[ih] Fwd: Arpanet Reconstruction Project - an update

[Jack Haverty]

Wow.  I wonder which took more person-hours -- the recent 
reconstruction, or building it all 50+ years ago.

I logged in to my old MIT-DM machine.   The 1972 Washington Hilton 
scenarios work as I remember them.   I was part of the crew that 
Licklider sent from MIT to DC to help put all that stuff together and 
get it to work.

Somehow they've even managed to reconstruct the slowness of the machine, 
and ARPANET, in 1973.   Sadly, my directory (DSK:JFH;) isn't there.  
  Couldn't find a directory for any other users of that era wither.

I thought perhaps I could fix that final bug in some program I wrote, 
and maybe go for a Guinness record for longest outstanding bug ever fixed.

/Jack

On 2/3/26 18:03, Vint Cerf via Internet-history wrote:
> sharing with permission
> v
>
>
> ---------- Forwarded message ---------
> From: Oscar Vermeulen <oscar.vermeulen at hotmail.com>
> Date: Tue, Feb 3, 2026 at 2:35 PM
> Subject: Arpanet Reconstruction Project - an update
> To: Robert Kahn <rkahn at cnri.reston.va.us>, Steve Crocker <steve at shinkuro.com
> Cc: o.oosterwijk at ceds.dev <o.oosterwijk at ceds.dev>, Leonard Kleinrock <
> lk at cs.ucla.edu>, Vinton G. Cerf <vint at google.com>, Lars Brinkhoff <
> lars.brinkhoff at gmail.com>, Charley Kline <csk at mail.com>
>
>
> Dear Sirs,
>
> We bothered you with a few emails last summer, about our "Arpanet
> Reconstruction Project" - and we promised to keep you informed.
>
> I hope you do not mind us contacting you again for such an update. But we
> have made quite some progress, enough to send you a link to a working
> Arpanet recreation:
>
> https://obsolescence.dev/arpanet_home
>
>
> This replicates a fully functional Arpanet with the topology from May 1973,
> with 35 IMP emulators connected, running their 1973 firmware. Accessible
> currently are the three MIT PDP-10s running ITS, and the Stanford SAIL
> PDP-10 running WAITS. The web page contains 8 web terminals, labelled as
> 'seats at the 1972 ICCC conference' where visitors can connect through the
> Arpanet IMPs to one of these four systems and attempt a few of the "Arpanet
> Scenarios" from the event's booklet.
>
>
>     - And this begs the question, as computer history hobbyists, did our
>     tone of voice (aimed at a general audience) capture the reality of the
>     event? We decided to shape this web page (the prototype for a museum
>     exhibit) around the idea that the 1972 ICCC conference was a breakthrough
>     event, and it is interesting to experience 'what it was that made people
>     see'. But we base ourselves on reading up decades after the event. It will
>     be very welcome to hear if perhaps we overly romanticised the event - and
>     should amend the "storyline".
>
>
> The web site with arpanet terminals acts as the prototype for:
>
>     1. An interactive museum exhibit - we dream of having some nodes located
>     at their historical locations
>     2. An open source 'arpanet in a box' package that people can run on
>     their own machines and explore/enjoy
>     3. A hobby Arpanet that our group can connect to with their replica
>     PDP-10s and -11s.
>
>
> This is only work in progress - the text of the page, the exact commands to
> relive the Scenarios - all of that will need a small group of volunteers to
> perfect before we would consider this a public site. But the setup is
> properly working, and the ITS and WAITS systems are rich enough in context
> that indeed, you will see students' messages on the Stanford machine from
> the early 70s; and ITS user directories with some well-known MIT users and
> their software projects. In other words, we believe this can truly be a
> realistic experience of the Arpanet circa 1972-3.
>
> Work is underway to reconstruct the TENEX system, and files from BBN and
> the University of Utah have been found to make these nodes more than
> sterile 'bare OS' systems. But the OS code is not trivial to get to a
> working stage, it will take some time. Also, work is underway to present
> the UCLA SDS Sigma 7 online with an operating system that is maybe not the
> period-correct one, but at least a modified CP-V that will present itself
> in a similar fashion. Also, we have the BBN Network Control Center on the
> to-do list. Of course, the IMP network already sends data to BBN's IMP node
> 5, and we are processing the data that this particular IMP sends to its
> host 0. But the end goal would be to have a replica PDP-1 handle the data
> flow. We also have high hopes to get the two original Multics machines
> online, a group of people has worked on them and the challenge will be to
> complete the missing NCP code for Multics. But that is now feasible - it
> will be done. Lastly, a period-correct PDP-11 Unix v6 with NCP connection
> sounds like it will be on the cards later this year.
>
> We'll also have a hardware replica of the H516 IMP ready as open-source
> hardware in the coming months. It is needed for museum exhibits, and
> hobbyists will enjoy it as well. We should not over-represent its
> importance: behind its replica front panel will hide a Raspberry Pi with a
> Honeywell 316 simulator running. But it will be fully functional, connect
> over serial lines or internet UDP connections to 'the reconstructed
> Arpanet' and be a nice functional museum exhibit, as we hope.
>
> (You might have forgotten, our series of replicas is at
> https://obsolescence.dev).
>
> I hope you do not mind our longish update above - too much information, I'm
> sure. But feedback of both the positive and negative kind is very welcome.
> It will help us get the historical context right. Please keep in mind
> though, that the web pages' text are only drafts. We focused on getting the
> actual Arpanet simulation working reliably first.
>
> Kind regards,
>
> Oscar Vermeulen
> Cc Lars Brinkhoff
> Cc Otto Oosterwijk
>
>
>

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