I looked in a mirror at reflection of the face covered with foam, and started having a shave. The special edge smoothly moved on skin. I inflated cheeks, pulled in lips, raised a chin and in general built unimaginable grimaces. This occupation so carried away me that I noticed not at once two more reflections in a mirror. Behind my back my good acquaintances — modern gnomes PITT and FITT soared in air. (PITT — is tremendous, and FITT — fantastic gnomes informants about secrets of equipment. From time to time they unexpectedly appear in my apartment. ) Both of them imitated my mines, pretended that too have a shave. But when I greeted them, they ceased to build grimaces, and PITT took a pack of edges which I just opened, and, considering it, told:
- We wanted to tell you something, but it is long history. Finish the game, and we will wait in the room.
I quickly stopped to have a shave and ran to the guests. They jumped on regiments and examined books.
- You already here? - I asked FITT.
- I am very glad you to see. But tell me with what you came?
We took seat and PITT began:
- It seemed to us that you at all didn't pay attention to one very interesting thing.
Telling it, he gave to me a hand with a pack of edges and showed the set of strips printed on packing and figures.
- You know, what is it?
- It seems, any designations, - I answered.
- Any designations! I don't think! The healthy guy, it seems, received any education, and only it can tell? It is characteristic feature of the goods packed in the most modern way, it is possible to tell, their computer label! - PITT was indignant.
It seems, on my person it was visible that I not so well understand about what there is a speech as FITT joined conversation with a type of the teacher who explains a difficult lesson to not so sensible pupil:
- You, probably, know that computers are used in all areas of our life. Them apply and in trade, for example, in management of big warehouses. They remember, what goods there are and in what quantity, do lists of the goods sent to shops and arriving from manufacturers, make lists of new orders, conduct financial calculations.
- I heard something about it, - I shy interfered.
- Here you see, - I continued FITT, - the computer can cope quite successfully with this work, but under one condition, certainly. Except input in his memory of appropriate programs of action, he should transfer somehow information on goods which he has to watch. All data are transferred to it in the form of the code in binary system — in the form of zero and units — via input-output devices: punchers of tapes or cards, readers, peculiar tape recorders which write down and read information from a magnetic tape, the device which remind typewriters, or rather teletypes. Their task — an encryption of information intended for the computer. It unusual — in the form of sets of holes in punched cards and gaps between them, magnetic traces on a tape, electric impulses, etc. The hole designates, for example, unit, and a place without a hole — zero. Computer devices of input-output are served, as a rule, by people. Certainly, it would be more convenient if the computer itself collected information by means of any sensors.
- Whether it means, what strips and figures to which you paid my attention, contain these data on the goods, intended for the computer? - I tried to show that something after all I understand.
It's true. Look here, - I told FITT and I developed the magic screen. On the screen there was the increased image similar to what was on a pack of edges. - It is the model marker, or — as we speak — the computer label drawn according to an applied so-called general commodity code. Sign this mysterious and difficult at first sight consists of the thin and thick strokes divided by wide and narrow strips. They conditionally designate a set from 12 figures. These figures, by the way, are written from below and sideways in "human" language — the Arab figures — except for one, the last which is intended for check. Extreme strips from the left and right side, and also in the middle are longer than the others and play a supporting role. They divide strokes into two groups and help the computer to learn where is left and where the right side of a code.
- Tell it that designate these numbers, - PITT hurried.
- The first, - FITT continued, - in our example — it is zero. He says that we deal with the consumer goods intended for sale in self-service shops. Five following figures — in a model marker are 1, 2, 3, 4 and 5 — serve for manufacturer coding. Five figures on the right side — in our case 6, 7, 8, 9 and 0 — own label of the goods. On this basis the computer can take from the memory such data, as an expiration date, the price and so forth.
- And the twelfth, control number about which you spoke? - I asked.
Serves for check, whether well the computer read a marker. This number is equal to addition (to frequency rate 10) the sums of numbers: the second, the third, the fifth, the ninth and the eleventh. If the addition calculated thus, differs from coded by means of dark strokes and light strips, the computer demands repeated reading all marker.
- In Western Europe similar markers are applied, but there are more than figures — 14, though a background always light, and strokes and figures dark — black, dark blue, dark green or dark brown.
- But how it manages to the computer to read signs of a shaped code? After all he doesn't see.
- You only are partly right, - told FITT. - For a long time designers think how to supply the computer with sight. They try to apply the devices similar to TV cameras and electronic schemes which analyze an arrangement of light and dark points on the screen to this purpose. But while it only experiments, and very labor-consuming and expensive.
Fortunately, to read signs quite simple device which is called as the light handle suffices. It called so because it is located in the plastic case similar to a pen.
Here in back part there is a tiny semiconductor laser. He creates a ray of light which through system of prisms and lenses gets to a narrow opening in forward part. This opening the light handle comes nearer to signs of a shaped code with which we want "to acquaint" the computer. Depending on, whether the beam on a light strip or on a dark stroke will get, the quantity of reflected light changes. The reflected beam again gets in the handle, and there goes on the photo diode. That, in turn, changes a light stream for the electric impulses clear to the computer.
- Tell, instead of whether it is dangerous to use the laser?
- It is the semiconductor laser of small power, to anybody it won't do harm. Light radiated by it one-color also differs from the surrounding. On the other hand, the photo diode is selected so that it reacted to that length of a light wave which radiates the laser. It excludes possibility of a mistake when reading the order. Look as accurately there is a service in shop which is supplied with such system.
I again looked at the screen: on it there was a buyer with a basket full of purchases, and approached to cash desk. The cashier dexterously moved the light handle on signs of a shaped code and in turn lowered goods in a plastic sack.
- Now the computer looks for in the memory of the price of separate goods and counts them. But there is more to come. The computer at any time can tell the director of shop as business with stocks is. Defines, on what goods there is the most great demand, what goods are already overdue.
- You picked up the bad movie, - PITT discontentedly told, - look, this buyer pays in ordinary money instead of giving a computer credit card. Then the computer connects to the computer in bank and automatically transfers the necessary sum from one account to another.
- Not all at once, - was told by FITT. - Today we will talk about a shaped code. To them designate packing of the most different goods: food, industrial, cosmetic; drugs, even newspapers, magazines and books. Here the striking example of that the computer became the device which million people in the different countries of the world use.
Such systems work and in other places, for example, in libraries. Earlier all data on books and readers were written out manually or on the typewriter on cardboard cards. Cards with a shaped code are now entered. They are used in catalogs of books and lists of readers. It allows to automate work of libraries. It is in passing possible to obtain any data on a condition of library, on interest of readers to some authors or problems. All these information the computer it is hardworking overworks and the result of the work shows according to the first requirement.
FITT for a minute reflected, and then unexpectedly declared:
- With pleasure would drink a glass very sweet to tea.
PITT joined this request.
I apologized before the guests that didn't think of it earlier, and went to kitchen. And when I took a tea pack from the shelf, saw on it... shaped a code which still didn't notice.