RFC 1064 (rfc1064) - Page 2 of 26
Interactive Mail Access Protocol: Version 2
Alternative Format: Original Text Document
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
Crispin