Information, machine words and instructions
1. Information is a set of marks or signs that have meaning. These consist of letters or numbers, digits or characters, typewriter signs, other kinds of signs, and so on. A computer reacts differently to different digits or characters, and reacts to them as units that have meaning. For example, information for an analog computer has to be in the form of distances, or rotations, or voltages, or other physical variables. And for a digital computer information has to be in the form of digits or numbers.
2. Any information may be represented by the binary system including two digits: one (1) and zero (0). Each 1 and 0 is a separate binary digit called a bit. A bit is the smallest part of information. Bits are typically grouped in units that are called bytes. A byte is the basic unit of information used in modern computers and consists of eight bits.
3. The bytes are handled usually in standard groups called machine words or just words. There are two basic types of information or words that can be put into a memory cell or location: words that are numerical quantitiesand words that are computer instructions. Regularly, an instruction to the machine is expressed as a word; and so the same set of characters may have meaning sometimes as a number, sometimes as an instruction. A speed of 96,000 characters per second is the same as a speed of 8,000 words per second. Most human beings could not take even 12-digit number per second.
4. Physically the set of bits is a set of arrangements of some physical equipment. One of the ways of storing information in a computer is storing by using a set of small magnetically polarized spots on a magnetic surface.
5. The computer is told what operations to perform by means of instructions. An instruction is a command to the computer. It consists of a verb (an operational code) and a noun (an operand). For example, if the computer is instructed "Add 365 the number of times (pa3) stated in the register R, and if the register R stores the code for number 3, then the computer will perform that operation three times. An instruction word looks like a number, and there is no way to tell from the word itself whether it is a quantity or an instruction. The computer must be told exactly which address contains an instruction and which contains a quantity.
6. An address is the name of particular memory location or cell. Each memory location (word or byte) has its own unique address or number just like a post office box. For example, if the computer contains 100 memory cells, their respective addresses might be the numbers from 1 to 100 (or 0 through 99). And instead of saying A word is in a memory cell", the computer personnel say, "The contents of an address is a word."
7. Reasonable operations are mathematical and logical. Mathematical operations include arithmetic and algebraic operations. Arithmetic operations are addition, subtraction, multiplication, division, taking a square root, etc.; and algebraic operations are called raising to a power as well as differentiating and integrating.
8. Logical operations include comparing, selecting, sorting, matching, etc. These are operations which may be performed either on numbers, or on expressions consisted of letters such as ordinary words. A very important logical operation performed by a computer is determining, i.e., which of two operations is to be performed next.
III. Language
Ex. 8 Find in the text derivatives of the following words containing suffixes: - al, -tion, -er, - able, - ment. State to what part of speech each word belongs, translate them into Russian. Use the table on page 102-104.
To inform, to locate, to arrange, an operation, a reason, logic, to operate.
Ex. 9 Match word and word combinations in column A with those in column B:
| A | B | ||
| 1. | numerical measurements by using physical | 1. | Фізичне обладнання |
| 2. | 2. | Швидкість за секунду | |
| analogs | |||
| 3. | the binary system | 3. | Числові величини |
| 4. | any information | 4. | Числові виміри |
| 5. | other physical variables | 5. | Дволична система |
| 6. | numerical quantities | 6. | Будь яка інформація |
| 7. | a speed per second | 7. | Один із способів |
| 8. | physical equipment | 8. | Особлива ячейка пам’яті |
| 9. | one of the ways | 9. | Використовуючи фізичні аналоги |
| 10. | a particular memory cell | 10. | Інщі фізичні змінні. |
Ex. 10 Make the sentences complete using the information from the text .:
1. Information is a set of marks or signs that ... .
2. Reasonable operations are ... .
3. Logical operations include ....
4. A very important logical operation is ....
5. Physically the set of bits is a set of arrangements of some... .
6. Determining means which of two operations is to be performed ...
7. The computer must be told exactly which address contains ... and which contains ... .
8. The computer is told what operations to perform by means of... .
9. Any information may be represented by the binary system including two digits: ,.. and .. .
10. A bit is the smallest part of ... .
Ex. 11 Find in the text definitions to the following terms, put them down and memorize:
1. Information
2. Reasonable operations.
3. Mathematical operations.
4. A byte.
5. A bit.
IV. Comprehension.