Types of operating systems

Modern computer operating systems can be classified into three groups namely Batch
processing, Time sharing, and Real time operating systems.

· Batch processing operating system

In this environment a user submit tasks to a central unit where they are collected

into a batch, and subsequently placed on an input queue at the computer where

they will be run. In this case, the user has no interaction with the task during its

processing, and the computer’s response time is the turnaround time - the time

from submission of the job until execution is complete, and the results are ready

for return to the user.

· Time sharing operating systems

In this environment a computer provides computing services to several or many

users concurrently on-line. Here, the various users share the central processor, the

memory, and other resources of the computer system in a manner facilitated,

controlled, and monitored by the operating system. The user, in this environment,

has nearly full interaction with the program during its execution, and the

computer’s response time may be no more than a few seconds.

· Real time operating systems
These are designed to service those applications where response time is needed in
order to prevent error, misrepresentation or even disaster. Examples of real time
operating systems are those which handle airlines reservations, machine tool
control, and monitoring of a nuclear power stations. The systems, in this case, are
designed to enable interruptions; by external signals that require the immediate
attention of the computer system.