[ih] More Topology, Packet Radio

[vinton cerf]

that must have been when Barry Leiner was running the PRNET/SURAN programs?

v


On Tue, Aug 31, 2021 at 3:07 PM Barbara Denny via Internet-history <
internet-history at elists.isoc.org> wrote:

>  Upon reflection I want to mention I think 6.2 supported multiple stations
> in a Packet Radio network.  I believe an earlier release supported a single
> station. I just don't remember if that version was something like Cap5
> versus Cap6.
> barbara
>     On Tuesday, August 31, 2021, 09:01:55 AM PDT, Barbara Denny <
> b_a_denny at yahoo.com> wrote:
>
>   Eventually under the SURAN contract we/SRI got a version of the radio
> code.  What we received was probably BCPL because at this point I am
> thinking I got asked to do a modification because I was probably the only
> one around with BCPL experience from the Packet Radio station software.
> There is a chance it was in C.  The big thing I remember was the code
> reminded me of more like something that might have been written by people
> used to a lower level language, like assembler.
> My memory might be wrong but I seem to remember Packet Radio had 256 byte
> packets.
> The different CAP version numbers indicated functionality in the Packet
> Radio network so if I remember correctly CAP6.2 included the Packet Radio
> Station while CAP7 was stationless.
> barbara
>     On Tuesday, August 31, 2021, 05:56:47 AM PDT, Lawrence Stewart via
> Internet-history <internet-history at elists.isoc.org> wrote:
>
>  I can contribute a few bits of information about the Packet Radio Network.
>
> In 1978 I designed the 1822 interface for the Xerox Alto.  It was used to
> connect to the Bay Area Packet Radio Network and for connecting PARC-MAXC2
> to the Arpanet.
>
> The Radios used an entirely different low level protocol than the IMPs.
> It was called CAP, for Channel Access Protocol.  CAP was notable for a very
> small MTU - it had an 11 (16-bit) word header and up to 116 words of data.
>
> PARC used the PRNet for a while to encapsulate PUP traffic between the
> PARC building and the Xerox Advanced Systems Devision (Ben Wegbreit and
> Charles Simonyi) building.
>
> I wrote the CAP driver in Mesa, for connection to Hal Murray’s Mesa
> Gateway code.  It may still be around, in the files Paul McJones put up on
> the CHM servers at
> http://xeroxalto.computerhistory.org/Indigo/Alto-1822/.index.html <
> http://xeroxalto.computerhistory.org/Indigo/Alto-1822/.index.html>
> The BCPL test software for the 1822 is definitely there.
>
> I don’t know what language the radio code used. It was written by Collins
> Radio and they had (from SRI accounts) a truly stone age attitude about
> it.  The master version was kept in a box of cards in the manager’s office.
>
> I found the writeup of the Xerox work in IEN-78 at
> http://www.watersprings.org/pub/rfc/ien/ien78.pdf <
> http://www.watersprings.org/pub/rfc/ien/ien78.pdf>
>
> -Larry
>
> I guess I am surprised by the comments here about the subleties of the
> 1822 distant host signaling.  I don’t think the Alto board had
> optoisolaters and it did work in both local and distant host modes, but was
> never tried with very long cables or ground problems.
>
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