Main memory: ram and rom.

The main memory of a computer is also called the ‘immediate access store’, as distinct from any other storage memory available on disks. 1_______: RAM and ROM, both contained in electronic chips connected to the main board of the computer.

RAM stands for ‘Random-Access Memory’ and is the working area of the computer, that is, the basic location where the microprocessor stores the required information. It is called ‘random access’ because the processor can find information in any cell or memory address with equal speed instead of looking for the data in sequential order. 2_______, so it is lost when the machine is turned off. Therefore, if we want to use this information later on, we have to save it on a disk. When running an application, the microprocessor finds its location in the storage device (the floppy or hard disk) and transfers a temporary copy of the application to the RAM area. Consequently, 3_______ if we want to increase the performance of a computer, when several applications are open at the same time or when the document is very complex.

The RAM capacity can sometimes be expanded by adding extra chips. These are usually contained in Single In-line Memory Modules or SIMMs, which are installed in the motherboard of the computer.

We can designate a certain amount of RAM space as a cache in order to store information that an application uses repeatedly. A RAM cache may speed up our work, but it means that we need enough internal memory or a special cache card.

ROM is an acronym for ‘Read-only Memory’. Which implies that the processor can read and use the information stored in the ROM chip, but cannot put information into it. 4_______, including instructions and routines for the basic operations of the CPU. These instructions are used to start up the computer, to read the information from the keyboard, to send characters to the screen, etc. They cannot be changed and are not erased when the power is turned off. For this reason, the ROM section is also referred to as firmware.

(E.C.U.)

Упражнение 27.

a) Прочитайте текст:

Types of Memory

As mentioned previously, one of the most important characteristics of a computer is its capability of storing information in its memory long enough to process it. Not all computers have the same type of memory. In this section, three types of memory will be discussed: core memory, semiconductor memory (or chip), and bubble memory.

The memory of the first computers was made up of a kind of grid of fine vertical and horizontal wires. At each intersection where the wires crossed, there was a small ferrite ring called a core (hence the name ‘core memory’) which was capable of being either magnetized or demagnetized. Every intersection had its unique address; consequently, when an electric current was passed through the wires, the magnetized as well as unmagnetized cores were identified by their respective addresses. Each core represented a binary digit of either 0 or 1, depending on its state. Early computers had a capacity of around 80,000 bits; whereas now, it is not surprising to hear about computers with memory capacity of millions of bits. This has been made possible by the advent of transistors and by the advances in the manufacture of miniaturized circuitry. As a result, mainframes have been reduced in both size and cost. Throughout the 1950s, 1960s and up to the mid-1970s, core memory dominated the market, but it is now obsolete.

In the 1970s, there was a further development which revolutionized the computer field. This was the ability to etch thousands of integrated circuits onto a tiny piece (chip) of silicon, which is non-metallic element with semiconductor characteristics. Chips have thousands of identical circuits, each capable of storing one bit. Because of the very small size of the chip, and consequently, of the circuits etched on it, electrical signals do not have to travel far; hence, they are transmitted faster. Moreover, the size of the components containing the circuitry can be considerably reduced, a step which has led to the introduction of both minis and micros. As a result, computers have become smaller, faster, and cheaper. There is one problem with semiconductor memory, however: when power is removed, information in the memory is lost – unlike core memory, which is capable of retaining information during a power failure.

Another development in the field of computer memories is bubble memory. The concept consists of creating a thin film of metallic alloys over the memory board. When this film is magnetized, it produces magnetic bubbles, the presence or absence of which represents one bit of information. These bubbles are extremely tiny, about 0.1 micrometer in diameter. Therefore, a magnetic bubble memory can store information at a greater density than existing memories, which makes it suitable for micros. Bubble memories are not expensive, consume little power, are small in size, and are highly reliable. There is probably a lot more to learn about them, and research in this field continues.

(E. C. S.)

b) Просмотрите текст вновь и скажите, верны ли данные утверждения. Измените предложения, содержащие неправильную информацию так, чтобы они тоже стали верными.

1. The most important function of a computer is to hold information in its memory in order to process it.

2. Minicomputers, microcomputers, and mainframes all have the same kind of memory.

3. Semiconductor memory was developed before core memory and after bubble memory.

4. Core memory uses small metal rings which can be magnetized and unmagnetized.

5. The state of the core can be represented by either 0 or 1.

6. Early computer memories had less storage capacity than newer ones.

7. A transistor and a chip are the same kind of device.

8. The development of chips made it possible for minicomputers and microcomputers to be invented.

9. Bubble memory is smaller than a chip.

10. Bubble memory doesn’t have very many advantages.