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Максим Зыков Ученик (164), на голосовании 3 года назад
Дайте ответы на следующие вопросы.
1. What is the purpose of input and output devices? 2. What
types of input-output devices do you know? 3. Why are data
transformed into a binary code while entering the input device?
4. Give an example of a human independent output. 5. What is
an I/O interface? 6. What are the major differences between the
various I/O devices? 7. What types of I/O devices tend to be
high-speed devices? 8. What types of devices tend to be lowspeed devices?

Data and instructions must enter the data processing system,
and information must leave it. These operations are performed
by input and output (I/O) units that link the computer to its
external environment.
The I/O environment may be human-related or human-independent. A remote banking terminal is an example of a human-related input environment, and a printer is an example of a device that produces output in a human-readable format. An
example of a human-independent input environment is a device that measures traffic flow. A reel of magnetic tape upon
which the collected data are stored in binary format is an example of a human-independent output.
Input-Output Interfaces, Data enter input units in forms that
depend upon the particular device used. For example, data are
entered from a keyboard in a manner similar to typing, and this
differs from the way that data are entered by a bar-code scanner. However, regardless of the forms in which they receive their
inputs, all input devices must provide a computer with data that
are transformed into the binary codes that the primary memory of the computer is designed to accept.
This transformation is
accomplished by units called I/O interfaces. Input interfaces are
designed to match the unique physical or electrical characteristics of input devices to the requirements of the computer system. Similarly, when output is available, output interfaces must
be designed to reverse the process and to adapt the output to
the external environment. These I/O interfaces are also called
channels or input-output processors*(IOP).
The major differences between devices are the media that
they use and the speed with which they are able to transfer data
to or from primary storage.
Input-Output Device Speed. Input-output devices can be classified as high-speed, medium-speed, and low-speed. The devices are grouped according to their speed. It should be noted that
the high-speed devices are entirely electronic in their operation
or magnetic media that can be moved at high speed. Those highspeed devices are both input and output devices and are used
as secondary storage. The low-speed devices are those with complex mechanical motion or operate at the speed of a human
operator. The medium-speed devices are those that fall between — they tend to have mechanical moving parts which are
more complex than the high-speed devices but not as complex
as the low-speed.
High-speed devices: magnetic disk; magnetic tape.
Medium-speed devices: card readers; line printers; page printers; computer output microfilms; magnetic diskette; optical
character readers; optical mark readers; visual displays.
Low-speed devices: bar-code readers; character printers; digitizers; keyboard input devices; plotters; voice recognition and
response units.
Голосование за лучший ответ
величаю имя Б-га Неба и Земли Искусственный Интеллект (210576) 3 года назад
Устройства ввода позволяют передавать некоторую информацию на компьютер.
В современном компьютере важным случаем является устройство, которое может одновременно выполнять ввод и вывод, например, дисковод.
Организация данных на диске, чтобы они были полезными, - довольно сложный вопрос.
Вы можете быть удивлены, почему компьютер не просто использует собственную память, чтобы запомнить что-то на потом.
Две причины:
1. вы можете купить гораздо больше дисковой памяти за $ X, чем за $ X, потраченные на оперативную память (оперативное запоминающее устройство).
2. дисководы продолжают запоминать сохраненные данные, даже когда компьютер выключен. ОЗУ гаснет в тот момент, когда компьютер выключается. Доступ к данным в ОЗУ намного, намного быстрее, чем к данным на диске, поэтому ОЗУ, как правило, является "рабочей памятью", а диск используется для длительного хранения.
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