What are the Types of Operating System

 
Types of Operating System
In this article, you will learn about the different types of operating system, advantages and disadvantages of different types of operating and their examples. To understand what the term operating system is, check my previous articled titled operating system and their functions



Batch Processing Operating System
This is a type of operating system that do not interact with the computer direct. In other words, any interaction that occurs between an end user and the computer does occur in the OS system. Rather, the user would have to prepare his job on punch in the batch form and then give to the computer operator. The rest now depends on the system operator whose duty is to arrange the tasks that are similar and have the same requirements in a group for execution or processing. The purpose of arranging or sorting the similar tasks in a group is to speed up the processing.

Examples of Batch Processing Operating System
The following are examples of batch processing operating system:
Transaction System
Bank Invoice System
Daily Report
Payroll System
Research Section

Characteristics of Batch Operating System
Batch operating system has various characteristics which are:
Jobs are executed in the order they are been programmed i.e first in first out.
An operator must be trained specially for this system
A user does not have direction interaction with the system but through the computer operator
Jobs that are similar and have the same requirements are grouped into batch for quick processing
Once the execution of a job is completed, the OS will free the memory of the CPU for other jobs

Advantages of Batch Processing Operating System
Though the batch processing operating system is somehow backward in functionalities, it also have some advantages which are:
The batch can be shared by multiple users
It makes the management of repeated tasks in the batch system easier
There is less idle time for the batch system
Its ability to know the next task to execute and how long it will take relieves the processor of stress
It is easy to schedule batch jobs for execution i.e jobs that the system can process when it's less busy

Disadvantages of Batch Processing Operating Systems
The following are some of the disadvantages of batch processing operating system:
Debugging of error in this system is difficult
Failure in any of the jobs in processing will cause the others to wait
Its operation is mainly depend on the computer operator
It is costly to acquire

Time Sharing Operating System
Time sharing operating system operates according to its name. In this system, multiple users can use the computer and share the CPU's time simultaneously. But, each user is allocated a time slice also known as quantum in a Round Robin form. During jobs' execution, the OS will monitored the current job to see if its allocated time is over or the job is been completed. If any of these conditions is found, the OS will move to the next job and execute it immediately.
Unlike the batch processing operating system, interaction between user and the computer is done in OS. Hence, the every user can execute its tasks without a trained computer operator.

Examples of Time Sharing Operating System
The following are some examples of time sharing operating system.
Linux
Unix
Multics
Windows 2000 server
Windows NT server
TOPS-10 (DEC)
TOPS-20 (DEC)

Advantages of Time Sharing Operating System
Some of the advantages of time sharing OS are:
Multiple users can use the computer simultaneously and smoothly
Each job is allocated the same amount of time otherwise known as time slice or quantum
It has the ability to run more than one programs simultaneously
It makes CPU become more productive as it reduces the CPU's idle time

Disadvantages of Time Sharing Operating System
Though time sharing OS has some advantages, it still has its own flaws which are:
Integrity and security of users data and programs are not guaranteed
There is less reliability in this OS
There is problem in data communication
It usually consumed a lot of resources therefore requires special operating system
Since it can executes multiple jobs and applications at the same time, there is chances of the system getting hang during switching between different jobs.

Distributed Operating System
This is a type of operating system were all computers are connected to a shared network as well as share files with each other. In this kind of system, a user of one system can access the files and applications in other systems in as much both are connected to the same network. However, each of the systems has their own memory and CPU therefore not depend on others for files storage and memory usage.
Furthermore, in this system the processors are connected through communication mediums such as telephone line and high speed buses in which every processor has its own resources and memory.

Characteristics of Distributed Operating System
Some of the features are:
Each of the systems connected has their own local storage and resources
All systems are connected via a shared network
These type of OS are expensive to acquire

Advantages of Distributed Operating System
Advantages of this system are:
The failure of one system does not stop the operation of others
The sharing of resources within the connected system makes its performance outstanding to single systems
Files in one system can be accessed via another system connected to the same network
Sharing of information is very fast due to the use of electronic mail
The speed of processing is improved while delay is reduce to some extent

Disadvantages of Distributed Operating System
It is an expensively OS to acquire
The sharing of files amongst systems connected to the network makes it vulnerable
Transmission of large data or files requires huge amount of bandwidth
Jobs execution may stop was the network is tempered with or went off
Overload issues may occur if proper care is not taken

Network Operating System
This type of operating system uses a local area network to establish connection between multiple computers and devices as well as managing the network resources effectively. It allows all users that are connected to the network to know about the underlying configuration of the other as well as connected users. It also gives the privilege to share files, printers, applications, security e.t.c.

Examples of Network Operating System
Ms Windows Server 2003 and 2008
Linux
UNIX
Novell NetWare
Mac OS X, etc.

Advantages of Network Operating System
The following are some of the advantages of network operating system:
There is a centralized server that other systems can remotely connect to.
Security monitory, prevention and control can be handled in server side.
Upgrade and integration of recent technologies and hardware in this system is easier.
The servers are highly scalable

Disadvantages of Network Operating System
The following are some disadvantages of this OS.
The whole connection will go offline once the server is down
There is need for regular update and maintenance
It is expensive to acquire

Real-Time Operating System
This operating system is named according to its core function. As the name suggested, it is an Operating System that is developed for real-time applications. In real-time applications, data are processed in a fixed small duration of time. RTOS allows multiple processes to be processed in a short interval of time. In other words, it can be referred to as an OS that is used in an environment where data to be process needs to be completed in a short period of time. RTOS is classified into types based on time constraint and these are;

a. Hard Real-Time Operating Systems
In this type of RTOS, time is one of the most critical factor that is put into consideration. The time required for a task to be achieved must be strictly adhere to else the end result might be disastrous and can lead to failure or damage of the proposed project. In simplified terms, Hard RTOS is a system that any result generated after the stipulated time might lead to fatal error. Examples of hard real-time operating system include: chemical and nuclear plant control, pacemakers, autopilot system in plane, diagnosis control system e.t.c.

b. Soft Real-Time Operating Systems
In Soft Real-Time Operating System, the schedule time can be a little bit exceeded yet the output will be useful but there will be a performance degradation. In a more simplified terms, the deadline for a specific task can only be delayed to an extent. In other words, it is recommended for tasks where timing is less critical. Examples of Soft RTOS are data management, weather station, smart phones, mobile communication, cameras, online transaction etc.

c. Soft Real-Time Operating Systems
In this type of RTOS, the output generated after the deadline is useless to the system but however does not caused any damage. Examples of this are multimedia products, online image processing e.t.c

Components of Real-Time Operating System/
Scheduler:  This specifies schedule for all execution of tasks of processes. Nevertheless, all tasks are performed by priority system.  This type of component of RTOS defines the schedule for all execution of entire tasks of process, but mostly all tasks are performed by priority system.

Synchronization Mechanism: This component help RTOS in handling different tasks in a parallel in order to improve or boost the system's performance. 
Memory Management: This is an important component of the RTOS as it helps to allocate memory space to each program in the system.
Interrupt Service Mechanism: It is used for handling interrupt when it occurs.
I/O Management: This component helps to provide good interface between input/output devices of the computer system
Fast Dispatch Latency: This helps the RTOS to maintain the gap between the intervals of completed tasks.

Advantages of Real-time Operating System
The following are some advantages of RTOS:
Allocation of memory is properly done
It makes jobs to be completed in a short period of time
It is an error free operating system
It is suitable for embedded systems due to its small size in nature
Every task in RTOS is performed in a predefined time frame
It has more speed up and CPU portability


Advantages of Real-time Operating System
Some disadvantages of Real-time Operating System are:
Only few number of tasks can run simultaneously to avoid errors
Failure to keep to stipulated time may render the output useless
It consume huge amount of the system resources therefore makes it to be very expensive to acquire
Its thread priority is very poor
It can't perform multi threading and multi tasking for a long time
It can only switch fewer tasks