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

[Jay Jaeger]

On 12/21/2018 4:00 PM, Bill Degnan wrote:
> 
> 
> On Fri, Dec 21, 2018 at 4:47 PM Jay Jaeger via cctalk
> <cctalk at classiccmp.org <mailto: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 <mailto: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

Unless, of course, none of them found their way into customers' hands.