The first transatlantic cable was laid out between 1854 and 1858 an...
Reservisor
*Terminal on the left and drum memory units on the ri...
The Hollerith machine was an electromechanical machine designed to ...
This is what a typical reservation center looked like in 1949. A bi...
Starting in the 1950s the number of air passengers would explode wo...
**Teleregister stock display**
Large screens displayed current d...
[Here](http://archive.computerhistory.org/resources/text/Teleregist...
**Baudot Code** is a character set predating ASCII that was invente...
The **Mark I** was a general purpose electromechanical computer dev...
[Here](https://d.lib.ncsu.edu/computer-simulation/videos/julian-rei...
The Reservisor Automated Airline
Reservation System: Combining
Communications and Computing
JON
EKLUND
Shortly after the beginnings of the computer in the mid-
1940s,
a machine
appeared that was the first in a long line of important commercial systems inte-
grating communications and processing: the Reservisor airline reservation
system built by the Teleregister Corporation.
A
few parts of the original have
been preserved at the Smithsonian Institution, and there are enough records
to understand both the basic issues in the airline industry that led to the devel-
opment of this remarkable device and how the machine helped solve some of
the problems of rapidly evolving air-transport technology. This article also dis-
cusses the place
of
the Reservisor in the larger view of the development of in-
formation technology.
odern information technology is historically founded
M
on two deep footings: communications and process-
ing. While both can be traced back beyond the historical
record, arguably the greatest change in each occurred when
their technologies became electrically driven.
As the first truly “modern” technology, communications
led the way into the age of the immediate with the Morse
telegraph in the late 1830s. Not long after came the popular
miracle of the Atlantic cable. which connected continents.
From the effort to carry multiple telegraph signals on
a
single wire (since erecting telegraph lines was fearfully ex-
pensive) came the telephone in the 1870s. The name “wire-
less” correctly suggests
a
desire to avoid that enormous
economic drawback
-
wires
-
which plagued both the
telegraph and telephone. Sending signals through the air (or
ether)
was
but one more miracle from
a
long line of unfore-
seen leaps into hard-to-believe futures for communications
technology in the nineteenth century. The leaps from wire-
less to radio to television are familiar to most of us. Thus
were spawned the “glamour industries” of most periods in
the nineteenth and twentieth centuries.
Curiously, electrically driven processing on
a
large scale
lagged communications by nearly
a
century, perhaps be-
cause the
modification
of information inherently requires
more steps and internal subsystems than
moving
it.
To
be
sure, the Hollerith machine and its card-based electrome-
chanical descendants were impressive and important, but
their impact on the social and commercial world was not on
the same scale
as
the telephone or even the telegraph.
Indeed, influences of that scale did not happen until the
advent of computers which, of course, have turned out to be
the quintessential information engines.*
~~___
*
In May
1990,
the National Museum
of
American History opened
the most extensive and complex technology exhibition in the
As we
also
know. there has been
a
clear trend to combine
processing and communications technologies in various
ways and to varying degrees.
For
example, digital processing
technology now plays
a
central role in television. Beyond
the obvious ever more elaborate graphics and animation
tricks lies the crucial infrastructure of digital switching. In
the last year
or
so,
the media have trumpeted ambitious
plans for “information highways” to transmit unimaginable
amounts of computer data. For even longer periods, news-
paper articles and other media sources have let the public in
on the trendy and even useful fun of computer bulletin
boards and commercial “on-line” services. Less well known
is the fact that, shortly after the beginnings of the computer
in the mid-1940s,
a
machine appeared that was the first in
a
long line of important commercial systems integrating com-
mercial communications and processing: the Reservisor air-
line reservation system built by the Teleregister Corpora-
tion. As far
as
we know,
all
that survives of the system is an
agent set. two racks, and
a
magnetic-drum memory, which
are now housed in the Smithsonian Institution.**
The background to the Reservisor
system: The reservations problem
Whether an airline flight was short or long, the problem
was in sending and receiving immediate and accurate infor-
mation. An oversold flight meant angry passengers. On the
other hand, an unoccupied seat suffered an immediate 100
percent markdown
as
the plane closed its doors.
Smithsonian‘s history: “The Information Age.” This introductory
material is from the original themes
of
the exhibition.
*:b
The agent‘s set is now on display in the exhibit “Beyond the
Limits“ in the National Air
and
Space Museum. This exhibit covers
the history
of
computers in aerospace technology.
.
~~ ~~ ~~
105H
hlh0144
$1
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c
IO94
IEEE
62
IEEE
Annals
of
the
Hittory
of
Corripputing,
Vol.
16.
No.
1.
1994
Early methods of airline reservations were ingenious
make-do systems based
on
the systems used for slow-mov-
ing Pullman accommodations. The basic technology con-
sisted of telephone calls made by agents. Flights were han-
dled from the point
of
origin. This had a somewhat different
meaning in the immediate postwar period. The gains in the
range of airplanes developed during World War I1 would
take a few years to come into wide use in commercial
aviation. Limited ranges meant that longer flights were
broken up into “legs.” Each “leg” was treated as an origina-
tion. Longer flights meant that a ticket agent had to combine
legs by phoning a
series
of origination points.
Flight information was sent and received through a com-
plicated system of manual operations. The booking point
had a manual display board (often using chalk) which re-
corded the number of available seats
on
a particular flight.
Local agents were in sight range
of
the board: some even
used binoculars. Agents or travelers from other locations
seeking reservations by phone suffered from time lags in-
volved in getting, using, and modifying the data
on
availabil-
ity of flights. Advance sales or cancellations might be initi-
ated by letter, by telephone, or in person. But all ended up
as a written record at some point. sent to a central inventory
control unit. There was inevitably much guesswork about
selling or not selling seats, and many frustrations and diffi-
culties in communicating effectively with agents,
as
most
reservations information exchange was done by phone.
Overbooking was reportedly common.
If
anything, return
reservations were even more difficult
to
do.
A point-of-origin agent could see the board, of course,
but the official availability data was that held in the central
ticketing office. If there was a question about seat availabil-
ity, even the local agent had to call this office. As air travel
increased, it became clear that the system was
on
its way to
breakdown.’
Other ideas for automating airline
reservations
There are indications of one or two early conversations
and proposals to automate reservations in some way or
another. Ralph Damon, president of American Airlines,
was approached by Sperry in 1945 with an offer to design a
system. Damon was obviously not convinced, since the air-
line selected Teleregister later the same year.
In
1947, well after the Teleregister effort was under way.
Engineering Research Associates of St. Paul, Minnesota
(later bought out by Sperry) wrote a “Proposal for Auto-
matic Space Reservations System,” which featured the use
of
an
electric typewriter as the input and output device. In
the same year, the
Sr.
Paul Dispatch
carried an announce-
ment that Northwest Airlines had access to some kind of
device that could give a yes or
no
on
requests for airplane
seats. There is
no
evidence that either
of
these two systems
was ever built.
American Airlines takes up the challenge
Just after the war, with a clear vision of the potential
problem, the head of American Airlines’ Systems and Meth-
ods Division, Charles Ammann, researched the various
existing methods for handling seat inventories.
He
con-
cluded that all were as limited as those of his own com-
pany. Carefully analyzing the various aspects
of
American’s traditional “request and reply” and “sell and
There was inevitably much guesswork
about selling seats and frustration in
communicating with agents, as most
reservations information exchange
was done by phone.
report” systems, Ammann outlined solutions to existing
bottlenecks:
1.
A new system should present the flight information
necessary for the customer’s decision immediately
and clearly.
2.
The new system should keep track of ticket sales and
cancellations as they occur and keep up an accurate
running inventory.
3.
The agent’s machinery in the new system should re-
tain a record of the most recent transaction until
consciously cleared or until another transaction re-
placed the previous one.
4. The system should automatically let all agents and
sellers know immediately when a flight was sold out.
5.
The system should perform these tasks economically
and be capable of expansion.
Using his training as a radio engineer, Ammann built a
limited working model of an electronic inventory-control
system. The model assumed three flight legs in three days
with three agents connected to the central office. Relays
served as storage, and availability was indicated by lights.
Simple push-button switches set up availability queries.’
Ammann brought this model to the president of Ameri-
can Airlines and sold him on the idea
of
a flight reservation
system? After considering various possibilities for a com-
mercial developer for the project, American Airlines nego-
tiated with the Teleregister Corporation in 1945 for its
construction.
The Teleregister Corporation
Teleregister was founded in the 1920s to handle the
display of stock market transactions using automated dis-
play boards instead of handwritten entries
on
chalkboards.
The founder was Frenchman Philip Dreyfus, who had been
in the French signal corps. Dreyfus was familiar with French
signal techniques such as Baudot codes. which were more
sophisticated than the Morse system. He became a pioneer
in the teletypewriter and teleprinter business. It is said that
he got the idea of displays during the growth of the stock
business in the 1920s. Large Teleregister boards became
fixtures at many brokerage offices, and Teleregister became
the leader in this technology.
IEEE
Annals
of
the
History
of
Computing,
Vol. 16,
No.
1,
1994
63