[ih] Arpanet line speed

[Jack Haverty]

That's an IMP interface, which was a peripheral device for the PDP-11
computers.  One of those was on the PDP-11/40 in a lab at BBN in Fall
1977, so it had become a commercial product before then.  It connected
between an IMP port, following the specifications in BBN 1822, and the
PDP-11 on the Unibus IIRC.  It didn't do much processing - just
transferred the ARPANET "messages" to and from the IMP and the computer
memory.

I wrote the first TCP for Unix, and that's how those IP packets got in
and out of the machine.  I spent many hours trying to figure out what
was going on by looking at those lights...

/Jack


On 01/18/2017 11:48 AM, Jeremy C. Reed wrote:
> This got me thinking ... is there any list of where the original IMPs 
> (and modems, etc) are located today? What museums or other places can we 
> visit to see them and learn about them (in person)?
> 
> On that note, any good museums that have exhibits for the physical 
> history of the internet?
> 
> Hopefully this list allows my attachment. This is an Digital IMP11a. It 
> is probably around 12 years newer than the original IMPs. I took this 
> photo a few years ago in a Internet Systems Consortium (ISC) warehouse 
> in Redwood City, Calif.
> 
> 
> 
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