Which has always struck me as a bit odd, since the PDP-11 family was designed to be just that, a family. So you'd think that "marketing" would have kept that in mind when designing the first front panel label ... -----Original Message----- From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Pontus Pihlgren Sent: Monday, February 22, 2016 3:12 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: PDP-11/20 vd one that just says pdp 11 what are the date differences?? OEM? The PDP-11/20 was the first PDP-11. I believe the number was added when the other models came out, to discern them. /P On Mon, Feb 22, 2016 at 03:03:17AM -0500, COURYHOUSE at aol.com wrote: differences??

I wonder how long it took them to "figure it out"? I seems that the family-plan dates to April 1969. June 1970 seems to be generally quoted as the introduction date for the PDP-11/20. And then June 1972 for the 11/10. My PDP-11 is labeled as "S-386" and dated 9/23/70, which I guess makes it fairly early in the production run (but I do wonder what the initial manufacturing rate was given the relative riskiness of this new architecture). Anyone have S# and dates for "plain 11" vs. 11/20-marked for comparison? -----Original Message----- From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Pontus Pihlgren Sent: Monday, February 22, 2016 3:27 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: PDP-11/20 vd one that just says pdp 11 what are the date differences?? OEM? On Mon, Feb 22, 2016 at 03:25:36AM -0500, Paul Birkel wrote: ... Indeed, and it's just something I've "heard" so there might actually be another reason. /P

Agreed; I neglected to mention that mine also is marked in that manner! Seems like DEC had ramped up to about 15-20 machines/day by mid-September. Guess that the front panel graphics guys "didn't yet get the memo". Or maybe someone was hedging their bets against an ignominious sales failure in the initial front panel production? -----Original Message----- From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Christian Corti Sent: Monday, February 22, 2016 4:32 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: RE: PDP-11/20 vd one that just says pdp 11 what are the date differences?? OEM? On Mon, 22 Feb 2016, Paul Birkel wrote: Our PDP-11 is labeled as "S-308", the date is 9/16/70. And I think they called it PDP11-20 from the beginning, as the model number above the serial number says "M11-20" Christian

On Mon, Feb 22, 2016 at 07:07:35AM -0500, william degnan wrote: I will definitely correct myself in the future. It would be interresting to see if anyone has a "numberless" machine with the "M11-10" designation printed on the back, to see if any was actually delivered (and I wouldn't be surprised if there was). /P

On Mon, Feb 22, 2016 at 07:16:24AM -0500, william degnan wrote: Hmm, notice that it says "Turnkey Console" which I believe means it lacks the lights and switches console? /P

Here is January 1970 Datamation "product of the month" with more info http://vintagecomputer.net/digital/PDP11-20/PDP11_Articles_1970Jan.pdf b

On Mon, 22 Feb 2016, Paul Birkel wrote: When everybody realized and accepted that there would be more than one sub-model, and decided that it might be handy to be able to tell them apart. There may have been some holdouts in some departments, such as silk-screening the panels. By analogy, the phrase "single density" didn't originally exist. After "DOUBLE-density" was developed, THEN "single density" needed a name. Although just sticking with "FM" and "MFM" would have been a lot better! (Although I guess that it was inevitable that marketing would invent "HD", instead of "double data transfer rate MFM".) There were even a few companies that freely intermingled HEADS V density! Intertec/Superbrain decided to call their 5.25" 40 track DSDD, "QUAD density", because it was twice the capacity of the 40 track SSDD! Then, when they added an 80 track DSDD, they caalled that "SUPER density", abbreviated "SD"! So, if you encounter an alien disk labelled "SD", it might be 720K/800K, not 100K. Similarly, if you were to search ancient archives, the phrase "World War TWO" was first used BEFORE there was any mention of "World War ONE". It wan't until a second happened, or was expected, before anybody had any reason to declare the "Great war"/"World War" to be "nuber ONE". So, the use of any sort of "first" name doesn't occur until "second" is expected.