2 Vocabulary

The processor, also called the CPU or central processing unit, is the brain of your computer. In PCs, it is built into a single chip - a small piece of silicon with a complex electrical circuit, called an integrated circuit - that executes instructions and coordinates the activities of all the other units.

Three typical parts are:

• the control unit, which examines instructions from memory and executes them;

• the arithmetic and logic unit (ALU), which performs arithmetic and logical operations;

• the registers, high-speed units of memory used to store and control data.

The speed of a processor is measured in gigahertz (GHz). Thus, a CPU running at 4 GHz can make about four thousand million calculations a second. An internal clock sends out signals at fixed intervals to measure and synchronize the flow of data.

The main circuit board is known as the motherboard. This contains the CPU, the memory chips, expansion slots and controllers for peripherals, connected by internal buses, or paths, that earn,' electronic signals. For example, the front side bus carries all data that passes from the CPU to other devices.

Expansion slots allow you to install expansion cards which provide extra functions, e.g. a video card or a modem. Laptops have PC cards, the size of a credit card, which add features like sound, memory and network capabilities.

EXERCISES

2.1 Match the numbers and letters.

1. The CPU processes data and

2. The control unit is the part of the CPU that

3. The arithmetic and logic unit is able to make(d)

4. The registers are high-speed storage(a)

a) areas within the CPU.

b) controls the way instructions are executed.

c) coordinates the other parts of the computer.

d) calculations: add, subtract, multiply and divide

2.2 Solve the clues and complete with the words.

1. Intel processors are used in many computers.

2. Special cards can be inserted into expansion slots.

3. A……… controls the timing within the PC by sending signals to synchronize its circuits and operations.

4 The processor speed is measured in megahertz.

5 …… carry signals between different parts of a PC.

6 Memory cards improve the computer's performance.

7 The main printed circuit board is called the motherboard.

2 .3 Read this product description and answer the questions below.

1. How fast is the CPU? 2.4GHz

2. Which term is used to describe the CPU data bus? - MHz

3. How much RAM does the computer have? - 1024 Mb

4. Can you add extra RAM chips? How many? – yes, I can. It can be expanded up to 4GB

3 Language work: relative clauses

HELP box Relative clause We can define people or things with a restrictive (defining) clause. The teacher who is responsible for the computer centre has just arrived. We use the relative pronoun 'who' because it refers to a person. We could also use 'that'. This is my friend whose PC broke down last week. We use whose to talk about possession. The microprocessor is a chip which processes the information provided by the software. We use the relative pronoun 'which' because it refers to a thing, not a person. We could also use 'that'. Security is something that worries me. We use that after indefinites (something, all, etc.) The computer we saw at the exhibition runs at 2.5 GHz. Relative pronouns can be left out when they are not the subject of the relative clause. Relative adverbs The relative pronoun can be replaced by relative adverbs of place and time. This is the office where he works. (at which) I'll never forget the day when I visited Silicon Valley. (on which) Emphasis with relatives We can emphasize an element with it is/was that.. Compare: John sent Sally an e-mail last night. It was John that/who sent Sally an e-mail last night. (not Paul) It was Sally that John sent an e-mail to last night. (not Mary) It was an e-mail that John sent Sally last night. (not a postcard) It was last night that John sent Sally an e-mail. (not this morning)