[TUHS] pseudo tty history

[Aron Insinga]

The RFC refers to "the Harvard PDP-10 System" and "Harvard's PDP-1" in 
the first paragraph, and the "MITDG PDP-6/10" (so that's 2 machines but 
eventually MIT had a gaggle of PDP-10s) in the second paragraph.  And  
of course MIT had a PDP-1, where Spacewar was developed and first 
played.  I don't know the arrival/exit dates of the machines.

Here are some dates, but I don't know if they are just samples based on 
the earliest DECUS submission from there, or installation dates. The 
Harvard museum (which has pieces of the Mark I) may know more about when 
different machines were installed and removed.

http://www.bitsavers.org/pdf/dec/pdp1/PDP-1_SerialNumbers.txt
> Sites known to have PDP-1's based on DECUS submissions:
> ...
> Harvard University                     Dec 64
> ...
> MIT Lincoln Laboratory Group 22        May 65
> MIT Laboratory For Nuclear Science     Apr 65
> MIT Project MAC                        Jul 64
> MIT RLE                                Sep 65

By serial number:
> 05  PDP-1C  MIT (RLE)
> 26  PDP-1C  MIT
> 37  PDP-1C  MIT Lincoln Labs                11/65
> 40  PDP-1C  MIT (MAC)                        64(?)
> 41  PDP-1C  Harvard
> 53  PDP-1   MIT

Side note: I saw the MIT PDP-6 with its chess trophies on top of it 
during the Blizzard of '78.  (After I interviewed at DEC, I made my way 
from Marlborough through the rapidly-intensifying snow to Cambridge to 
visit someone from High School.  I ended up crashing on a dorm sofa from 
the day the blizzard hit until the airport in Boston reopened which was 
about a week.)  The PDP-6 had a sign on it that said something like 
"This machine is old and flaky so don't touch it unless you know what 
you are doing."

- Aron

On 8/16/25 10:57, Clem Cole wrote:
> Right.  What I do not know is what early machines Harvard had from 
> DEC.  MIT had the 18 and 36 bit series which was what I was implying.  
> The key point though is that if Harvard was the root of the PTY tree 
> it would have been on one of those systems not a Unix system because 
> Unix did not come to Harvard until 1974 and RFC 89 was 1971 and RFC 46 
> in 1970
>
> Sent from a handheld expect more typos than usual
>
>
> On Fri, Aug 15, 2025 at 8:50 PM Aron Insinga <aki at insinga.com> wrote:
>
>     The https://datatracker.ietf.org/doc/html/rfc89 mentions a PDP-6
>     and PDP-10s which are 36-bit twos complement machines, and a DEC
>     PDP-1 which was an 18-bit one's complement  machine.  The
>     "graphics-oriented" PDP-1 probably had the well-known Type 30
>     display which used a large round radar-type CRT thanks to the
>     Project SAGE tradition, but there were a couple of other graphics
>     display options for the PDP-1.
>     https://www.computerhistory.org/pdp-1/graphics/
>
>
>     - Aron
>
>
>     On 8/15/25 23:35, Clem Cole wrote:
>>     Watch the dates - that's not UNIX.  In 1973, Version 4 Unix is
>>     first released outside of BTL, so the Harvard system being talked
>>     about in RFC 89 is probably an 18 bit ??PDP6 maybe??.
>>
>>     On Fri, Aug 15, 2025 at 8:24 PM Bakul Shah via TUHS
>>     <tuhs at tuhs.org> wrote:
>>
>>         From RFC 89 (dated 19 January 1971) titled "Some historic
>>         moments in networking":
>>
>>            Second, the Harvard system has temporarily implemented
>>         this remote
>>            network console interface feature using a DEC style
>>         pseudo-teletype
>>            (PTY).
>>
>>         From RFC 46 (dated April 1970) titled "'ARPA Network Protocol
>>         Notes":
>>
>>            3. A standard way for a newly created process to initiate
>>         pseudo-
>>               typewriter communication with the foreign process which
>>         requested
>>               its creation.
>>
>>
>>>         On Aug 15, 2025, at 6:49 PM, ron minnich
>>>         <rminnich at gmail.com> wrote:
>>>
>>>         was there ever a telnet or other remote access program that
>>>         predated ptys on Unix? Was telnet the driving force for
>>>         ptys? Did the folks implementing Unix networking bring in
>>>         ptys before, or as part of, or after networking, i.e. did
>>>         folks building networking for Unix realize they needed ptys
>>>         once they started working on telnet, or did they plan for
>>>         ptys from the get go? I was an observer for some of this
>>>         stuff, but as a 20-year-old at UDEL I was also quite out of
>>>         the loop.
>>>
>>>          I also realize there were multiple Unix networking efforts,
>>>         so this question is somewhat simplistic.
>>>
>>>         I'm assuming rsh came a bit later.
>>>
>>>         On Fri, Aug 15, 2025 at 4:19 PM Tom Lyon <pugs78 at gmail.com>
>>>         wrote:
>>>
>>>             Yeah, I was thinking that 4.1c BSD must've had them for
>>>             rlogin and telnet.
>>>
>>>             Which got me looking for Fabry and Bill Joy's
>>>             design/planning documents for 4.2, which are not in the
>>>             TUHS archives.
>>>             Anyone got them??
>>>
>>>             On Fri, Aug 15, 2025 at 4:15 PM Warner Losh
>>>             <imp at bsdimp.com> wrote:
>>>
>>>                 At the very least, 4.2BSD had them for telnet and
>>>                 rlogin. They were static, though. You had to MAKEDEV
>>>                 enough units.
>>>
>>>                 Warner
>>>
>>>                 On Fri, Aug 15, 2025, 5:00 PM ron minnich
>>>                 <rminnich at gmail.com> wrote:
>>>
>>>                     That was my guess. I figured the people who did
>>>                     the work are on this list, and primary sources rule.
>>>
>>>                     On Fri, Aug 15, 2025 at 3:56 PM Ron Natalie
>>>                     <ron at ronnatalie.com> wrote:
>>>
>>>                         I think that wikipedia history is somewhat
>>>                         garbled when it comes to the UNIX
>>>                         implementations.
>>>
>>>
>>
>
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