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␈↓ ↓N␈↓α␈↓ ε⊃␈↓εDIALNET
␈↓ ↓N␈↓ε␈↓ ¬	␈↓John McCarthy and Les Earnest␈↓ n
␈↓ ↓N␈↓α␈↓ α↑1.  The Dialnet Concept                     ␈↓ π∞␈↓allows␈α
interaction␈αamong␈α
programs␈αin␈α
di≥erent
                                            ␈↓ π∞␈↓computers.
␈↓ ↓N␈↓␈↓↓Dialnet␈↓␈αwill␈αbe␈αa␈αset␈αof␈αprotocols␈α(like␈αthose␈αof
␈↓ ↓N␈↓the␈α
ARPAnet)␈α
enabling␈α∞a␈α
computer␈α
user␈α∞at␈α
a         ␈↓ π∞␈↓These␈α≠facilities␈α≠have␈α≠proven␈α≠valuable␈α~in
␈↓ ↓N␈↓terminal␈αattached␈αto␈αhis␈αown␈αcomputer␈αto␈αsend      ␈↓ π∞␈↓aiding␈αcollaboration␈αamong␈αcomputer␈α
scientists
␈↓ ↓N␈↓messages␈α~to␈α~users␈α→of␈α~other␈α~computers,␈α→to          ␈↓ π∞␈↓at␈αdi≥erent␈αsites␈αand␈αin␈αpermitting␈αnationwide
␈↓ ↓N␈↓transmit␈α_≡les␈α_between␈α_his␈α_own␈α→and␈α_other           ␈↓ π∞␈↓access␈α to␈α unique␈α∨facilities␈α such␈α as␈α∨the
␈↓ ↓N␈↓computers,␈α≤and␈α≤to␈α≤use␈α≥other␈α≤time-shared          ␈↓ π∞␈↓MACSYMA␈α system␈α for␈α!computing␈α with
␈↓ ↓N␈↓computers␈α∂directly␈α∂-␈α∞all␈α∂using␈α∂the␈α∂facilities␈α∞of   ␈↓ π∞␈↓algebraic␈α∪and␈α∩analytic␈α∪expressions␈α∪at␈α∩M.I.T.
␈↓ ↓N␈↓the␈α⊂ordinary␈α∂dial-up␈α⊂telephone␈α⊂network.␈α∂ His     ␈↓ π∞␈↓They␈α∪permit␈α∪a␈α∩new␈α∪form␈α∪of␈α∪publication␈α∩in
␈↓ ↓N␈↓computer␈α∂will␈α∂need␈α⊂a␈α∂telephone␈α∂dialer␈α⊂and␈α∂a        ␈↓ π∞␈↓which␈α∩documents␈α∩are␈α∩kept␈α∩in␈α∪the␈α∩computer,
␈↓ ↓N␈↓suitable␈α~modem␈α≠and␈α~must␈α≠implement␈α~the            ␈↓ π∞␈↓are␈α∀continuously␈α∪updatable,␈α∀are␈α∪immediately
␈↓ ↓N␈↓␈↓↓Dialnet␈↓␈α∞protocols␈α∞in␈α∞its␈α∞operating␈α∂system.␈α∞ No    ␈↓ π∞␈↓accessible␈α→throughout␈α→the␈α→country,␈α→and␈α→in
␈↓ ↓N␈↓formal␈α∞network␈α∞will␈α∞be␈α∞required;␈α∞the␈α∞users␈α∞of      ␈↓ π∞␈↓which␈αcomments␈αfrom␈αreaders␈αare␈αaccessible␈α
to
␈↓ ↓N␈↓any␈α∞computer␈α
implementing␈α∞the␈α∞protocols␈α
will     ␈↓ π∞␈↓other readers.
␈↓ ↓N␈↓be␈α
able␈αto␈α
communicate␈α
with␈αthe␈α
users␈α
of␈αany
␈↓ ↓N␈↓other␈α
computer␈α
implementing␈α
them␈α-␈α
anywhere      ␈↓ π∞␈↓The␈α
usefulness␈αof␈α
the␈α
ARPAnet␈αhas␈α
prompted
␈↓ ↓N␈↓in the world.                               ␈↓ π∞␈↓many␈α≡non-defense␈α≡installations␈α≡to␈α≡try␈α≥to
                                            ␈↓ π∞␈↓connect␈α
to␈α
it,␈αand␈α
in␈α
some␈αcases␈α
this␈α
has␈αbeen
␈↓ ↓N␈↓In␈α"July␈α#1977,␈α"the␈α#Stanford␈α"University            ␈↓ π∞␈↓possible,␈α→but␈α→usually␈α→the␈α→institutional␈α→and
␈↓ ↓N␈↓Arti≡cial␈α↔Intelligence␈α↔Laboratory,␈α↔began␈α⊗an     ␈↓ π∞␈↓≡nancial␈α≤obstacles␈α≤have␈α≤been␈α≠insuperable.
␈↓ ↓N␈↓NSF␈α≤supported␈α≤eighteen␈α≤month␈α≤study␈α≠to            ␈↓ π∞␈↓The␈α
main␈α
≡nancial␈α
obstacles␈α
are␈α
the␈α∞need␈α
for
␈↓ ↓N␈↓design␈α∞and␈α∞experimentally␈α∞implement␈α
suitable    ␈↓ π∞␈↓a␈α⊃dedicated␈α⊂computer␈α⊃called␈α⊂an␈α⊃IMP␈α⊂costing
␈↓ ↓N␈↓protocols.                                  ␈↓ π∞␈↓about␈α⊂$80,000␈α⊂at␈α⊂each␈α⊂site␈α⊂and␈α⊂the␈α⊃need␈α⊂for
                                            ␈↓ π∞␈↓dedicated␈α⊂communication␈α⊂lines␈α⊂rented␈α⊃by␈α⊂the
␈↓ ↓N␈↓While␈α
we␈αexpect␈α
the␈αmain␈α
users␈αof␈α
␈↓↓Dialnet␈↓␈αto        ␈↓ π∞␈↓Department␈α
of␈α
Defense␈α
at␈α
great␈α
expense␈α
from
␈↓ ↓N␈↓be␈αtime-sharing␈αsystems,␈αwe␈αhope␈αthe␈αprotocols    ␈↓ π∞␈↓the␈α~telephone␈α~companies.␈α~ Other␈α~networks
␈↓ ↓N␈↓will␈αbe␈αimplementable␈αby␈αsingle␈αuser␈αcomputer     ␈↓ π∞␈↓have␈α∪been␈α∪started,␈α∪some␈α∪for␈α∪particular␈α∩user
␈↓ ↓N␈↓systems,␈α∩perhaps␈α∩even␈α∩down␈α∩to␈α∩the␈α∪level␈α∩of         ␈↓ π∞␈↓populations␈αand␈αothers␈α
on␈αas␈αcommon␈α
carriers.
␈↓ ↓N␈↓hobbyist␈α≥computers.␈α≤ We␈α≥call␈α≥the␈α≤system          ␈↓ π∞␈↓However,␈α$they␈α$have␈α$higher␈α$base␈α#and
␈↓ ↓N␈↓␈↓↓Dialnet␈↓␈αby␈αanalogy␈αwith␈αARPAnet,␈αbut␈αunlike       ␈↓ π∞␈↓overhead␈α∃costs␈α∃than␈α∃can␈α∃be␈α∃achieved␈α∃with
␈↓ ↓N␈↓the␈α∞ARPAnet,␈α
it␈α∞requires␈α
no␈α∞administrator␈α
to      ␈↓ π∞␈↓direct␈α⊂use␈α⊂of␈α⊂the␈α⊂telephone␈α⊂system␈α⊂and␈α∂don't
␈↓ ↓N␈↓"admit"␈α#new␈α"members;␈α#they␈α#need␈α"only              ␈↓ π∞␈↓presently␈α
o≥er␈α
message,␈α
≡le␈α
transfer␈α∞and␈α
login
␈↓ ↓N␈↓implement␈α
the␈α
protocols␈α
and␈α
know␈α
each␈α
other's     ␈↓ π∞␈↓services.
␈↓ ↓N␈↓telephone numbers.
                                            ␈↓ π∞␈↓We␈α≠are␈α≠designing␈α≠protocols␈α≠that␈α≠can␈α≠be
␈↓ ↓N␈↓We␈α~need␈α≠and␈α~solicit␈α~the␈α≠co-operation␈α~of           ␈↓ π∞␈↓implemented␈α~at␈α~any␈α≠time-shared␈α~computer
␈↓ ↓N␈↓computer␈α)users␈α)and␈α*manufacturers␈α)in             ␈↓ π∞␈↓installation␈α⊗or␈α↔single␈α⊗user␈α↔computer␈α⊗system
␈↓ ↓N␈↓developing␈α∂protocols␈α∂that␈α∂will␈α∂be␈α∂suitable␈α∞for    ␈↓ π∞␈↓without␈α↔joining␈α⊗any␈α↔formal␈α↔network.␈α⊗ The
␈↓ ↓N␈↓standardization.␈α~ Mistakes␈α~made␈α~now␈α~may         ␈↓ π∞␈↓hardware␈α∀cost␈α∃will␈α∀be␈α∃from␈α∀$500␈α∃to␈α∀$5000
␈↓ ↓N␈↓have a long life.                           ␈↓ π∞␈↓depending␈α∀on␈α∪the␈α∀type␈α∪of␈α∀system␈α∀and␈α∪how
                                            ␈↓ π∞␈↓di≠cult␈α≤it␈α≤is␈α≥to␈α≤connect␈α≤devices␈α≥to␈α≤the
␈↓ ↓N␈↓The␈α_ARPAnet␈α_connects␈α_about␈α_a␈α_hundred             ␈↓ π∞␈↓computer.␈α" For␈α"time-sharing␈α"systems,␈α"an
␈↓ ↓N␈↓computer␈α$facilities␈α$involved␈α$in␈α#Defense         ␈↓ π∞␈↓automatic␈α≠telephone␈α~dialer␈α≠will␈α≠allow␈α~the
␈↓ ↓N␈↓Department␈α_supported␈α_research␈α_and␈α↔allows        ␈↓ π∞␈↓system␈α⊂to␈α⊂initiate␈α⊂calls.␈α⊂ For␈α⊂small␈α⊂single-user
␈↓ ↓N␈↓users␈αof␈αone␈αsystem␈αto␈αlog␈αin␈αon␈α
others,␈αallows      ␈↓ π∞␈↓systems␈αwhere␈αeconomy␈αis␈αparamount,␈αthe␈αuser
␈↓ ↓N␈↓transmission␈α↔of␈α↔messages␈α↔between␈α_users␈α↔of        ␈↓ π∞␈↓can␈α~do␈α~his␈α→own␈α~dialing.␈α~ There␈α~will␈α→be
␈↓ ↓N␈↓di≥erent␈αcomputers,␈αand␈αallows␈αthe␈αtransfer␈αof    ␈↓ π∞␈↓programs␈α∞to␈α∞transmit␈α∞signals␈α∞and␈α
information
␈↓ ↓N␈↓≡les␈α∃between␈α∃computers.␈α∃ More␈α∃generally,␈α∀it      ␈↓ π∞␈↓according␈α∪to␈α∩the␈α∪protocols.␈α∪ Any␈α∩installation
␈↓ ↓N␈↓αDialnet␈↓ `2


␈↓ ↓N␈↓implementing␈α∃the␈α∃protocols␈α∃will␈α∃be␈α∃able␈α∃to
␈↓ ↓N␈↓communicate␈α≥with␈α≡any␈α≥other.␈α≡ The␈α≥only
␈↓ ↓N␈↓disadvantage␈α⊗compared␈α⊗with␈α⊗the␈α∃ARPAnet
␈↓ ↓N␈↓will be lower speed.

␈↓ ↓N␈↓Like␈αARPAnet,␈α␈↓↓Dialnet␈↓␈αwill␈αbe␈αmost␈αuseful␈αto
␈↓ ↓N␈↓␈↓↓full␈αtime-sharing␈αsystems␈↓␈α
or␈αsingle␈αuser␈α
systems
␈↓ ↓N␈↓that␈α⊂operate␈α⊂24␈α⊂hours␈α⊂and␈α⊂have␈α⊃≡le␈α⊂systems.
␈↓ ↓N␈↓In␈α
such␈α
systems,␈αeach␈α
user␈α
has␈α
named␈αdisk␈α
≡les
␈↓ ↓N␈↓that␈α∂are␈α∂kept␈α∂in␈α∂the␈α∂system␈α∂even␈α∂when␈α∂he␈α∞is
␈↓ ↓N␈↓absent␈α(and␈αtherefore␈αremotely␈αaccessible),␈αand
␈↓ ↓N␈↓new␈α∂≡les␈α∞can␈α∂be␈α∞created␈α∂by␈α∞≡le␈α∂transfer␈α∞from
␈↓ ↓N␈↓other␈α∪machines␈α∩and␈α∪on␈α∩receipt␈α∪of␈α∩messages.
␈↓ ↓N␈↓The␈α≡usefulness␈α≡of␈α≡the␈α∨message␈α≡facilities
␈↓ ↓N␈↓normally␈α∞requires␈α∞that␈α
users␈α∞habitually␈α∞log␈α
in
␈↓ ↓N␈↓each␈α⊗working␈α⊗day␈α⊗and␈α⊗are␈α⊗most␈α⊗bene≡cial
␈↓ ↓N␈↓when␈α∞users␈α
have␈α∞individual␈α∞display␈α
terminals
␈↓ ↓N␈↓in␈α∞their␈α∞o≠ces.␈α∞ Further␈α∞bene≡ts␈α∂accrue␈α∞when
␈↓ ↓N␈↓reports␈α⊗are␈α∃normally␈α⊗prepared␈α⊗at␈α∃terminals
␈↓ ↓N␈↓and␈α∂when␈α∂secretaries␈α∞use␈α∂terminals␈α∂for␈α∞letters
␈↓ ↓N␈↓and␈α∞messages.␈α∂ However,␈α∞many␈α∂less␈α∞advanced
␈↓ ↓N␈↓installations␈α∞have␈α∞found␈α∞the␈α∞ARPAnet␈α
useful
␈↓ ↓N␈↓and␈α∃more␈α∃and␈α∃more␈α∃systems␈α∃are␈α∃acquiring
␈↓ ↓N␈↓economical full time-sharing capability.

␈↓ ↓N␈↓While␈α∂we␈α∂expect␈α∂the␈α∞≡rst␈α∂users␈α∂of␈α∂␈↓↓Dialnet␈↓␈α∞to
␈↓ ↓N␈↓be␈α∂regular␈α∂computer␈α∂users,␈α∂the␈α∂corresponding
␈↓ ↓N␈↓ARPAnet␈α∂facilities␈α∂have␈α∂been␈α∂much␈α∂used␈α∂by
␈↓ ↓N␈↓non-programmers.␈α∞ Users␈α∞of␈α∞␈↓↓Dialnet␈↓␈α∂need␈α∞not
␈↓ ↓N␈↓know␈α≡how␈α≡to␈α≡program,␈α≡and␈α∨we␈α≡expect
␈↓ ↓N␈↓increasing␈α&use␈α&by␈α&non-programmers␈α&as
␈↓ ↓N␈↓terminals become more widespread.

␈↓ ↓N␈↓The␈α⊃economics␈α⊃of␈α⊃sending␈α⊃messages␈α∩and␈α⊃≡le
␈↓ ↓N␈↓transfer␈αby␈αDialnet␈αare␈αquite␈αfavorable␈αwithin
␈↓ ↓N␈↓a␈α∪single␈α∪country.␈α∪ Using␈α∪Dialnet␈α∪for␈α∪remote
␈↓ ↓N␈↓login is economical only within a local area.

␈↓ ↓N␈↓Preliminary␈α↔protocols␈α↔may␈α↔be␈α↔available␈α↔as
␈↓ ↓N␈↓early␈αas␈αSpring␈α1978,␈α
and␈αa␈α"≡nal"␈αversion␈α
will
␈↓ ↓N␈↓be␈α∀available␈α∀by␈α∀the␈α∀end␈α∀of␈α∃1978.␈α∀ Anyone
␈↓ ↓N␈↓interested␈α_in␈α↔implementing␈α_the␈α↔preliminary
␈↓ ↓N␈↓protocols␈α∞or␈α∂in␈α∞in∨uencing␈α∂them␈α∞is␈α∂invited␈α∞to
␈↓ ↓N␈↓communicate␈α⊃with␈α⊃John␈α∩McCarthy,␈α⊃Arti≡cial
␈↓ ↓N␈↓Intelligence␈α∀Laboratory,␈α∃Stanford,␈α∀California
␈↓ ↓N␈↓94305.␈α( Alternatively,␈α(communicate␈α'with
␈↓ ↓N␈↓MCCARTHY@SU-AI on the ARPA net.