On Wed, Aug 14, 2024 at 11:44 AM Rich Salz <rich.salz@gmail.com> wrote:
I always thought the five control-A's were a failure of imagination (never going to send binary?).
As always, it's about history and how they got there. What was reasonable for one group, over time was not for another.
To be fair, that was Bruce Borden-ism from the Rand Mailer Handler (MH). Longer before things LIKE Ease/MMDF et al., Rand was running UNIX machines on the ARPANET early on (and UUCP did not yet exist). The mailer header format needed to be RFC733 in those days. The use of the "UNIX" headers - was rather limited to a couple of programs in the Fifth and Sixth Edition. Bruce had replaced the Fifth and Sixth edition "mail" program (which was both the MUI and MTA combined), with separate programs already as part of creating this new user interface and mailer agent. Thus, a new mailbox format was fair game.
It was not a failure of imagination, binary was not an issue for Bruce - since it was not allowed in RFC733 at that point. Now, remember that many UNIX folks on the ARPANET had already switched to MH (that's why we switched to using it at CMU), so MMDF picking Bruce's format was a good idea (for them). Remember, AT&T Research is not on the ARPANET, so the mail (local to a single machine in those days) could be in any format they wanted. RFC733 (and later 822) headers were not an issue, so the funky "From:" worked fine.
As I pointed out, UCB was not on the ARPANET, so when Kurt wrote the UCB MUI and split out the MTA as delivermail, he kept the V5/V6 mailbox format (mbox) from Research. The issue came when people started using the mail system as a programmatic messaging scheme (i.e., fork: some_program | mail user) and other programs started to parse the output. More importantly, getting an ARPANET connection was difficult, so many fewer sites needed to support the ARPANET (later Internet) header format, whereas a USENET connection via UUCP was easy. So >>lots<< of people started to pick up Mail(1) [Kurt's new MUI) and did not use/know about, much less need to switch over to MH and RFC733/822.
Thus, the switch from the Research "mbox" format to Borden's scheme started to become problematic in that if the new utility "knew" about mbox, it had to be hacked if you were using MH or something that was derived from MH (like MMDF or PMDF).
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