11/10 wasn't really the PDP-11/15?
We got an 11/15 because it was cheaper and DEC had one sitting around
that we could get with end of year left over budget funds.
On 12/21/18 2:00 PM, Bill Degnan via cctalk wrote:
On Fri, Dec 21, 2018 at 4:47 PM Jay Jaeger via cctalk <cctalk@classiccmp.org>
wrote:
On 12/21/2018 3:07 PM, Paul Koning via cctalk wrote:
On Dec 21, 2018, at 3:06 PM, Bill Degnan via cctalk <
cctalk@classiccmp.org> wrote:
My _guess_ is that that probably happened because there is no formal
'model'
for that first one (unlike the first -11, which got re-named the -11/20
BITD), and people recently picked that to disambiguate them from all
the
other -8's.
The original PDP 11 was sold in two model options, although the numbers
did
not appear on the faceplace, very clearly the model options were called
PDP
11/10 and PDP 11/20. These are just as legitimate and well defined as
the
11/05 vs. 11/10 (later version) that followed it except for the one
fact of
the front plate. The fact that the name does not appear on the front
panel
has caused every DEC historian to miss this factoid. Read the first
brochure, don't take my word for it.
http://vintagecomputer.net/browse_thread.cfm?id=593
Momentum prevents change I get it, but it's clear that the model 11/20
and
11/10 existed from day one. The problem is that DEC re-used the 11/10
model name again a few years later, the other cause for neglecting the
original 11/10 model.
Bill
Wow.
Did that V1 11/10 ever ship? Do any still exist?
I'm curious about that 1 kW read-only memory. What technology is that
memory? At that size and that date I suspect core rope, but that would be
pretty expensive (due to the labor involved).
paul
It shows up in the pdp11 handbook 1969 inside/1970 on the spine, and
pdp11 handbook 2nd edition (also 1969/1970), but has been displaced by
the latter 11/10 variant by 1972.
Perhaps, since the *only* difference was the memory configuration (near
as I can tell), there may have been so few orders (maybe even none?)
that they just dropped it. Or maybe a marketing / design team
communication misstep.
The pdp11 handbook from 1969/1970 identifies the memory attributed to
the 11/10 only as read-only core memory with an access time of 500ns
(same as the RAM core). It describes the tiny RAM for the 11/10 of 256
words has having a 2us cycle time vs. 1.2us for the 11/20.
The handbook also indicates that an 11/20 could do an NPR transfer every
1.2us but an 11/10 could do one ever 1.0us (probably assuming ROM cycle
times).
As a guess, they may never have sold any (or delivered 11/20's to those
who ordered 11/10's).
When you consider the differences between the 11/35 and 11/40 were simply
option choices and the later 11/10 11/05, I can see no reason why the
"original 11/10 11/20 is any different other than the front plate being
"PDP-11" for the later pairing. I am unaware of any 11/10's still around
but I am also unaware of any Rolm 1601's that still exist, does not mean it
was not a real Ruggednova model. etc.
Basically it's being inconsistent to not acknowledge the original 11/10.
We could say that the PDP 11 models were
11/20
11/45
11/40
11/10
... and ignore the original 11/10, plus the 11/35 and 11/05.
I will still sleep well at night regardless what officialdom decides. :-)
Bill
