[ih] Early email systems

[Jaap Akkerhuis]

 Dave Crocker writes:

 > > UNIX background processes: what I am looking for is an understanding 
 > > about how they became invoked in email systems: were they perhaps part 
 > > of POP of IMAP protocols? Or introduced in some other way when an email 
 > > goes astray or to an unknown address?
 >
 > Pop was much later.  IMAP was much, /much/ later.
 >
 > I think you are looking for asynchronous return error messages, and I 
 > don't remember when those first started showing up. Messages were being 
 > queued for asynchronous transfer -- and therefore asynchronous error 
 > handling -- by the mid-/late-70s.


I get the impression Ian wants to know how one got "You have mail" on
the terminal in UNIX. That was/is actually done by the shell. From the
manual:

     MAIL          The name of a mail file, that will be checked for the
                   arrival of new mail.  Overridden by MAILPATH.

Berkeley UNIX gave you "biff".

	jaap