RFC 1064 (rfc1064) - Page 2 of 26

Interactive Mail Access Protocol: Version 2

RFC 1064                         IMAP2                         July 1988


   facilities to do this.  However, this approach has several
   disadvantages:

      (1) Workstations (especially Lisp workstations) have a software
      design that gives full control of all aspects of the system to the
      user at the console.  As a result, background tasks, like
      receiving mail, could well be kept from running for long periods
      of time either because the user is asking to use all of the
      machine's resources, or because, in the course of working, the
      user has (perhaps accidentally) manipulated the environment in
      such a way as to prevent mail reception.  This could lead to
      repeated failed delivery attempts by outside agents.

      (2) The hardware failure of a single workstation could keep its
      user "off the air" for a considerable time, since repair of
      individual workstation units might be delayed.  Given the growing
      number of workstations spread throughout office environments,
      quick repair would not be assured, whereas a centralized mainframe
      is generally repaired very soon after failure.

      (3) It is more difficult to keep track of mailing addresses when
      each person is associated with a distinct machine.  Consider the
      difficulty in keeping track of a large number of postal addresses
      or phone numbers, particularly if there was no single address or
      phone number for an organization through which you could reach any
      person in that organization.  Traditionally, electronic mail on
      the ARPANET involved remembering a name and one of several "hosts"
      (machines) whose name reflected the organization in which the
      individual worked.  This was suitable at a time when most
      organizations had only one central host.  It is less satisfactory
      today unless the concept of a host is changed to refer to an
      organizational entity and not a particular machine.

      (4)  It is very difficult to keep a multitude of heterogeneous
      workstations working properly with complex mailing protocols,
      making it difficult to move forward as progress is made in
      electronic communication and as new standards emerge.  Each system
      has to worry about receiving incoming mail, routing and delivering
      outgoing mail, formatting, storing, and providing for the
      stability of mailboxes over a variety of possible filing and
      mailing protocols.

   Consequently, while the workstation may be viewed as an Internet host
   in the sense that it implements IP, it should not be viewed as the
   entity which contains the user's mailbox.  Rather, a mail server
   machine (sometimes called a "repository") should hold the mailbox,
   and the workstation (hereafter referred to as a "client") should
   access the mailbox via mail transactions.  Because the mail server



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