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Disk storage - Display console - Airlines .. Computers work

Disk storage

The computer system relies mainly on disk storage to store a huge number of features, because it is much less expensive than the main notebook, which usually contains semiconductors or magnetic rings to store information, but it is much slower. Although storage on a magnetic disk is more expensive than storage on magnetic tape, the night of information stored in any location on the disk does not take more than a tenth of a second, while obtaining information stored at the far end of the magnetic tape may take a few minutes or more.

The disks are collected in stacks around a central core, with a space of about a quarter centimeter between adjacent disks. Each stack may contain six disks, each about 35 cm in diameter. The discs rotate at 2400 rpm or more and the data is stored on both surfaces of each disc, except for the ends of the stack sometimes, in about two hundred circular magnetized ribs on each surface. The stack holds about twenty-five million characters that are read and written by a head.

(The disc stack consists of a number of cylinders that resemble music records, except that they have magnetized surfaces on which information is recorded.
The information is read and written by heads mounted on a comb-like mechanism that moves horizontally.)

(The display console consists of two main parts: a touch panel similar to a typewriter panel and a television screen on which the letters and numbers formed by an electron beam are displayed, which represents either the information entered into the computer via the touch panel or the computer's response to this input.)

Each surface is magnetized, and all heads are mounted on a comb-like mechanism that moves horizontally and radially between the center of the disk and its periphery. Data can be transferred to and from the disk at a rate of 156,000 characters per second once the head is in the appropriate position.

The disk stack is mounted on a rotating unit, some of which can hold one stack while others can hold eight stacks at once. The stack can be easily removed from its place and replaced with another stack.

Other types of disk stacks are also used, with larger storage capacities and fixed in their positions.

Display consoles are the easiest and most common means of communicating with the computer, and consist of a touch panel and a television screen that shows what is entering the computer via the touch panel and the computer's response to this input.

They can display between 200 and 1,000 characters on the screen at one time. The display console is controlled by a special unit that may control twenty consoles or less, none of which is more than thirty-five meters away from the control unit. The display console on the typewriter terminal is characterized by its speed and the ability to review the text displayed on the screen and modify or correct it before entering it into the computer, but it does not provide a permanent record of the text as the typewriter does.