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.every heading(,|%7DIALNET and Home Computers↓←%1John McCarthy and Les Earnest↓
.←%2Stanford University|);
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.s The Dialnet Concept
%2Dialnet%1 will be a set of protocols (like those of the ARPAnet)
enabling a computer user at a terminal attached to his own computer
to send messages to users of other
computers, to transmit files between his own and other computers,
and to use other time-shared computers directly - all using the
facilities of the ordinary dial-up telephone network.
His computer will need a telephone dialer and a suitable modem
and must implement the %2Dialnet%1 protocols in its operating system.
No formal network will be required; the users of any computer implementing
the protocols will be able to communicate with the users of any
other computer implementing them - anywhere in the world.

In July 1977, the Stanford University Artificial Intelligence Laboratory,
began an NSF supported
eighteen month study to design and experimentally implement
suitable protocols.

While we expect the main users of %2Dialnet%1 to be time-sharing systems,
we hope the protocols will be implementable by single user
computer systems, perhaps even down to the level of
hobbyist computers.
We call the system %2Dialnet%1 by analogy with ARPAnet,
but unlike the ARPAnet, it
requires no administrator to "admit" new members; they need only
implement the protocols and
know each other's telephone numbers.

We need and solicit the co-operation of
computer users and manufacturers in developing protocols that
will be suitable for standardization.  Mistakes made now may
have a long life.
.every heading(%3Dialnet,,{PAGE!});

	The ARPAnet connects about a hundred computer facilities
involved in Defense Department supported research
and allows users of one system to log in
on others, allows transmission of messages between users
of different computers, and allows the transfer of files between
computers.  More generally, it allows interaction among programs in
different computers.

	These facilities have proven valuable in aiding
collaboration among computer scientists at different sites and in
permitting nationwide access to unique facilities such as the MACSYMA
system for computing with algebraic and analytic expressions at
M.I.T.  They permit a new form of publication in which documents are
kept in the computer, are continuously updatable, are immediately
accessible throughout the country, and in which comments from readers
are accessible to other readers.

	The usefulness of the ARPAnet has prompted many non-defense
installations to try to connect to it, and in some cases this has
been possible, but usually the institutional and financial
obstacles have been insuperable.  The main financial obstacles are
the need for a dedicated computer called an IMP costing about $80,000
at each site and the need for dedicated communication lines rented by
the Department of Defense at great expense from the telephone companies.
Other networks have been started, some for particular user populations
and others on as common carriers.  However, they have higher base and
overhead
costs than can be achieved with direct use of the telephone system
and don't presently offer message, file transfer and login services.

	We are designing protocols that can be implemented at any
time-shared computer installation
or single user computer system without joining any formal network.
The hardware cost will be from $500 to $5000 depending on the type of system
and how difficult it is to connect devices to the computer.
For time-sharing systems, an automatic telephone dialer
will allow the system to initiate calls.
For small single-user systems where economy is paramount, the user can do his
own dialing.
There will be programs to transmit signals and information according
to the protocols.  Any installation implementing the protocols will
be able to communicate with any other.  The only disadvantage compared
with the ARPAnet will be lower speed.

	Like ARPAnet, %2Dialnet%1 will be most useful to %2full
time-sharing systems%1 or single user systems that operate 24 hours
and have file systems.  In such systems, each user has named disk
files that are kept in the system even when he is absent (and
therefore remotely accessible), and new files can be created by file
transfer from other machines and on receipt of messages.  The
usefulness of the message facilities normally requires that users
habitually log in each working day and are most beneficial when users
have individual display terminals in their offices.  Further benefits
accrue when reports are normally prepared at terminals and when
secretaries use terminals for letters and messages.  However, many
less advanced installations have found the ARPAnet useful and more
and more systems are acquiring economical full time-sharing
capability.

	While we expect the first users of %2Dialnet%1 to be
regular computer users, the corresponding ARPAnet facilities have
been much used by non-programmers.  Users of %2Dialnet%1 need not
know how to program, and we expect increasing use by non-programmers as
terminals become more widespread.

	The economics of sending messages and file transfer by
Dialnet are quite favorable within a single country.  Using Dialnet
for remote login is economical only within a local area.

	Preliminary protocols may be available as early as Spring
1978, and a "final" version will be available by the end of 1978.
Anyone interested in implementing the preliminary protocols or in
influencing them is invited to communicate with John McCarthy,
Artificial Intelligence Laboratory, Stanford, California 94305.
Alternatively, communicate with MCCARTHY@SU-AI on the ARPA net.