As mentioned in the previous chapter, the Operating
System (OS) is the software that controls functionality and
provides lower-level routines for application programs. Most operating
systems provide functions to read and write data on files. It then
translates requests for operations on files into operations that the
disk controller can carry out. The operating system helps the computer
perform four basic operations, which include
input-process-output-storage. The following provides a description of
each function:
The most common way to input data into a computer is from the
keyboard. Processing data usually results in some kind of output, such as a
word processor file or a spreadsheet. The most common way to output
data is to send it to the computer monitor or to a printer.
Data storage is probably the most important of the four basic computer functions. The most common way to store a file is to save it to a hard drive. Hard drives can be thought of as very large file cabinets. An operating system will find a place on the hard drive, save the file, and remember its location. |
Opening a
web page, an
e-mail file, or a file that came
from a network server are also ways to input data. After the data has
been input, the computer can then process or crunch the
data. 
When a file is opened and the text is reformatted, the
computer is processing data.
Today, most computers have a connection to the Internet, making it
common to output the data to the Internet via e-mail or as a web page.