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
