RFC 993 (rfc993) - Page 1 of 28
PCMAIL: A distributed mail system for personal computers
Alternative Format: Original Text Document
Network Working Group David D. Clark (MIT)
Request for Comments: 993 Mark L. Lambert (MIT)
Obsoletes: RFC-984 December 1986
PCMAIL: A Distributed Mail System for Personal Computers
1. Status of this Document
This document is a discussion of the Pcmail workstation-based distri-
buted mail system. It is a revision of the design published in NIC
RFC-984. The revision is based on discussion and comment from a
variety of sources, as well as further research into the design of
interactive Pcmail clients and the use of client code on machines
other than IBM PCs. As this design may change, implementation of
this document is not advised. Distribution of this memo is unlimit-
ed.
2. Introduction
Pcmail is a distributed mail system providing mail service to an ar-
bitrary number of users, each of whom owns one or more workstations.
Pcmail's motivation is to provide very flexible mail service to a
wide variety of different workstations, ranging in power from small,
resource-limited machines like IBM PCs to resource-rich (where
"resources" are primarily processor speed and disk space) machines
like Suns or Microvaxes. It attempts to provide limited service to
resource-limited workstations while still providing full service to
resource-rich machines. It is intended to work well with machines
only infrequently connected to a network as well as machines per-
manently connected to a network. It is also designed to offer disk-
less workstations full mail service.
The system is divided into two halves. The first consists of a sin-
gle entity called the "repository". The repository is a storage
center for incoming mail. Mail for a Pcmail user can arrive exter-
nally from the Internet or internally from other repository users.
The repository also maintains a stable copy of each user's mail state
(this will hereafter be referred to as the user's "global mail
state"). The repository is therefore typically a computer with a
large amount of disk storage.
The second half of Pcmail consists of one or more "clients". Each
Pcmail user may have an arbitrary number of clients, typically
single-user workstations. The clients provide a user with a friendly
means of accessing the user's global mail state over a network. In
order to make the interaction between the repository and a user's
clients more efficient, each client maintains a local copy of its
Clark & Lambert