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Operating System
In this post, we will discuss general properties, types of application advantages, disadvantages and basic requirements of different types of operating systems.
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Batch Operating System
Batch processing requires the grouping of similar jobs, which consist of programs, data, and system commands.
The advantage of this type of programming is in programs with large computation time, where need of interaction or involvement of programmer with system almost not required. For example, programs like payroll, statistical analysis of data, and calculation of large scientific numbers. They can submit their programs to the operators and return later after some time to collect the output.
Major Disadvantage Of This Operating System
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- Non-interactive environment.
- Off-line debugging of the program by the operator.
- No control over intermediate results of a program.
- No flexibility in developing software.
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Real-Time Operating System
A real-time operating system [RTOS] is an operating system that guarantees a certain capability within a specified time constraint. Primary role of real-time operating system is to process data in quick time.
In other words, a real-time system is a system that reacts to events in the environment by performing predefined functions within specified given time period.
A real-time system is a system that ensures the exact time requirements for a job. If a real-time system does not complete task in a certain time, it may cause a breakdown of the entire system it is running.
Some Applications Require To Be Serviced Within A Time Period
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- Industrial Control Systems.
- Automobiles [Brake Control].
- Airplane Guidance.
- Medical Devices.
There Are Two Types Of Real-Time Systems
Hard Real-Time Systems
A hard real-time system guarantees that a job will complete within a specified time period. This system must ensure that all delays on processing, input, and output are bounded. The system cannot wait indefinitely so the hard time systems are usually very limited. There is generally no secondary storage such as disk drives as a disk request can take a variable time low process.
Some examples of a hard real-time system are the software that runs the autopilot in a jumbo jet or the imaging software on a missile.
Soft Real-Time Systems
A soft real time system is a much less restrictive version of a hard real-time system. A soft real-time system does not guarantee that a job will complete within a specified time period, however, it tries its best to finish the job as soon as possible. If a critical real-time job enters the system, the operating system may assign the highest priority to that task and execute it continuously until it completes.
The lack of a guarantee makes a soft real-time system more limited in its application for industrial activities. Soft real time systems are used in the area of multimedia, virtual reality, etc. Some of the operating systems that provide soft real time support are Windows NT/2000, Linux, Solaris.
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Time-Sharing Operating System
With batch processing systems, there was no interaction between the user and his/her program in execution [process] while the program was being executed. The time sharing system allows multiple programs to simultaneously share computer resources. In this everything is done under operator control. The job is submitted by the user and it is executed at some other time and the output is prepared. The delay between job submission and job completion is called the turnaround time.
Modern computer systems are interactive. The user asks for OS services directly and receives an immediate response. The user can easily experiment and do fast debugging.
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Personal Computer Operating System
The more popular way that programmers and users got back at the machine was the advent of personal computers around 1980. Finally, computers became small enough, inexpensive and even an individual could own them now a days. Modern era personal computers [PC] possess all basic features of computers and are very powerful in terms of CPU processing.
The Operating System Of PCs Consists Of Two Parts
Basic Input Output System [BIOS]
Basic Input Output Systems [BIOS] in PCs are stored in a non-erasable memory called Read-Only Memory [ROM]. When power is turned on BIOS takes control of the system in the beginning of booting.
Disk Operating System [DOS]
Disk Operating System [DOS] is stored in a hard disk of the personal computer system. Features of DOS are:
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- File Management
- Directory Management
- Memory Management
- Utility Program Management
- Executive Program management
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Network Operating System
The network operating system is the collection of software and protocols [set of rules]. This collection allows the intercommunication of many computers over a computer network. Each computer on the network has its own operating system.
Features Of Network Operating System
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- Each computer has its own operating system instead of running part of global system wide operating system.
- Login mechanism is used to connect computer with remote server or system.
- Allows users to access the various resources of the network system.
- Users of the network systems are aware of where their files are kept and can move their files from one system to another.
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Parallel Operating System
It is a multiprocessor operating system which works with more than one CPU in close communication. It is also called tightly coupled system because in this system processors share a common memory and clock; communication usually takes place through the shared memory. Processors in the system are divided into two categories master and slave. Master processors control the slave processors.
Advantages Of Parallel System
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- Increased throughput.
- Economical.
- Increased reliability.
- Graceful degradation.
- Fail-Soft systems.
- Symmetric multiprocessing [SMP].
- Each processor runs an identical copy of the operating system.
- Many processes can run at a time without performance deterioration.
- Most modern operating systems support SMP.
- Each processor is assigned a specific task; master processor schedules and allocates work to slave processors.
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Distributed Operating System
A distributed operating system is one that looks to its users like an ordinary centralized operating system but runs on multiple independent CPUs. These systems are considered to be more reliable than uniprocessor based systems. They are functional even if some of their hardware is not functioning or is out of order.
Distributed operating systems are considered to be more reliable than single processor based systems. They perform even if some part of the hardware is malfunctioning.
Advantages Of Distributed Operating System
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- Distributed operating system offers better price performance than centralized operating system.
- Total computing power of distributed operating system is better than the centralized operating system.
- If one machine crashes the system as a whole survives and keeps on working.
- Computing power can be added in small increments.
- Allows many users to access a common database.
- Allows many users to share expensive peripheral devices.
- Human-to-human communication makes easier through a wide network.
Related Posts
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Input And Output Devices
Classification Of Software
Evolution Of Operating System
