Page 27 - DCAP103_Principle of operating system

Principles of Operating Systems

Notes 1.7.2 What does a Driver do?

A driver is a specially written program which understands the operation of the device it
interfaces to, such as a printer, video card, sound card or CD ROM drive. It translates commands
from the operating system or user into commands understood by the component computer
part it interfaces with. It also translates responses from the component computer part back to
responses that can be understood by the operating system, application program, or user. The
below diagram gives a graphical depiction of the interfaces between the operating system and
the computer component.

Figure 1.5: Operating System Interfaces

1.7.3 Other Operating System Functions

The operating system provides for several other functions including:
• System tools (programs) used to monitor computer performance, debug problems,
or maintain parts of the system.
• A set of libraries or functions which programs may use to perform specific tasks
especially relating to interfacing with computer system components.
The operating system makes these interfacing functions along with its other functions operate
smoothly and these functions are mostly transparent to the user.
1.7.4 Operating System Concerns

As mentioned previously, an operating system is a computer program. Operating systems
are written by human programmers who make mistakes. Therefore there can be errors in the
code even though there may be some testing before the product is released. Some companies
have better software quality control and testing than others so you may notice varying levels
of quality from operating system to operating system. Errors in operating systems cause three
main types of problems:

• System crashes and instabilities: These can happen due to a software bug typically in the
operating system, although computer programs being run on the operating system can
make the system more unstable or may even crash the system by themselves. This varies
depending on the type of operating system. A system crash is the act of a system freezing
and becoming unresponsive which would cause the user to need to reboot.

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