Original PDP-11/10 [was: Re: Origin of 'Straight 8' name]

[David C. Jenner]

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:
>>>
>>>
>>>> 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
>> 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
>