[ih] Question re rate of growth of the Arpanet

[Dave Crocker]

On 4/22/2025 8:23 AM, Johan Helsingius via Internet-history wrote:
> Pretty much, yes. Leaf nodes could survive on a 1200 bps connection,
> but I don't think I ever saw anything slower. 


MMDF was initially developed for use by the Army Materiél Command, in 
1979, but a year or two later it was applied to the initial operation of 
CSNet, the forerunner to NSFNet.

It's role was as an email gateway to Arpanet mail (and then, of course, 
Internet Mail.)  Its contact with these 'distant' participants was over 
dial-up.  Although X.29/X.25 could be used to emulate a phone call, most 
connections really were via telephone.

Speeds were 300 or 1200 baud, where I think 300 was the most common 
initially.

It was quite noteworthy that having email transfer take place entirely 
in the background made even 300 baud useful for email traffic of those 
days.  Users simply did not have to know or care what the connection 
speed was, since the transfer happened 'away' from them.

There was, however one problem this model had: Users were not aware what 
the connection speed was, or when there were problems.

One day, I got a call from a site's admin claiming that no mail was 
getting through.  There would be a connection for about an hour and then 
it would break off, repeating at the next wake-up cycle.

Looking at the logs showed that the queue was stuck on trying to send a 
1MB file... sigh.

The user environment that I shipped with MMDF contained some 
alternatives, but the popular choice was code that emulated BBN Tenex`s 
SNDMSG(*) and ISI's MSG(**).  This was in the days long before there was 
official support for attachments, but people would include files 
anyhow..  In SNDMSG, do a Ctl-B and you stuffed the file into the 
message.  You did not have to know or care how big it was.  sigh.

The dial-up link simply could not sustain a data call long enough.


d/


(*) SNDMSG was the program Ray Tomlinson hacked, to create the first 
'networked' email, in 1971.

(**) MSG was written by John Vittal and was functionally derived from 
the first email program, RD, that let you selectively read mail; it was 
developed by the Arpa CS lead, Larry Roberts, albeit I hear some other 
folk had more than little involvement.  More significant was that MSG 
was the first program to have a reply command, those its constrained 
command model forced choose 'A'nswer, instead. The presence of that 
function altered email use dramatically, since it meant someone 
responding did not have to laboriously fill out address and subject info 
each time.

-- 
Dave Crocker

Brandenburg InternetWorking
bbiw.net
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