The computer memory:
It is a temporary storage area. It holds the data and instructions that the Central Processing Unit (CPU) needs. Before a program can be run, the program is loaded from some storage medium into the memory. This allows the CPU direct access to the program. Memory is a need for any computer.
A computer is usually an electrical device, which understands only electricity on and electricity off. This is expressed by using two symbols – 0 and 1 – which are called binarydigits or bits. Numbers and text characters are represented as codes, which are made up of combinations of 0s and 1s. Simple character codes are called ASCII (the American Standard Code for Information Interchange), and Unicode. In ASCII, eight bits – any combination of 0s and 1s – form one character or symbol. For example, the letter A is denoted by the code 01000001. The basic working unit of the computer's memory is a group of eight bits, which is called a byte.
The computer's memory consists of many millions of bytes. To make it easier, the unit K (for kilobytes) can be used to express memory capacity. One K equals 1,024. For example, 64K bytes of memory is the same as 65,536 (1,024 × 64 = 65,536) bytes. For larger memory capacities, the units mega and giga can be used. One megabyte of computer memory usually means 1024 kilobytes, which is 1,048,576 bytes, whereas one gigabyte means 1024 megabytes, which is 1,073,741,824 bytes. The size of the memory address that the computer uses limits the number of bytes it can handle.
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