Рубрика:
43
command for loading a program or file. Icons or small graphic images that can be
selected with a mouse or other pointing device represent programs, functions, and files.
NOTES:
1
rewiring – перепрошивать;
2
followed the same pattern – следовали тому же образцу
Text 3 (D). Part of Computer System
In order to use computers effectively to solve problems computer systems are
devised. Computer systems may be discussed in two parts.
The first part is hardware – the physical, electronic, and electromechanical
devices that are thought of and recognized as “computers”. The hardware consists
of the Central Processing Unit (CPU), input devices and output devices. The CPU
is made up of a processor and a main memory, or main store. The processor
carries out, or executes, instructions in the program. The main memory stores
input data and the program needed by the processor. The main memory also holds
output data, or the results of processing.
Input devices are used to provide data for the CPU. The keyboard is a common data
input device. By using a keyboard, a user can enter data directly into the computer
system. Data is sometimes entered on cards or it is often input from a mass storage
device, such as magnetic tape or magnetic disk. A mass storage device has a much larger
capacity than main memory. That is, it can store more data. The tapes or disks are read
by an input device called a tape drive or a disk drive.
Output devices receive data from the CPU. The Visual Display Unit (VDU) and
printer are common output devices. The VDU is similar to a TV screen. The printer
produces printed output on paper. Both the VDU and printer present output data for
immediate use. Sometimes, the output data is transmitted along a telephone line to
another computer. Output data can also be stored for future use on a mass storage
device, such as magnetic tapes or disks.
Input and output devices as well as mass storage devices are collectively
called peripherals.
The second part is software – programs that control and coordinate the
activities of the computer hardware and that direct data processing.
For the computer system to operate, computer programs are required. A computer
program is a set of instructions for the CPU. These instructions tell the CPU where to
find the input data in the system. The CPU is also instructed how to process the data and
where to put the results. Programs are not hardware, as they have no electrical or
mechanical components. They can be easily changed according to the user’s needs.
Страницы
- « первая
- ‹ предыдущая
- …
- 43
- 44
- 45
- 46
- 47
- …
- следующая ›
- последняя »
