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John McCarthy

Computer Science Department

Stanford University

Stanford, CA 94305



June 1, 2000


This article was published in Man and Computer. Proc.


Conf., Bordeaux 1970, pp. 48-57 (Karger, Basel 1972). It is interest-

ing to compare its 1970 proposals with the current situation, 30 years

later. I have decorated it with footnotes commenting on the 1970 situ-

ation and making comparisons. Some of the improvements advocated

in the paper are still yet to come. I claim quite a few prophet points

for it.

The 1970 paper

Visionaries have often proposed 1 that homes be equipped with informa-

tion terminals each consisting of a typewriter keyboard and a screen capable

of displaying one or more pages of print and pictures. The terminal is to

be connected by the telephone system to a time-shared computer which, in

turn, has access to files containing all books, magazines, newspapers, cata-

1I was the main visionary. J.C.R. Licklider was another.

I had vague hopes for a

bandwagon effect by suggesting that there were a lot more. Doug Engelbart emphasized

collaborative work on time-shared computers.

logs, airline schedules, much additional public information not now kept, and

various files personal to the user.23

Through the terminal the user can get any information he wants, can buy

and sell, could communicate with persons and institutions, and process in-

formation in other useful ways. Such a system has never come about because

it costs too much, but with each advance in technology, it becomes more fea-

sible. I think that the technology of computers, time-sharing, terminals, and

application programming has advanced to the point where realistic estimates

are possible of the remaining advances necessary to make home consoles fea-

sible and useful. In this paper, I shall discuss the uses of the home terminal,

some potential beneficial effects on society, estimate how far we are from

a system people will pay for, and advocate some pilot projects, some stan-

dardization efforts, and some laws and regulations to prevent monopoly and

secure adequate competition.

We can start with ordinary reading. To get a newspaper or book, I type

its name or number and the first page appears. The most obvious benefits


(1) I can get any document instantly.

(2) My house is not full of paper to be sorted and put on shelves and

dusted or put in the trash. Trees are not cut down, and air pollution does

not result from burning the stuff.

Some immediately apparent disadvantages are:

(1) The expense. I will deal with this later;

(2) I cannot read in bed. The book-size portable terminal will come

later. A household may require several terminals or perhaps we may have to

compromise with sin and provide a hard copy terminal after all.4

There are two other immediate negative reactions:

(1) The average citizen is a TV fan and does not read anyway. In the

first place, our system does not need so many subscribers to be economical.

2I didn’t think much about how many computers would be required. When I did, I

underestimated it.

32000 March 2: I did not anticipate the PC or the point-and-click way of using com-

puters. The light pen was already available and it could have been used, but in fact I had

a negative attitude towards the mouse. I also expected that the user would have more

facilities for controlling the computer, e.g. to make macro operations. Point-and-click

contributed to this loss of user control although it needn’t have done so if text versions of

the actions were kept accessible.

4The hard copy terminal would have been an electric typewriter or a teletype. I did

not envisage cheap printers.

Secondly, after I have described all the bells and whistles, you will see that

even the TV fan will be tempted, and you-oh socially conscious reader–may

even want to coerce him into buying one or coerce the government into giving

him one for free.5

(2) How can you think of one more convenience and comfort when the

world will come to an end in 10 years unless menaces A, B, and C are dealt

with immediately. In the first place, I do not think the world is about to

come to an end or even that it is getting worse, and we Americans like new

gadgets. In the second place, you will see that the new information system

will make the public more responsive to the careful reasoning of you good

guys and more immune to the blatant propaganda of those bad guys.6

In order to see the effects of the new information system, suppose that all

book and newspaper information were so distributed. What changes would


At present, a newspaper or a book is a package produced by a large orga-

nization.7 In our new system, the physical production disappears allowing a

much smaller organization to put out the same packages of text and pictures.

Moreover, the user does not face a one shot decision to buy Life or Look.

He will be able to read the ’cover’ or table of contents of each and read such

items as strike his fancy, and the system will bill him for what he reads from

each source. In fact, since the cost of keeping a file of information in the

computer and making it publicly available will be small, even a high school

student could compete with the New Yorker if he could write well enough and

if word of mouth and mention by reviewers brought him to public attention.

What, then, is a publication in the new information system?

A publication is an organization that puts out a list of material it has

edited and recommends to its readers. It helps its authors produce material

that it thinks will suit the readers, and it has a financial arrangement with

them about splitting the proceeds.8

5The Government and the socially conscious have noticed the “Internet gap” and aim

to fix it. Maybe they will succeed.

6I think the 1970 doomsters were a little worse than the present day doomsters. Of

course, some of the doomsters of that day are still active, but they have toned down a


7I didn’t think of the resistance to being displaced these organizations would be able

to mount. The clearest examples of such resisters are the publication organizations of

scientific societies which are in principle non-profit organizations.

8The on-line publications do not yet think of themselves in this way.

There can be a wide variety of publications of different standards of writ-

ing and editing and different budgets for carrying out these activities.

However, they will all be equally accessible to all readers, and the only

justification for an expensive editorial organization will be that it can produce

a more popular package. The price of reading a package can be set by the


A reader may feel that he needs help in finding his way through the

totality of literature available to him. Various people will be eager to make a

living by providing it. A bookstore or library is a program that when called

shows the ’covers’ of publications. Reviewers will produce lists for him and

make money when he reads their lists or by kickbacks from the publishers.

’Reading advisers’ under some catchier name will offer to generate lists just

for him according to a profile of his interests.9.

Advertising in the sense of something that can force itself on the attention

of a reader will disappear because it will be too easy to read via a program

that screens out undesirable material.10 However, people will still want to

know what is for sale and will still want to see the seller’s story about why

they should buy it. Probably, Life will still be able to get money from

advertisers; many people will still want to know what is advertised in Life,

but those who do not want to know will be able to avoid it automatically.

Another effect is the possibility of frequent revisions of articles and books.

An author can take into account new facts or other people’s criticisms, and

the revision will take effect immediately. This raises 1984ish possibilities, so

it must be provided that old versions remain available. Those who suspect

the whole system will keep their own copies of favorite material in their

private files, on microfilm, or even on paper.

Public controversy can be carried out more expeditiously than at present.

If I read something that seems controversial, I can ask the system if anyone

has filed a reply. This, together with an author’s ability to revise his original

statement, will lead people to converge on considered positions more quickly

than at present even if they do not come to actual agreement.1112

9All this has happened

10This hasn’t really happened yet.

11There are various proposals, but this hasn’t happened yet. One can imagine Bush

and McCain “truth squads” putting on their candidates’ web sites arguments against the

positions of the other guy. Personal attacks too.

122000 June 1: Today’s New York Times has an article entitled “E-Mail Messages to

the Press Have Made the Gore-Bush Race a Cyberwar” recounting how the Gore and

Famous authors will not need publishers because their loyal readers will

have the system find their stuff automatically.

To summarize: the new information system will promote intellectual com-

petition by reducing the price of entry, will permit readers to be selective,

and will allow authors to revise material until they are satisfied that it with-

stands criticism as well as it ever will. This should make intellectual life more


The financial aspect of writing would presumably be as follows: a piece of

written material has a price for reading it (this price may be zero for amateur

writing, political propaganda, advertising, and for scientific journals). The

reader’s account is debited and the account to which the material belongs

is automatically credited. The reader will have the system balk at what he

considers overpriced material.

The new information system will have a profound effect on buying and

selling. Sellers of movies, groceries, automobiles, plumbing services and cures

for baldness will find it advantageous to list their wares in the information

system together with current prices and availability. The user can place an

order through the system as he can by telephone, but he can do much more:

(1) He can call on someone’s program to scan the sellers of sports cars and

propose what it considers the best deal. This program might even negotiate

with programs representing the sellers.

(2) He can tell the system whether last year’s cure for baldness worked

and get a summary of the opinions of those who bothered to record their

opinions of the cure he contemplates trying now.

(3) He can make an airplane or hotel reservation by interacting with a

program the airline or hotel reservation company has written to tell him

what is available. He need not suffer the delays you now get when you call

an airline or travel agent at peak hours.13

(4) Individual design and construction services can be offered through the

system although this requires the development of computer-controlled manu-

facturing techniques for various types of articles. The idea is that automated

design programs can produce designs for articles meeting individual specifi-

cations. Either by himself or in consultation with an expert, an individual

would use the system to produce a design and display how it would look

Bush campaigns send dozens of messages per day to reporters. I suppose this is a partial

realization of my 1970 prediction.

13All this has happened.

and possibly how it would perform. Candidates for individual design include

clothing, furniture, boats, electronic equipment, houses, and even cars. The

system would then produce the instructions for controlling machine tools,

fabric cutters, and also printed instructions for the hand parts of the oper-

ation. In general, it should be possible to make single objects at little more

cost than present mass produced objects. In some cases, there would even

be savings, because mass production requires estimates of demand that are

often wrong resulting in inventories that are expensive to sell or even have to

be sold at a loss; the cost of this is made up by a general increase in prices.14

There are many more useful services that can be offered through the

new information system and again the system is conducive to competition.

Writing and storing a program and announcing its availability can be a very

low capital operation, and the system can collect whatever price has been

set for its use.

We could go on listing services that would come to be offered in a fully

developed system, but now we shall list some services to smaller groups of

users that are cheaper to provide and which will help get the system started.

(1) Calculation and facilities for writing, running, and debugging com-

puter programs: This does not interest the general public much, but it is

the present bread and butter of the time-sharing service bureaus that will

grow into the new information system. At present, these service bureaus

offer a very convenient way of doing small scientific and engineering calcula-

tions, but do not offer reasonable prices for big computations, and are only

beginning to offer useful services to business firms.

(2) Editing: Anyone who writes (writers, journalists, scientists, advertis-

ing men, engineers and students) will benefit from using an editor program.

It allows easy revision, can be made to check spelling, grammar, and punc-

tuation, and will produce justified or other forms of elegant output and also


(3) Filing: Keeping personal files in the computer has great advantages

once documents can be entered without retyping them, either because they

have been prepared in a computer readable form or because a suitable page

reader is available. Namely, one can retrieve any document on the basis of

its characteristics without having taken the trouble to file it properly in the

first place.

(4) Education: Computer-aided instruction (CAI) has advanced to the

14This hasn’t happened yet. Maybe it will.

point that a number of courses or aids to traditional courses have been devel-

oped and have been shown to be useful. The main obstacle to the widespread

use of CAI is economic, but new developments in display technology and com-

munications give a reasonable probability of cost-effective systems within this

decade. There is no special problem in having these systems available in the

home as well as at school. This would be aided by standardizing course writ-

ing languages. Again, we should try to stimulate competition by encouraging

the offering of courses in particular subjects independent of the schools.15.

The development of such a system is probably inevitable (unless it is for-

bidden by law) as soon as costs come down to the point where it is profitable

for time-sharing service bureaus to offer services to individuals. However, fa-

vorable policies will bring this about sooner and will make the effects better.

The main danger to be avoided is the creation of services of limited scope

that through some avoidable feature cannot be expanded to provide the ser-

vices mentioned here and many more.16 Another problem is to avoid mo-

nopolies; the intrinsic nature of the system permits any person who can

write computer programs to compete with large organizations in inventing

and offering imaginative services, but one can worry that the system might

develop commercially in some way that would prevent that. In general, we

should try to develop information services in such a way as will enhance the

individuality of its users.

Between us and the home information system lie a number of problems;

some in developing suitable low-cost terminals, some in programming tech-

nology of time-sharing, some in the economics and politics of communication

systems, and some in the attitude of the public and government towards

innovation. In the following sections we shall discuss these problems.

How we Get There from Here

  1. Consoles The quality and price of display consoles is rapidly improving. At present,

    one can add a display console with keyboard to our laboratory system for

    about $ 700, but to add another part on the system so that the number

    of consoles active at one time is increased by one costs about $ 2,500. A

    reasonable display console that can be located at the end of a telephone line

    now costs about $ 10,000. These consoles are adequate for any of the services

    15All these have happened

    16Minitel in France was such a service, and the promoters of set-top-boxes are trying

    for such limited devices. I think they’ll fail, and this is shown by the fact that companies

    like Ford are offering their employees PCs and not set top boxes.

    mentioned in the previous section, although for reading purposes, it would

    be desirable to be able to display more than 35 typed lines at a time.17

    In my opinion, the cost of an adequate display terminal that can be

    located at the end of a telephone line will be in the $ 500 to $ 1000 range

    by 1975 even without a market of the size of the potential home-terminal

    market. The business, engineering and science, and government markets will

    be large enough and price sensitive enough to bring this about.18

    Another contender as a terminal is the plasma panel, but the above esti-

    mates are based on CRT terminals with a mini-computer and an integrated

    circuit memory.19

  2. Communications In the United States, the facilities for digital communications are grow-

    ing rapidly but in a rather disorderly way because of the multiplicity of

    requirements of the different applications. Some applications such as credit

    verification require very low-cost short communications with turn-around

    times of seconds. Others require very low cost per bit but can stand delays

    of minutes and hence are candidates for low performance store and forward

    systems. The terminal systems require long holding times, short response

    times, and much higher transmission rates from the computer to the user

    than in the other direction.

    For the purposes of the home terminal, the speeds of transmission over

    present unconditioned voice-grade circuits are a bit too low for such appli-

    cations as reading. 1200 bits per second would take 20 sec to transmit a

    typed page and about 4 times that for a page of a dictionary. Eight times

    this rate is obtained over conditioned voice-grade lines, and this might be

    barely adequate. Perhaps a better bet is the transmission facility planned

    for the picturephone service now being introduced experimentally, but the

    cost of this service for long holding times is not yet determined. The most

    economical system might be a specially designed store and forward system

    configured to give fast turn-around for short messages.20

    Whether such a service will be made available depends on political as

    well as technical factors. For example, if on the basis of present plans, the

    17Remember that those numbers represent a larger fraction of a person’s income than

    a PC does today.

    18It didn’t happen that soon, because the terminals were too elaborate.

    19Plasma panels and the like are still an also-ran. The LCD panel didn’t exist then.

    20The Arpanet met this specification around that time, but its use was limited to labo-

    ratories supported by DoD. It gradually expanded till it became the Internet.

    digital communication market is divided by regulatory action among AT&T

    and its potential competitors, it might turn out that no one is obliged or

    even allowed to offer the service required for home terminals at a reasonable


  3. Computer Technology At present, computer technology can offer the services required for the

    home terminal at a reasonable cost, provided computer configurations are

    optimized for the purpose, provided reasonable load factors can be obtained,

    and provided there are reasonable economies of scale. Unfortunately, IBM

    computers are organized in such a way that time-sharing is very expensive

    because of their interrupt-structure, their expensive terminal multiplexors,

    and their dedication to the archaic half duplex method of communication.

    The other major computer manufacturers such as CDC, General Electric,

    and Univac are not in much better shape since they offer for time-sharing

    machines that were optimized for other purposes. Smaller companies like

    DEC are in a somewhat better position. However, none of these difficulties

    are permanent, and better organized computers may be expected once the

    factors in computer design that make for good cost-performance in time-

    sharing become clearer to the manufacturers.21

    The present magnetic disk storage units are a bit marginal in cost effec-

    tiveness for use with home terminals. Thus storage on the new IBM 3330

    disk would cost a user about $ 0.03 per month to store a typewritten page

    making storage of extensive personal files expensive and private copies of

    books at $ 5 to $ 10 per month prohibitively expensive. This would not be

    too expensive for national libraries, but it would be economically very diffi-

    cult to get enough readers to support the storage of books on magnetic disk

    files in the near future.

    Fortunately, much larger files are becoming available. The laser file made

    by Precision Instruments Inc.

    is claimed to store a trillion bits and costs

    $ 1,000,000. This comes to about $ 4 per book which is reasonable even

    for single copies. Mass production of such files will reduce the cost even


    21The archaic features of IBMs computers lasted much longer than I expected.

    22No-one, not even IBM, imagined how much that same old magnetic disk technology

    could be refined—mainly by IBM. This made the laser file an also-ran. It is now much

    cheaper to store a single copy of a book on your disk file than on your bookshelves. You

    still (2000 May) can’t get the books you want unless they are among the more than 11,000

    books in John Mark Ockerbloom’s catalog of free on-line books, which have been entered

  4. Computer Programming The basic technology of writing time-sharing technology is reasonably

    well-developed in that cost-effective systems have been written, but there is

    still a lot of chasing of willow-the-wisps, and quite bad time-sharing systems

    are often produced by otherwise competent firms. Before the programming

    required to offer the services mentioned in the first part of this paper can be

    accomplished, some further advances need to be made including at least the


    (1) the interactive and file reference aspects of programming languages

    and time-sharing systems need to be standardized so that an interactive

    system written in one system can be used in another that uses different

    hardware and a different time-sharing system. Without this it will be very

    expensive for new user services to get large markets unless some particular

    timesharing system gets a monopoly;23

    (2) a system needs to be developed for representing text in a computer

    that will include the full variety of alphabets, type fonts and character sizes

    and also be adaptable to diagrams, drawings and photographs. The consoles

    also have to be adapted to this variety of styles. This is an ultimate require-

    ment; much can be done with texts that are just regarded as sequences of

    latin letters;24

    (3) the biggest task, however, is the application programming itself.

  5. Commercial Organization From a social point of view, one of the attractive features of the provision

    of time-sharing services is that it is not a natural monopoly. Communication

    is cheap enough for teletype-based time-sharing so that with local multi-

    plexors, time-sharing bureaus can compete all over the United States.


    principal, it should be possible to have world wide competition. The ma-

    jor force that might tend to reduce competition is the exclusive possession

    of proprietary programs or files. Therefore, it is desirable to separate the

    ownership of programs performing services from the ownership of the service

    bureaus themselves and to encourage enough compatibility between different

    time-sharing systems so that the owner of a service program could provide

    it on a number of machines.

    It is also important that important files be

    accessible and modifiable with suitable protections by actions initiated on

    by various enthusiasts. The catalog is at http://digital.library.upenn.edu/books/. When

    I want to read such a book, I read it via Netscape rather than copy it to my own disk.

    23This is the situation today including Microsoft’s attempt to maintain a monopoly.

    24This still hasn’t happened in a uniform way. It’s coming. It’s coming.

    other machines than the one that maintains the file.25

  6. Needs for Research and Development The hardware required for home consoles will be too expensive for exten-

    sive systems for probably another 5 years. In the meantime, research and

    development should be undertaken in the following areas:

    (l) standarization of the interfaces of time-sharing systems and their lan-


    (2) experimentation with services. At present, it is very difficult to get

    support for development of generally useful services unless either it can be

    claimed that disaster will result from failure to support the activity or that

    the supporting organization will itself make a profit. This political fact is

    one of the reasons for the concentration on military technology in the recent


    (3) research aimed at devising ways of coordinating the great variety of

    time-sharing services into a mutually communicating network. Neither suf-

    ficient understanding nor sufficient political or commercial force is available

    to cause the development of timesharing services to proceed according to a

    unified plan. Nevertheless, computers are flexible enough so that originally

    incompatible systems can be made to communicate and use each other’s ser-

    vices. Experiments with the ARPA network that provides communication

    between US Government-sponsored research computers will provide useful


  7. Comments on the Conference In general, the conference showed a poor situation in the scientific and

    technological community and also the public affairs community regarding

    technology and the human future. There were a few technically competent

    but rather narrow surveys of the state and prospects of particular tool areas

    of technology. There was much random doom-saying and denunciation of

    currently fashionable whipping boys. There was a fair amount of opinion that

    certain things should not be done. There was an almost total lack imaginative

    discussion of the opportunities technology offers us to improve human life.

    This lack was especially notable in those individuals and organizations that

    25The prevalence of personal computers has accomplished the separation between own-

    ership of hardware and the development of programs.

    26It didn’t happen and isn’t happening.

    27In 1972 the Stanford AI Laboratory, with most of the work done by Martin Frost,

    built an experimental online news service based on the Associated Press news wire. We

    never attempted to expand it beyond the AI Lab computer. It lasted till 1989.

    are supposed to be professionally concerned with the matter. This essay

    represents a small effort to redress the balance.28

    28This was a particularly bad conference in the above respects, but conferences domi-

    nated by equally bad attitudes persist to the present day.