[TUHS] off-topic: resurrecting the IMP

[Clem Cole]

+1

As for reliability.  The CMU IMP at one time was near one of the big
printer from the PDP-10's and often became a temporary resting place for
something if you had to deal with a printer jam, change paper etc.  I have
memories of the time a milkshake got knocked/spilled into the IMP in the
summer of 76 or 77.  IIRC: somebody was smart enough to pull the breaker on
the power.   Then placed a called to BBN and asked them what to do.
 Somewhere I had a picture of a person ??Jim Teter maybe?? acting on the
response in the parking lot: hose it down and the use hair dryers to dry it
out.

It was powered back up and worked and soon appeared a sign about not
putting stuff on the IMP


On Sun, Dec 1, 2013 at 5:54 PM, Armando Stettner <aps at ieee.org> wrote:

> THIS IS SO COOL!!
>
>   aps at dec-marlboro
>   aps at rand-ai
>
>
> Begin forwarded message:
>
> > From: Aharon Robbins <arnold at skeeve.com>
> > Subject: [TUHS] off-topic: resurrecting the IMP
> > Date: December 1, 2013 1:18:26 PM PST
> > To: tuhs at tuhs.org
> >
> > Hi all.
> >
> > This may be of some interest.  From a friend at Utah:
> >
> >> Date: Sat, 30 Nov 2013 16:06:25 -0700 (MST)
> >> Subject: [it-professionals] computer history: Arpanet IMPs resurrected
> >>
> >> The simh list about simulators for early computers recently carried
> >> traffic about an effort to reconstruct and resurrect the Arpanet
> >> Interface Message Processors (IMPs), which were the network boxes that
> >> connected hosts on the early Arpanet, which later became the Internet.
> >>
> >> There is a draft of a paper about the work here:
> >>
> >>      The ARPANET IMP Program: Retrospective and Resurrection
> >>      http://walden-family.com/bbn/imp-code.pdf
> >>
> >> Utah was one of the original gang-of-five hosts on the Arpanet, and we
> >> received IMP number 4.  Utah is mentioned twice in the article, and
> >> also appears in the map in Figure 3 on page 14.
> >>
> >> One amusing remark in the article (bottom of page 7) has to do with
> >> the fail-safe design of the IMPs:
> >>
> >>      In addition ``reliability code'' was developed to allow a
> >>      Pluribus IMP to keep functioning as a packet switch in the
> >>      face of various bits of its hardware failing, such as a
> >>      processor or memory [Katsuki78, Walden11 pp. 534-538]. This
> >>      was so successful there was no simple off switch for the
> >>      machine; a program had to be run to shut parts of the machine
> >>      down faster than the machine could ``fix itself'' and keep
> >>      running.
> >>
> >> As happened with early Unix releases, machine-readable code for the
> >> IMPs was lost, but fortunately, some old listings that turned up
> >> recently allowed its laborious reconstruction, verification, assembly,
> >> and simulation.
> >
> > Arnold
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> >
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