[ih] Nit-picking an origin story

[Jack Haverty]

John's right - it would be more accurate to say that event was passing 
the first messages on the ARPANET.

History tends to think of the ARPANET as the first experiment in packet 
switching.  Opinions differ of course...

But another important innovation was ARPANET's ability to interconnect 
different kinds of computers, from different manufacturers, with wildly 
different architectures of hardware and software.  Prior to 1969, there 
were many computers interconnected by telephone circuits.   But they 
were generally homogeneous environments, most of which were based on IBM 
computers and terminals.

Most people on this list would probably not consider a "multidrop line" 
as a "network", but that was a common technique for connecting a bunch 
of machines together, using a single "multidrop" circuit daisy chained 
through the bunch.  IIRC, protocols involved were things like HDLC and 
SDLC.

I remember a job I had while a student at MIT circa 1968, which involved 
terminals in classrooms talking to mainframes at IBM in New York to run 
APL programs for thins like hydraulics analysis.  My job was to get it 
all up and running and fix any problems when the students attacked.  
Phones (and modems) seemed especially attractive to students even in 
those days.  What does this button do...???

Re testing: Yes, BBN tested extensively before shipping boxes out to the 
field.  Ben Barker was one of the hardware guys working on the IMP in 
1969, and he was the engineer who travelled with the IMPs to California 
to set up those first two nodes.   Back in 2012 Ben and I exchanged a 
bunch of emails about the early ARPANET days, as part of research for a 
patent battle where the IMP was to be prominent as evidence of "prior art".

Here's a snippet of his recollections about "IMP 1" as BBN was preparing 
to ship it - from the guy who actually did the work:

 > Just before we were to ship IMP 1, we had a problem where the machines
 > would crash mysteriously about once per 24 hours.  It was a weird crash,
 > with the PC pointing at a completely random place, typically in a 
chain of
 > non-executable locations in a data structure, with no way it could have
 > gotten there.  The location before would have caused a crash, there 
were no
 > jumps to it (with or without indexing ior indirection). I concluded 
that it
 > had to be a race condition with the heavy use of the DMC channel.  I went
 > through the Honeywell drawings of the 516 processor and found a place 
where
 > the timing looked too tight.  I figured a way to  patch it in the
 > processor.  I rewired it less than 24 hours before scheduled ship.  It
 > fixed the problem and the machine shipped on schedule.  We had a heck 
of a
 > time convincing Honeywell that they had this fundamental design flaw 
in the
 > central timing chain of their machine, but they eventually were convinced
 > and made the change in their future machines.
 >

So there was extensive testing before IMP 1 was shipped, including 
redesign of the hardware when necessary to catch a failure that only 
occurred in testing about once per day.

I didn't join BBN until 1977, but I remember that there was still 
extensive testing of new releases of IMP hardware and software. 
Sometimes tests were run literally for months or more.

Enjoy,
/Jack Haverty

On 8/16/25 10:16, John Day via Internet-history wrote:
> The NPL network already existed and had for awhile, a couple of years but I will have to go look at sources to be exact.
>
> Of course, what this should say is the first messages exchanged on the ARPANET.
>
> I am sure BBN tested it before they delivered it, but I don’t remember now what Hafner says about that.
>
> Take care,
> John
>
>> On Aug 16, 2025, at 12:41, Dave Crocker via Internet-history<internet-history at elists.isoc.org> wrote:
>>
>> My Facebook feed just delivered a tidbit from UCLA that begins:
>>
>>    "In 1969, UCLA Professor Leonard Kleinrock directed the transmission
>>    of the first message between two networked computers..."
>>
>> I found myself wondering a bit about that characterization:
>>
>> 1. Didn't BBN do some inter-host packet exchanges, when testing the
>>    IMPs, before shipping them to UCLA and SRI?  Wouldn't that have
>>    counted as the actual first?
>> 2. There were other packet research projects, at the time, but I don't
>>    remember the details of timing of other 'WAN' and 'LAN' project.
>>    1969 was early enough that it's entirely possible the others were
>>    later, but I'd be interested in hearing the details.
>>
>> I suspect the refinement of the UCLA statement would be:
>>
>>    "In 1969, UCLA Professor Leonard Kleinrock directed the transmission
>>    of the first message between two networked computers
>>
>> -- 
>> Dave Crocker
>>
>> Brandenburg InternetWorking
>> bbiw.net
>> bluesky: @dcrocker.bsky.social
>> mast: @dcrocker at mastodon.social
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