[ih] from whence cometh ">" ?

[Craig Partridge]

Well, I can add some partial light.

The original mbox format, used by Ray Tomlinson was that there was no
format.  Mail was simply appended to a file which you read with your text
editor.  Ray included a From: field (but not To:) and Subject: and Date:
(see RFC 561).

This was a PITA to the first email program writers because it was
murderously hard to parse the mailbox.  As a result, in 1973 Martin Yonke
(author of BananaRD, the first standalone mail reading program and
successor to Larry Robert's RD [a set of TECO macros]) decided that mail
systems when delivering to a mailbox should separate emails with 4 SOH
(Start of Header) characters -- and that's how most do it by default to, I
believe, the present day.

Some systems persist, instead, on finding a From: field as a delimiter
which creates the >From requirement.

Craig

On Tue, Oct 14, 2025 at 1:59 PM Brian E Carpenter via Internet-history <
internet-history at elists.isoc.org> wrote:

> There's a slightly related point which I found mentioned in RFC 4155,
> which defined the application/mbox media type:
>
> >    Many implementations are also known to escape message body lines that
> >    begin with the character sequence of "From ", so as to prevent
> >    confusion with overly-liberal parsers that do not search for full
> >    separator lines.  In the common case, a leading Greater-Than symbol
> >    (0x3E) is used for this purpose (with "From " becoming ">From ").
>
> MBOX format is notoriously variable and under-documented. RFC 4155 cites
> http://qmail.org./man/man5/mbox.html which implies that everybody knows
> about ">". If anybody can find the *original* specification of the MBOXO
> format (that is not a typo) that might help.
>
> Regards/Ngā mihi
>     Brian Carpenter
>
> On 15-Oct-25 02:38, Craig Partridge via Internet-history wrote:
> > I just spent half an hour digging through the msggroup, tcp-ip and
> > header-people mailing lists from the mid to late 1970s and none of them
> use
> > the diple.
> >
> > So I'm guessing it was an innovation in one of the email or netnews
> reading
> > tools developed in the late 1970s to early 1980s.  There are lots of
> > choices that appeared about that time: readnews, rn, Berkeley Mail (?),
> MH
> > and, I think, some Emacs reading tools.
> >
> > Craig
> >
> > On Tue, Oct 14, 2025 at 5:04 AM Eliot Lear via Internet-history <
> > internet-history at elists.isoc.org> wrote:
> >
> >> Hi Internet Historians,
> >>
> >> I wonder if anyone knows the earliest use of "> " as a means to quote
> >> text.  A research here in Switzerland is asking me.  I can only date it
> >> as far back as "rn" and netnews, but surely it goes back beyond 1984.
> >> The researcher mentioned that there have been various forms of a
> >> "diple"[1] as Ancient Greece and in the bible.  But when did it get
> >> picked up in Internet times?
> >>
> >> Any takers?
> >>
> >> Thanks,
> >>
> >> Eliot
> >>
> >> [1] https://en.wikipedia.org/wiki/Diple_(textual_symbol)
> >>
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> >
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