21 Dec
2018
21 Dec
'18
8:30 p.m.
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 at classiccmp.org>
wrote:
On 12/21/2018 3:07 PM, Paul Koning via cctalk
wrote:
memory?
At that size and that date I suspect core rope, but that would be
pretty expensive (due to the labor involved).
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
> On Dec 21, 2018, at 3:06 PM, Bill Degnan via cctalk <
cctalk at
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
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).