OPERATING SYSTEM, Types of OPERATING SYSTEM
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OPERATING SYSTEM
An operating system is defined as an interface (or bridge)
between the user of computer and the computer hardware. An operating creates
such a friendly environment for the user in which the computer is used
effectively and efficiently. An operating system performs a number
inter-process communication, protection and security.
Types of OPERATING
SYSTEM
BATCH PROCESSING
OPERATING SYSTEM
Batch
processing means executing a series of jobs all at one time. The jobs with
similar requirements are batched together and run through the computer as a
group. The term originated in the days when users entered programs on punch
cards. They would give a batch of these programmed cards to the system
operator, who would feed them into the computer. Batch jobs can be stored up
during working hours and then executed during the evening or whenever the
computer is idle. Batch processing is particularly useful for operations that
require the computer or a peripheral device for an extended period of time. Once
a batch job begins, it continues until it is done or until an error occurs. Note
that batch processing implies that there is no interaction with the user while
the program is being executed.
For example: The
credit card companies process the billing system. The customer does not receive
a bill for each separate credit card purchase but one monthly bill for all of
that month’s purchases. The bill is created through batch processing, where all
of the data are collected and held until the bill is processed as a batch at
the end of the billing cycle.
Features
3) Information of master file is up to date only up to last
execution.
4) Magnetic tapes as well as magnetic disks are used, output
reports are printed in detail.
TIME SHARINGOPERATING
SYSTEM
Time-sharing is an approach to interactive computing in which a single
computer is used to provide simultaneous interactive general-purpose computing
to multiple users by sharing processor time. This is done by providing a
separate terminal to each user. Each terminal is connected to main computer
system. CPU time one by one. This short period of time is called time slice. The
user feels that he is having his own computer. In time sharing system hundreds
of users may be using the system simultaneously. It is not possible to keep the
programs of all the users in the memory at the same time. So operating system
keeps few programs in the main memory and the rest of the programs stored in
the disk.
Advantages
1) The response time is very less in case of time sharing
systems.
2) The CPU utilization is increased.
3) The memory management in time sharing system provides for
the protection and separation of user programs.
4) It is cost effective.
REAL TIME OPERATING
SYSTEM
When the time requirements on the operation of processor ot
the flow of data are very critical, then real time operating systems are used. Real
time means a quick response from the computer. In the real time system each
process is assigned a priority according to the importance of process. The processor
is normally allocated to the highest priority process among those which are
ready to execute.
For example:
1) Air traffic control system
2) Chemical process control system.
3) Scientific experiments
4) Real time simulations
5) Medical equipment
6) Automotive applications etc.
Types of real time systems:
1 Hard real time system
2 Soft real time system
ONLINE SYSTEMS
In online systems, there is direct interaction of the user
and the computer and the response time is very less. Each user is provided the
direct access to the CPU on time sharing basis. The transactions in the online
systems are processed as soon as the data is entered into the system.
For examples:
a)
Railway reservation system
b)
Banking system
c)
Stock prices in the stock market etc.
OFFLINE SYSTEMS
In
offline systems, the transactions are not processed immediately rather the data
is collected for some specific period of time and the processing is done after
the specific time. The batch processing is the best example of offline system
where the jobs are collected and processed after certain time interval.
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