00100	                    THE HOME INFORMATION TERMINAL
00200	
00300	                          by John McCarthy
00400	
00500		Visionaries have often proposed that homes be  equipped  with
00600	information  terminals each consisting of a typewriter keyboard and a
00700	screen capable of displaying one or more pages of print and pictures.
00800	The  terminal  is  to  be  connected  by  the  telephone  system to a
00900	time-shared computer which in turn has access to files containing all
01000	books,  magazines,  newspapers,  catalogs,  airline  schedules,  much
01100	additional  public  information  not  now  kept,  and  various  files
01200	personal to the user.
01300	
01400		Through  the  terminal  the  user  can get any information he
01500	wants,  can  buy  and  sell,  could  communicate  with  persons   and
01600	institutions,  and process information in other useful ways.   Such a
01700	system has never come about because it costs too much, but with  each
01800	advance  in  technology,  it becomes more feasible.  I think that the
01900	technology of computers,  time-sharing,  terminals,  and  application
02000	programming  has  advanced to the point where realistic estimates are
02100	possible of the remaining advances necessary to  make  home  consoles
02200	feasible  and useful.  In this paper, I shall discuss the uses of the
02300	home terminal, some potential beneficial effects on society, estimate
02400	how  far  we are from a system people will pay for, and advocate some
02500	pilot projects, some  standardization  efforts,  and  some  laws  and
02600	regulations to prevent monopoly and secure adequate competition.
02700	
02800		We  can  start  with ordinary reading.  To get a newspaper or
02900	book, I type its name or number and the first page appears.  The most
03000	obvious benefits are:
03100	
03200		1. I can get any document instantly.
03300	
03400		2.  My  house  isn't  full  of  paper to be sorted and put on
03500	shelves and dusted or put in the trash.  Trees aren't cut  down,  and
03600	air pollution doesn't result from burning the stuff.
03700	
03800	Some immediately apparent disadvantages are:
03900	
04000		1. The expense.  I'll deal with this later.
04100	
04200		2. I can't read in bed.  The book size portable terminal will
04300	come later.  A household may require several terminals or perhaps  we
04400	may  have  to  compromise  with  sin and provide a hard copy terminal
04500	after all.
04600	
04700		There are two other immediate negative reactions:
04800	
04900		1.   The average citizen is a TV fan and doesn't read anyway.
05000	In the first place, our system doesn't need so many subscribers to be
05100	economical.   Secondly, after I have  described  all  the  bells  and
05200	whistles,  you will see that even the TV fan will be tempted, and you
05300	- oh socially conscious reader - may even want  to  coerce  him  into
05400	buying one or coerce the government into giving him one for free.
05500	
05600		2. How can you think of one more convenience and comfort when
05700	the world will come to an end in ten years unless menaces A, B, and C
05800	are  dealt  with  immediately.  In the first place, I don't think the
05900	world is about to come to an end or even that it  is  getting  worse,
06000	and we Americans like new gadgets.  In the second place, you will see
06100	that the new information system will make the public more  responsive
06200	to  the  careful  reasoning  of  you good guys and more immune to the
06300	blatant propaganda of those bad guys.
06400	
06500		In order to see the effects of the  new  information  system,
06600	suppose  that all book and newspaper information were so distributed.
06700	What changes would occur?
06800	
06900		At present, a newspaper or a book is a package produced by  a
07000	large  organization.       In our new system, the physical production
07100	disappears, allowing a much smaller organization to put out the  same
07200	packages  of  text  and pictures.  Moreover, the user does not face a
07300	one shot decision to buy Life or Look.  He will be able to  read  the
07400	"cover"  or  table of contents of each, read such items as strike his
07500	fancy, and the system will bill him  for  what  he  reads  from  each
07600	source.   In fact, since the cost of keeping a file of information in
07700	the computer and making it publicly available will be small,  even  a
07800	high  school  student  could  compete with the New Yorker if he could
07900	write well enough and if word  of  mouth  and  mention  by  reviewers
08000	brought him to public attention.      What, then, is a publication in
08100	the new information system?
08200	
08300		A publication is an organization that  puts  out  a  list  of
08400	material  it  has edited and recommends to its readers.  It helps its
08500	authors produce material that it thinks will suit the readers, and it
08600	has a financial arrangement with them about splitting the proceeds.
08700	
08800		There  can  be  a  wide  variety of publications of different
08900	standards of writing and editing and different budgets  for  carrying
09000	out  these  activities.  However, they will all be equally accessible
09100	to all readers, and the only justification for an expensive editorial
09200	organization will be that it can produce a more popular package.  The
09300	price of reading a package can be set by the publishers.
09400	
09500		A reader may feel that he  needs  help  in  finding  his  way
09600	through  the totality of literature available to him.  Various people
09700	will be eager to make a living by providing it.      A  bookstore  or
09800	library  is  a  program  that  when  called  shows  the  "covers"  of
09900	publications.    Reviewers will produce lists for him and make  money
10000	when  he  reads  their  lists  or  by  kickbacks from the publishers.
10100	"Reading advisers" under some catchier name will  offer  to  generate
10200	lists just for him according to a profile of his interests.
10300	
10400		Advertising  in  the sense of something that can force itself
10500	on the attention of a reader will disappear because it  will  be  too
10600	easy  to  read  via  a program that screens out undesirable material.
10700	However, people will still want to know what is  for  sale  and  will
10800	still  want  to  see the seller's story about why they should buy it.
10900	Probably, Life will still be able to get money from advertisers; many
11000	people  will still want to know what is advertised in Life, but those
11100	who don't want to know will be able to avoid it automatically.
11200	
11300		Another effect is the possibility of  frequent  revisions  of
11400	articles  and  books.    An author can take into account new facts or
11500	other  people's  criticisms,  and  the  revision  will  take   effect
11600	immediately.      This  raises  1984ish  possibilities, so it must be
11700	provided that old versions remain available.  Those who  suspect  the
11800	whole system will keep their own copies of favorite material in their
11900	private files, on microfilm, or even on paper.
12000	
12100		Public controversy can be carried out more expeditiously than
12200	at  present.  If I read something that seems controversial, I can ask
12300	the system if anyone has filed a reply.     This,  together  with  an
12400	author's  ability  to revise his original statement, will lead people
12500	to converge on considered positions more quickly than at present even
12600	if they do not come to actual agreement.
12700	
12800		Famous  authors  will not need publishers because their loyal
12900	readers will have the system find their stuff automatically.
13000	
13100		To summarize:      the new information  system  will  promote
13200	intellectual  competition by reducing the price of entry, will permit
13300	readers to be selective, and will allow authors  to  revise  material
13400	until  they  are satisfied that it withstands criticism as well as it
13500	ever will.  This should make intellectual life more interesting.
13600	
13700		The financial  aspect  of  writing  would  presumably  be  as
13800	follows:     a  piece of written material has a price for reading it.
13900	(This price may be zero for amateur  writing,  political  propaganda,
14000	advertising,  and  for scientific journals).  The reader's account is
14100	debited  and  the  account  to  which   the   material   belongs   is
14200	automatically credited.  The reader will have the system balk at what
14300	he considers overpriced material.
14400	
14500		The new information system will have  a  profound  effect  on
14600	buying  and  selling.      Sellers of movies, groceries, automobiles,
14700	plumbing services and cures for baldness will find it advantageous to
14800	list  their  wares  in  the  information system together with current
14900	prices and availability.    The user can place an order  through  the
15000	system as he can by telephone, but he can do much more:
15100	
15200		1.    He can call on someone's program to scan the sellers of
15300	sports cars and propose what it considers the best deal. This program
15400	might even negotiate with programs representing the sellers.
15500	
15600		2.    He  can  tell  the  system whether last year's cure for
15700	baldness worked and a get a summary of  the  opinions  of  those  who
15800	bothered  to record their opinions of the cure he contemplates trying
15900	now.
16000	
16100		3.     He can  make  an  airplane  or  hotel  reservation  by
16200	interacting  with  a program the airline or hotel reservation company
16300	has written to tell him what is available. He  need  not  suffer  the
16400	delays  you  now get when you call an airline or travel agent at peak
16500	hours.
16600	
16700		4. Individual design and construction services can be offered
16800	through the system although this requires the development of computer
16900	controlled manufacturing techniques for various types of article. The
17000	idea  is  that  automated  design  programs  can  produce designs for
17100	articles meeting individual specifications.  Either by himself or  in
17200	consultation  with  an  expert, an individual would use the system to
17300	produce a design and display how it would look and  possibly  how  it
17400	would  perform.    Candidates for individual design include clothing,
17500	furniture, boats, electronic equipment, houses, and even cars.    The
17600	system  would  then  produce the instructions for controlling machine
17700	tools, fabric cutters, and also printed  instructions  for  the  hand
17800	parts  of  the  operation.  In general, it should be possible to make
17900	single objects  at  little  more  cost  than  present  mass  produced
18000	objects.     In some cases, there would even be savings, because mass
18100	production  requires  estimates  of  demand  that  are  often   wrong
18200	resulting  in  inventories that are expensive to sell or even have to
18300	be sold at a loss; the cost of this is made up by a general  increase
18400	in prices.
18500	
18600		There  are  many  more  useful  services  that can be offered
18700	through the new information system and again the system is  conducive
18800	to  competition.     Writing and storing a program and announcing its
18900	availability can be a very low capital operation, and the system  can
19000	collect whatever price has been set for its use.
19100	
19200		We could go on listing services that would come to be offered
19300	in a fully developed system, but now we shall list some  services  to
19400	smaller  groups  of  users that are cheaper to provide and which will
19500	help get the system started.
19600	
19700		1. Calculation  and  facilities  for  writing,  running,  and
19800	debugging  computer  programs.      This doesn't interest the general
19900	public much, but it is the present bread  and  butter  of  the  time-
20000	sharing  service  bureaus  that  will  grow  into the new information
20100	system.  At present, these service bureaus offer very convenient  way
20200	of  doing  small  scientific and engineering calculations, but do not
20300	offer reasonable prices for big computations, and are only  beginning
20400	to offer useful services to business firms.
20500	
20600		2.     Editing.      Anyone who writes (writers, journalists,
20700	scientists, advertising men, engineers  and  students)  will  benefit
20800	from  using  an editor program.  It allows easy revision, can be made
20900	to  check  spelling,  grammar,  and  punctuation,  and  will  produce
21000	justified or other forms of elegant output and also indexes.
21100	
21200		3.  Filing.  Keeping personal files in the computer has great
21300	advantages once documents  can  be  entered  without  retyping  them,
21400	either because they have been prepared in a computer readable form or
21500	because a suitable page reader is available.        Namely,  one  can
21600	retrieve  any  document  on  the basis of its characteristics without
21700	having taken the trouble to file it properly in the first place.
21800	
21900		4. Education.  Computer aided instruction (CAI) has  advanced
22000	to  the point that a number of courses or aids to traditional courses
22100	have been developed and have been shown to be useful.       The  main
22200	obstacle   to  the  widespread  use  of  CAI  is  economic,  but  new
22300	developments  in  display  technology  and  communications   give   a
22400	reasonable  probability of cost-effective systems within this decade.
22500	There is no special problem in having these systems available in  the
22600	home  as  well  as  at  school.  This would be aided by standardizing
22700	course writing languages.      Again,  we  should  try  to  stimulate
22800	competition  by  encouraging  the  offering  of courses in particular
22900	subjects independent of the schools.
23000	
23100		The development of  such  a  system  is  probably  inevitable
23200	(unless  it  is  forbidden  by law) as soon as costs come down to the
23300	point where it is profitable  for  time-sharing  service  bureaus  to
23400	offer  services  to  individuals.   However,  favorable policies will
23500	bring this about sooner and will make the effects better.
23600	
23700		The main danger to be avoided is the creation of services  of
23800	limited  scope that through some avoidable feature cannot be expanded
23900	to provide the services mentioned here and  many  more.       Another
24000	problem  is  to  avoid monopolies; the intrinsic nature of the system
24100	permits any person who can write computer programs  to  compete  with
24200	large  organizations  in inventing and offering imaginative services,
24300	but one can worry that the system might develop commercially in  some
24400	way  that  would  prevent that.  In general, we should try to develop
24500	information services in such a way as will enhance the  individuality
24600	of its users.
24700	
24800		Between  us  and  the home information system lie a number of
24900	problems, some in developing suitable low  cost  terminals,  some  in
25000	programming  technology  of  time-sharing,  some in the economics and
25100	politics of communication systems, and some in the  attitude  of  the
25200	public  and government towards innovation.  In the following sections
25300	we shall discuss these problems.
25400	
25500	
25600	How we get there from here.
25700	
25800	1. Consoles.
25900	
26000		The   quality  and  price  of  display  consoles  is  rapidly
26100	improving. At present, one can add a display console with keyboard to
26200	our  laboratory system for about $700, but to add another port on the
26300	system so that the number of consoles active at one time is increased
26400	by  one  costs about $2500.  A reasonable display console that can be
26500	located at the end of a telephone line now costs about $10,000. These
26600	consoles  are  adequate  for  any  of  the  services mentioned in the
26700	previous  section,  although  for  reading  purposes,  it  would   be
26800	desirable to be able to display more than 35 typed lines at a time.
26900	
27000		In  my opinion, the cost of an adequate display terminal that
27100	can be located at the end of a telephone line will be in the $500  to
27200	$1000  range  by  1975  even  without  a  market  of  the size of the
27300	potential home terminal  market.     The  business,  engineering  and
27400	science,  and  government  markets  will  be  large  enough and price
27500	sensitive enough to bring this about.
27600	
27700		Another contender as a terminal is the plasma panel, but  the
27800	above  estimates  are based on CRT terminals with a mini-computer and
27900	an integrated circuit memory.
28000	
28100	
28200	2. Communications.
28300	
28400		In   the   United   States,   the   facilities   for  digital
28500	communications are growing rapidly but in  a  rather  disorderly  way
28600	because   of  the  multiplicity  of  requirements  of  the  different
28700	applications.   Some applications such as credit verification require
28800	very low cost short communications with turn around times of seconds.
28900	Others require very low cost per bit but can stand delays of  minutes
29000	and  hence  are  candidates  for  low  performance  store and forward
29100	systems.   The terminal systems require  long  holding  times,  short
29200	response  times, and much higher transmission rates from the computer
29300	to the user than in the other direction.
29400	
29500		For  the  purposes  of  the  home  terminal,  the  speeds  of
29600	transmission  over  present  unconditioned voice grade circuits are a
29700	bit too low for such applications as reading.  1200 bits  per  second
29800	would  take  20 seconds to transmit a typed page and about four times
29900	that for a page of a dictionary.  Eight times this rate  is  obtained
30000	over  conditioned  voice  grade  lines,  and  this  might  be  barely
30100	adequate.   Perhaps a better bet is the transmission facility planned
30200	for the Picturephone service now being introduced experimentally, but
30300	the  cost  of  this  service  for  long  holding  times  is  not  yet
30400	determined.  The most economical system might be a specially designed
30500	store and forward system configured to  give  fast  turn  around  for
30600	short messages.
30700	
30800		Whether  such  a  service  will  be made available depends on
30900	political as well as technical factors.  For example, if on the basis
31000	of  present  plans,  the  digital  communication market is divided by
31100	regulatory action among AT&T and its potential competitors, it  might
31200	turn  out that no-one is obliged or even allowed to offer the service
31300	required for home terminals at a reasonable cost.
31400	
31500	
31600	3. Computer technology.
31700	
31800		At  present,  computer  technology  can  offer  the  services
31900	required for  the  home  terminal  at  a  reasonable  cost,  provided
32000	computer  configurations  are  optimized  for  the  purpose, provided
32100	reasonable load factors can  be  obtained,  and  provided  there  are
32200	reasonable  economies  of  scale.    Unfortunately, IBM computers are
32300	organized in such a way that time sharing is very  expensive  because
32400	of  their interrupt structure, their expensive terminal multiplexors,
32500	and  their  dedication  to  the  archaic  half   duplex   method   of
32600	communication.   The  other major computer manufacturers such as CDC,
32700	General Electric, and Univac are not in much better shape since  they
32800	offer  for  time  sharing,  machines  that  were  optimized for other
32900	purposes.   Smaller companies like  DEC  are  in  a  somewhat  better
33000	position.    However,  none  of these difficulties are permanent, and
33100	better organized computers  may  be  expected  once  the  factors  in
33200	computer  design  that make for good cost-performance in time sharing
33300	become clearer to the manufacturers.
33400	
33500		The present magnetic disk storage units are a bit marginal in
33600	cost  effectiveness for use with home terminals.  Thus storage on the
33700	new IBM 3330 disk would cost a user about $.03 per month to  store  a
33800	typewritten page making storage of extensive personal files expensive
33900	and private copies of books  at  $5  to$10  per  month  prohibitively
34000	expensive.    This would not be too expensive for national libraries,
34100	but it would be economically very difficult to get enough readers  to
34200	support  the  storage  of  books  on  magnetic disk files in the near
34300	future.
34400	
34500		Fortunately, much larger files are becoming available.    The
34600	laser  file  made by Precision Instruments Inc. is claimed to store a
34700	trillion bits and costs $1,000,000.  This comes to about $4 per  book
34800	which  is reasonable even for single copies.  Mass production of such
34900	files will reduce the cost even further.
35000	
35100	
35200	4. Computer programming.
35300	
35400		The  basic  technology  of writing time sharing technology is
35500	reasonably well developed in that cost effective  systems  have  been
35600	written,  but there is still a lot of chasing of willow-the-wisps and
35700	quite bad  time-sharing  systems  are  often  produced  by  otherwise
35800	competent  firms.     Before  the  programming  required to offer the
35900	services  mentioned  in  the  first  part  of  this  paper   can   be
36000	accomplished some further advances need to be made including at least
36100	the following:
36200	
36300		1.  The interactive and file reference aspects of programming
36400	languages and time sharing systems need to be standardized so that an
36500	interactive system written in one system can be used in another  that
36600	uses  different hardware and a different time sharing system. Without
36700	this it will be very expensive for new user  services  to  get  large
36800	markets unless some particular time sharing system gets a monopoly.
36900	
37000		2.  A system needs to be developed for representing text in a
37100	computer that will include the full variety of alphabets, type  fonts
37200	and  character  sizes and also be adaptable to diagrams, drawings and
37300	photographs.  The consoles also have to be adapted to this variety of
37400	styles.  This is an ultimate requirement; much can be done with texts
37500	that are just regarded as sequences of latin letters.
37600	
37700		3.  The biggest task, however, is the application programming
37800	itself.
37900	
38000	
38100	5. Commercial organization.
38200	
38300		From a social point of view, one of the  attractive  features
38400	of the provision of time-sharing services is that it is not a natural
38500	monopoly.      Communication  is  cheap  enough  for  teletype  based
38600	time-sharing  so  that  with local multiplexors, time-sharing bureaus
38700	can compete all over the United States.  In principal, it  should  be
38800	possible  to have world wide competition.  The major force that might
38900	tend to reduce competition is the exclusive possession of proprietary
39000	programs  or  files.    Therefore,  it  is  desirable to separate the
39100	ownership of programs performing services from the ownership  of  the
39200	service  bureaus  themselves  and  to  encourage enough compatibility
39300	between different time-sharing systems so that the owner of a service
39400	program  could  provide  it  on  a  number  of machines.   It is also
39500	important that important files  be  accessible  and  modifiable  with
39600	suitable  protections by actions initiated on other machines than the
39700	one that maintains the file.
39800	
39900	
40000	6. Needs for research and development.
40100	
40200		The hardware required for home consoles will be too expensive
40300	for extensive systems for  probably  another  five  years.    In  the
40400	meantime,  research  and  development  should  be  undertaken  in the
40500	following areas:
40600	
40700		1.  Standardization of the interfaces of time-sharing systems
40800	and their languages.
40900	
41000		2.   Experimentation  with services.   At present, it is very
41100	difficult to get support for development of generally useful services
41200	unless  either  it  can  be  claimed  that  disaster will result from
41300	failure to support the activity or that the  supporting  organization
41400	will itself make a profit.  This political fact is one of the reasons
41500	for the concentration on military technology in the recent past.
41600	
41700		3. Research aimed at devising ways of co-ordinating the great
41800	variety  of  time-sharing  services  into  a  mutually  communicating
41900	network.    Neither sufficient understanding nor sufficient political
42000	or  commercial  force  is  available  to  cause  the  development  of
42100	time-sharing  services  to  proceed  according  to  a  unified  plan.
42200	Nevertheless,  computers  are  flexible  enough  so  that  originally
42300	incompatible systems can be made to communicate and use each  other's
42400	services.      Experiments   with  the  ARPA  network  that  provides
42500	communication between U.S.  Government sponsored  research  computers
42600	will provide useful information.
42700	
42800	
42900	7. Comments on the conference.
43000	
43100		In general, the conference showed a  poor  situation  in  the
43200	scientific  and  technological  community and also the public affairs
43300	community regarding technology and the human future.   There  were  a
43400	few  technically competent but rather narrow surveys of the state and
43500	prospects of particular tool areas of technology.    There  was  much
43600	random doom-saying and denunciation of currently fashionable whipping
43700	boys.   There was a fair amount of opinion that certain things should
43800	not  be  done.     There  was  an  almost  total  lack of imaginative
43900	discussion of the opportunities technology offers us to improve human
44000	life.  This  lack  was  especially  notable  in those individuals and
44100	organizations that are supposed to be professionally  concerned  with
44200	the matter.
44300	
44400		This essay is part of an effort to correct the imbalance.