Vai al sito Cultura e società






















La rivoluzione informatica




















Cerca una parola nel portale | Ricerca avanzata | Indice di tutte le parole

Mappatura del portale | Ultimi aggiornamenti


















































































































Vannevar Bush

 Luglio 1945













































































“As We May Think” 




















“Come potremmo pensare”







































Testo originale inglese, strutturato, provvisto di titoli e sottotitoli

in Italiano ed evidenziazioni in rosso dei concetti chiave

per facilitarne la lettura anche veloce e la comprensione






































































































































[La fine della guerra







































Il futuro della scienza




















o, meglio,




















degli scienziati]





















































































































This has not been a scientist's

war; it has been a war in which

all have had a part.



The scientists, burying their old

professional competition in the

demand of a common cause,

have shared greatly and learned



It has been exhilarating to work

in effective partnership.


Now, for many, this appears to

be approaching an end.


What are the scientists to do




For the biologists, and

particularly for the medical

scientists, there can be little

indecision, for their war has

hardly required them to leave

the old paths.


Many indeed have been able to

carry on their war research in

their familiar peacetime



Their objectives remain much

the same.



It is the physicists who have

been thrown most violently off

stride, who have left academic

pursuits for the making of

strange destructive gadgets,

who have had to devise new

methods for their unanticipated



They have done their part on the

devices that made it possible to

turn back the enemy, have

worked in combined effort with

the physicists of our allies.


They have felt within themselves

the stir of achievement.


They have been part of a great



Now, as peace approaches, one

asks where they will find

objectives worthy of their best.  


















































































































































































































[Il progresso dell'umanità







































La limitata fruibilità della




















conoscenza collettiva]





















































































































Of what lasting benefit has been

man's use of science and of the

new instruments which his

research brought into existence?


First, they have increased his

control of his material



They have improved his food, his

clothing, his shelter; they have

increased his security and

released him partly from the

bondage of bare existence.


They have given him increased

knowledge of his own biological

processes so that he has had a

progressive freedom from

disease and an increased span of



They are illuminating the

interactions of his physiological

and psychological functions,

giving the promise of an

improved mental health.



Science has provided the

swiftest communication between

individuals; it has provided a

record of ideas and has enabled

man to manipulate and to make

extracts from that record so that

knowledge evolves and endures

throughout the life of a race

rather than that of an individual.



There is a growing mountain of



But there is increased evidence

that we are being bogged down

today as specialization extends.


The investigator is staggered by

the findings and conclusions of

thousands of other workers -

conclusions which he cannot find

time to grasp, much less to

remember, as they appear.


Yet specialization becomes

increasingly necessary for

progress, and the effort to bridge

between disciplines is

correspondingly superficial.


















































































































































































































[La gestione




















della conoscenza







































Metodi e strumenti




















ormai obsoleti]





















































































































Professionally our methods of

transmitting and reviewing the

results of research are

generations old and by now are

totally inadequate for their



If the aggregate time spent in

writing scholarly works and in

reading them could be evaluated,

the ratio between these amounts

of time might well be startling.


Those who conscientiously

attempt to keep abreast of

current thought, even in

restricted fields, by close and

continuous reading might well

shy away from an examination

calculated to show how much of

the previous month's efforts

could be produced on call.


Mendel's concept of the laws of

genetics was lost to the world

for a generation because his

publication did not reach the few

who were capable of grasping

and extending it; and this sort of

catastrophe is undoubtedly being

repeated all about us, as truly

significant attainments become

lost in the mass of the




The difficulty seems to be, not so

much that we publish unduly in

view of the extent and variety of

present day interests, but rather

that publication has been

extended far beyond our present

ability to make real use of the



The summation of human

experience is being expanded at

a prodigious rate, and the means

we use for threading through the

consequent maze to the

momentarily important item is

the same as was used in the

days of square-rigged ships.



But there are signs of a change

as new and powerful

instrumentalities come into use.


Photocells capable of seeing t

hings in a physical sense,

advanced photography which can

record what is seen or even what

is not, thermionic tubes capable

of controlling potent forces

under the guidance of less power

than a mosquito uses to vibrate

his wings, cathode ray tubes

rendering visible an occurrence

so brief that by comparison a

microsecond is a long time, relay

combinations which will carry

out involved sequences of

movements more reliably than

any human operator and

thousands of times as fast-there

are plenty of mechanical aids

with which to effect a

transformation in scientific



















































































































































































































[I calcolatori







































Due secoli persi ma




















la loro ora è arrivata]





















































































































Two centuries ago Leibnitz

invented a calculating machine

which embodied most of the

essential features of recent

keyboard devices, but it could

not then come into use.


The economics of the situation

were against it: the labor

involved in constructing it,

before the days of mass

production, exceeded the labor

to be saved by its use, since all

it could accomplish could be

duplicated by sufficient use of

pencil and paper.


Moreover, it would have been

subject to frequent breakdown,

so that it could not have been

depended upon; for at that time

and long after, complexity and

unreliability were synonymous.



Babbage, even with remarkably

generous support for his time,

could not produce his great

arithmetical machine.


His idea was sound enough, but

construction and maintenance

costs were then too heavy.


Had a Pharaoh been given

detailed and explicit designs of

an automobile, and had he

understood them completely, it

would have taxed the resources

of his kingdom to have fashioned

the thousands of parts for a

single car, and that car would

have broken down on the first

trip to Giza.



Machines with interchangeable

parts can now be constructed

with great economy of effort.


In spite of much complexity,

they perform reliably.


Witness the humble typewriter,

or the movie camera, or the



Electrical contacts have ceased to

stick when thoroughly



Note the automatic telephone

exchange, which has hundreds

of thousands of such contacts,

and yet is reliable.


A spider web of metal, sealed in

a thin glass container, a wire

heated to brilliant glow, in short,

the thermionic tube of radio sets,

is made by the hundred million,

tossed about in packages,

plugged into sockets - and it



Its gossamer parts, the precise

location and alignment involved

in its construction, would have

occupied a master craftsman of

the guild for months; now it is

built for thirty cents.


The world has arrived at an age

of cheap complex devices of

great reliability; and something

is bound to come of it.































































































































































































[La documentazione




















della ricerca]







































[La tendenza di sviluppo




















delle tecnologie]


























































[Fotografia, minicamera

e fotoprocessi a secco]


































































































A record if it is to be useful to

science, must be continuously

extended, it must be stored, and

above all it must be consulted.


Today we make the record

conventionally by writing and

photography, followed by

printing; but we also record on

film, on wax disks, and on

magnetic wires.


Even if utterly new recording

procedures do not appear, these

present ones are certainly in the

process of modification and




Certainly progress in

photography is not going to stop.


Faster material and lenses, more

automatic cameras, finer-grained

sensitive compounds to allow an

extension of the minicamera

idea, are all imminent.


Let us project this trend ahead

to a logical, if not inevitable,



The camera hound of the future

wears on his forehead a lump a

little larger than a walnut.


It takes pictures 3 millimeters

square, later to be projected or

enlarged, which after all involves

only a factor of 10 beyond

present practice.


The lens is of universal focus,

down to any distance

accommodated by the unaided

eye, simply because it is of short

focal length.


There is a built-in photocell on

the walnut such as we now have

on at least one camera, which

automatically adjusts exposure

for a wide range of illumination.


There is film in the walnut for

a hundred exposures, and the

spring for operating its shutter

and shifting its film is wound

once for all when the film clip is



It produces its result in full color.


It may well be stereoscopic, and

record with two spaced glass

eyes, for striking improvements

in stereoscopic technique are

just around the corner.



The cord which trips its shutter

may reach down a man's sleeve

within easy reach of his fingers.


A quick squeeze, and the picture

is taken.


On a pair of ordinary glasses is a

square of fine lines near the top

of one lens, where it is out of the

way of ordinary vision.


When an object appears in that

square, it is lined up for its



As the scientist of the future

moves about the laboratory or

the field, every time he looks at

something worthy of the record,

he trips the shutter and in it

goes, without even an audible



Is this all fantastic?


The only fantastic thing about it

is the idea of making as many

pictures as would result from its




Will there be dry photography?


It is already here in two forms.


When Brady made his Civil War

pictures, the plate had to be wet

at the time of exposure.


Now it has to be wet during

development instead.


In the future perhaps it need not

be wetted at all.


There have long been films

impregnated with diazo dyes

which form a picture without

development, so that it is already

there as soon as the camera has

been operated.


An exposure to ammonia gas

destroys the unexposed dye, and

the picture can then be taken out

into the light and examined.


The process is now slow, but

someone may speed it up, and it

has no grain difficulties such as

now keep photographic

researchers busy.


Often it would be advantageous

to be able to snap the camera

and to look at the picture
































































































































































































[Termocarta scansione di immagini

televisione e fotografia a distanza]


































































































Another process now in use

is also slow, and more or less



For fifty years impregnated

papers have been used which

turn dark at every point where

an electrical contact touches

them, by reason of the chemical

change thus produced in an

iodine compound included in the



They have been used to make

records, for a pointer moving

across them can leave a trail



If the electrical potential on the

pointer is varied as it moves,

the line becomes light or dark in

accordance with the potential.



This scheme is now used in

facsimile transmission.


The pointer draws a set of

closely spaced lines across the

paper one after another.


As it moves, its potential is

varied in accordance with a

varying current received over

wires from a distant station,

where these variations are

produced by a photocell which

is similarly scanning a picture.


At every instant the darkness of

the line being drawn is made

equal to the darkness of the

point on the picture being

observed by the photocell.


Thus, when the whole picture

has been covered, a replica

appears at the receiving end.



A scene itself can be just as well

looked over line by line by the

photocell in this way as can a

photograph of the scene.


This whole apparatus constitutes

a camera, with the added

feature, which can be dispensed

with if desired, of making its

picture at a distance.


It is slow, and the picture is poor

in detail.


Still, it does give another process

of dry photography, in which the

picture is finished as soon as it is




It would be a brave man who

would predict that such a

process will always remain

clumsy, slow, and faulty in



Television equipment today

transmits sixteen reasonably

good pictures a second, and it

involves only two essential

differences from the process

described above.


For one, the record is made by a

moving beam of electrons rather

than a moving pointer, for the

reason that an electron beam

can sweep across the picture

very rapidly indeed.


The other difference involves

merely the use of a screen which

glows momentarily when the

electrons hit, rather than a

chemically treated paper or film

which is permanently altered.


This speed is necessary in

television, for motion pictures

rather than stills are the object.



Use chemically treated film in

place of the glowing screen,

allow the apparatus to transmit

one picture only rather than a

succession, and a rapid camera

for dry photography results.


The treated film needs to be far

faster in action than present

examples, but it probably could



More serious is the objection

that this scheme would involve

putting the film inside a vacuum

chamber, for electron beams

behave normally only in such a

rarefied environment.


This difficulty could be avoided

by allowing the electron beam to

play on one side of a partition,

and by pressing the film against

the other side, if this partition

were such as to allow the

electrons to go through

perpendicular to its surface, and

to prevent them from spreading

out sideways.


Such partitions, in crude form,

could certainly be constructed,

and they will hardly hold up the

general development.































































































































































































[Microfilm, riproduzione

e massdistribuzione miniaturizzata

di documentazione cartacea]


































































































Like dry photography,

microphotography still has a long

way to go.


The basic scheme of reducing the

size of the record, and examining

it by projection rather than

directly, has possibilities too

great to be ignored.


The combination of optical

projection and photographic

reduction is already producing

some results in microfilm for

scholarly purposes, and the

potentialities are highly



Today, with microfilm,

reductions by a linear factor of

20 can be employed and still

produce full clarity when the

material is re-enlarged for



The limits are set by the

graininess of the film, the

excellence of the optical system,

and the efficiency of the light

sources employed.


All of these are rapidly




Assume a linear ratio of 100 for

future use.


Consider film of the same

thickness as paper, although

thinner film will certainly be



Even under these conditions

there would be a total factor of

10,000 between the bulk of the

ordinary record on books, and its

microfilm replica.


The Encyclopoedia Britannica

could be reduced to the volume

of a matchbox.


A library of a million volumes

could be compressed into one

end of a desk.



If the human race has produced

since the invention of movable

type a total record, in the form

of magazines, newspapers,

books, tracts, advertising blurbs,

correspondence, having a volume

corresponding to a billion books,

the whole affair, assembled and

compressed, could be lugged off

in a moving van.


Mere compression, of course, is

not enough; one needs not only

to make and store a record but

also be able to consult it, and this

aspect of the matter comes later.


Even the modern great library is

not generally consulted; it is

nibbled at by a few.



Compression is important,

however, when it comes to costs.


The material for the microfilm

Britannica would cost a nickel,

and it could be mailed anywhere

for a cent.


What would it cost to print a

million copies?


To print a sheet of newspaper,

in a large edition, costs a small

fraction of a cent.


The entire material of the

Britannica in reduced microfilm

form would go on a sheet eight

and one-half by eleven inches.


Once it is available, with the

photographic reproduction

methods of the future, duplicates

in large quantities could

probably be turned out for a cent

apiece beyond the cost of



The preparation of the original



That introduces the next aspect

of the subject.































































































































































































[Comandi vocali, riproduzione

- codificazione/decodificazione digitale -

di linguaggi naturali]