Developing
an operating system is one of the most complicated activities and favorite of
most of the computing hobbyists. For a hobby OS, its code is not directly
derived from the already existing Oss. Some entirely new concepts might also be included
in the OS development. It may also start from modeling an existing one. Whatever
the case maybe, the hobbyist is his own active developer. Application software might be developed
specifically for an OS or hardware. Therefore, when the application has to be
ported to some OS that may implement its required functionality differently,
the application might be required to be changed, adapted or maintained.
Types of Operating System
There
are many types of operating about which we shall discuss in this article.
1. Real time operating system:
- It is a multi –
tasking OS aimed at the execution of the applications that are real time.
-These operating systems work on scheduling algorithms written
exclusively for them.
- This is done so as to make them achieve a behavior
that is deterministic in nature.
- Their main objective is to give a quick
response to the events that is also predictable in nature.
- The design
which is implemented is event driven and employs the idea of time sharing and sometimes both.
- The system that is event driven switches
among the different tasks according to the priorities assigned to them.
- On
the other hand, the systems following the time sharing methodology
switch between the tasks based up on the clock interrupts.
2. Multi–user and single user operating
systems:
- In the multi–user operating systems the same computer system
can be accessed by multiple users at the same time.
- Systems that can be
classified under the multi–user systems are the internet servers and the
time sharing systems since using the time sharing principle they allow
multiple users to access the system.
- There are other types of operating
systems that allow only one user to execute a number of programs
simultaneously and are called the single – user operating systems.
3. Multi–tasking and single–tasking operating
systems:
- The operating systems that allow multiple programs to be executed
simultaneously (as per the human time scales) are termed as the multi –
tasking OS.
- In the single–taking OS, only one program can be run
at a time.
- Multi –taking can be done in the following two ways:
Ø Pre–emptive multi –tasking: The CPU time is sliced and each of the time slots are given to each of the
programs that are to be executed. This kind of multi–tasking is supported by
the operating systems such as Linux, AmigaOS and Solaris.
Ø Co–operative multi–tasking: Systems following this rely on
one process for giving time to the other processors but in a pre–defined
manner. This multi–tasking type was used by the MS windows 16 – bit version,
Mac OS preceding OS X.
There are
Oss that used to support both of these namely win9x and Windows NT.
4. Distributed operating system:
- This kind of OS
is used to manage a group of computers that are independent of each other
and makes them seem like one single system.
- This OS led to the development
of networked computers which could link to and communicated with one
another.
- These computers in turn paved way for distributed computing.
- They
carried out computations on more than one computer.
- Computers working in
cooperation with each other, together make up a distributed system.
5. Embedded Operating System:
It is used in embedded computer systems
such as in PDAs.
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