Re: Frank Heart, Who Linked Computers Before the Internet, Dies, at 89 [telecom]

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On 6/30/2018 5:30 AM, HAncock4 wrote,

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The article doesn't credit Frank Heart with inventing those things. He  
led the project that built the original ARPANET IMPs. Progress is built  
on the shoulders of others who came before. Much of the computer world  
doesn't take things like reliability seriously. BBN did.

I worked at BBN in the late 1970s (ARPANET era) and knew Frank, though I  
didn't work for him. I was corporate telecom manager. Frank was a VP, a  
Division Director by then. BBN had a rather unique culture, where  
computing was combined with both usability (human factors) and  
reliability. One of their products was the Pluribus TIP, a variant on  
the ARP that was used as a terminal server (this was the 1970s). It  
contained several CPUs. If one failed, the others would try to repair  
it. It was famously hard to turn off, as its CPUs kept trying to restart  
each other!

...
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The ARPANET data lines were leased from Ma by Uncle Sam, not us. The  
backbone was type 303 modems on group channel (48 kHz wide) circuits,  
providing 50 (not 56) kbps. This was truly exotic for the day, when the  
Long Lines network was all analog.

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the_Transmission_of_Pulses_Over_Telephone_Lines_Apr54.pdf
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BBN used many then-existing ideas, including error detection via CRC.  
IBM was already doing that. Modems go back much earlier, to the TWX  
network if not earlier. Humorously, when I returned to BBN in 1994, some  
of the new managers were spreading the idea that BBN had invented the  
modem. Which was laughable if you knew about them, but by then the  
history of the modem was not well known. BBN had in fact built a hack  
(in the 1960s) called Datadial, which was a sort of pre-touchtone  
interactive system, sort of like an auto-attendant, that remotely  
decoded dial pulses! It didn't go anywhere. I never heard of it in the  
1970s, but somebody found out about it in the 1990s and confused it with  
a modem.


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