Introduction

People used stones, sticks, and bones as counting tools before the advent of computers. With the advancement of technology and the improvement of the human mind, more computing devices were developed with time like Abacus, Napier’s Bones, etc. These devices served as computers for performing mathematical computations but not very complex ones. In the early 19th century, with primitive designs the history of computers began and went on to change the world during the 20th century.

Today, we are so inextricably involved with computers that we can’t even imagine our world without them. As we are unable to work without computers, similarly computers can’t perform without an Operating System.

What is an Operating System (OS)?

An operating system (OS) is referred to as the most essential software that runs on a computer. It controls the memory and processes of a computer, besides all of its hardware and software. A computer is rendered useless without an operating system. One such OS is the Multi programming Operating System.

In this article, we will learn about what a multi programming operating system is, how it functions, their advantages and disadvantages, etc.

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What is the Multiprogramming Operating System?

A Multiprogramming operating system is defined as an operating system that assists the running of innumerable programs simultaneously on a single processor machine. If one program, in a multiprogramming operating system, has to wait for an input/output transfer, the other programs are in queue to use the CPU. This leads to various jobs sharing CPU time. The execution of their jobs, however, is not specified to be at the same time period.

When a program is being run, it is called a “Task”, “Process”, and “Job”. Simultaneous program executions help in improving system resource consumption and throughput in comparison to batch and serial processing systems.

The major objective of the multiprogramming operating system is to manage the resources of the entire system. The principle concept used by multiprogramming systems is Multiprogramming. The important components of a multiprogramming operating system are the command processor, file system, I/O control system, and transient area.

Subsequently, a multiprogramming operating system is designed in such a way so as to store different programs depending on sub-segmenting parts of the transient area. The resource management routines are linked with the core functions of the operating system.

Examples of Multiprogramming Operating System

There are various multiprogramming operating systems available.

Let us check out some examples of the multiprogramming operating system.

• Desktop operating systems, namely Windows, Linux distributions, macOS, etc. These are referred to as modern operating systems and in their functioning include various multiprogramming concepts. A user is capable of running multiple jobs on a system utilizing one of these (or more) operating systems at the same time. For instance, many games have been designed for using a single processor core.
• On iOS, Android, and other mobile operating systems on the phone, one can watch videos while also sending and receiving whatsapp messages.
• Application software, such as media players, popular web browsers, Microsoft Office, etc. Any latest web browser would allow a user to visit multiple websites simultaneously by launching as many windows/tabs as needed.
• Other examples are Windows OS, Microcomputers such as XENIX, DESQview, and MP/M.

Types of the Multiprogramming Operating System

A Multiprogramming operating system can be categorized into two types, and they are:

• Multitasking Operating System
• Multiuser Operating System

Multitasking Operating System

“Multitasking” – this is the word that today’s modern computers use. A multiprogramming operating system that authorizes innumerable applications to carry out simultaneously supports multitasking as a rational extension. In this method, a CPU and other shared processing resources are distributed among several tasks, also called processes.

Operating systems, especially those that support multitasking, are better at managing virtual memory and hard disks. Due to the shorter wait times, the processing time is also effectively utilized.

Suppose for instance, you wish to download a file using the internet. Now, without waiting for the file to download fully, you may put the computer into use for other things. In the primary memory, one process is not capable of modifying the data of another process. The assigned space for utilization of each process may only be used. Other programs employing the computer that may create mistakes are unaffected by them. For example, your data in Microsoft Excel will not get impacted if Google Chrome crashes.

Each user is at liberty to independently run their own programs. Smartphone apps promote multitasking and can open many programs at once.

Multiuser Operating System

The multiuser operating system is referred to as a computer operating system that allows multiple users to connect to a sole system running the same operating system. Some examples of this type of operating system are Unix, Linux, Ubuntu, Windows 2000, Mac OS, etc.

We can run many programs simultaneously, using a multi-user operating system, and execute multiple tasks at once. The major reason for designing a multi-user operating system is to be employed for time-sharing and batch processing on mainframe systems. Nowadays, the public sector, colleges and universities, large corporations, and servers running Ubuntu Server or Windows Server often employ this multi-user operating system. These servers grant access to hardware, operating system, and kernel simultaneously for several users.

Also, files or data, as well as different peripherals like printers and hard drives can be exchanged. Each user is allowed a brief period of CPU time for this.

How does a Multiprogramming Operating System work?

Multiprogramming is referred to as interwoven execution of many tasks on one computer system. Multiple users, in a multiprogramming operating system, can accomplish their tasks concurrently and save some primary memory. While a program carries out I/O operations, the CPU may allocate time to other idle mode applications. Therefore, it is possible to share the CPU time for many tasks.

Multiple programs may be allowed to share CPU time while a particular program is on stand-by for an I/O transfer and another is constantly getting ready to use the pr
ocessor. Although not all tasks are carried out at the same time, more than one job may operate on the processor concurrently, with portions of other processes being finished first, accompanied by another segment, and so on. To execute all the programs, the operating system must make sure CPU resources are allocated sufficiently to each program and reallocated as resources become accessible.

Two processes will never be actually permitted to use a common resource such as the processor simultaneously. Yet, the mechanism of utilizing these resources is not even similar to serial/sequential. In the sequential process, one program would be assigned to the CPU. Once this job is completely executed, another job will be assigned to the CPU, and so on, that is serially. A method called context switching that the OS uses to attain this, makes certain that a program’s state is preserved in memory and easily available as the OS shifts between CPU assignments and applications.

The overall purpose of a multiprogramming operating system is keeping the CPU busy until all the tasks get entirely executed. Thus, a single processor computer may run several programs at the same time having the CPU never being idle. Multiprogramming permits a more effective utilization of resources by establishing a number of concepts such as prioritizing, preempting, scheduling, etc.

Features of Multiprogramming Operating System

The multiprogramming operating system comes with many features. Below mentioned are few of the primary features of a multiprogramming operating system:

• A slower response time is required
• It might be helpful in running multiple tasks simultaneously in one application
• It assists in enhancing the entire job throughput of a computer
• Multiple users can use the multiprogramming system at once
• For urgent tasks, it might assist in reducing turnaround time
• It is constantly active and enhances efficiency of the CPU
• The resources, part of the multiprogramming operating system, are widely used

Difference between Multiprogramming and Multitasking

Before learning about the differences, first let us understand what Multitasking is.

Multitasking can be referred to as a logical extension of multiprogramming. Multitasking is defined as the ability of an OS to run more than one task at the same time on a CPU machine. These multiple tasks share common resources (like memory and CPU). In multitasking systems, the CPU runs multiple jobs by typically shifting among them using a small time quantum, and the shifting occurs so fast that the users feel like interacting with each running task simultaneously.

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Both Multiprogramming and Multitasking are connected to Operating Systems Concepts. CPU is considered to be a super fast device and it is never a good idea for a single task to occupy it. Taking into account the huge differences between IO speed and CPU speed, many concepts like multitasking, multiprogramming, multithreading, etc have been created to make better utilization of CPU. The difference between multiprogramming and multitasking is discussed below.

Both the concepts of Multiprogramming and Multitasking are introduced for a single CPU. However, multitasking is a logical extension of multiprogramming. In both systems, the concept of Context Switching is used but in addition to this Time Sharing concept is also used in multitasking. Multiprogramming enhances CPU utilization by organizing jobs. The multitasking system also enhances responsiveness besides increasing CPU utilization.

In a multiprogrammed system, the operating system simply shifts to, and runs, another job when the current job is awaiting. In a multitasked system, the processor is used typically in time sharing mode. Shifting occurs when either time permitted expires or where there are other reasons for which the current  job needs waiting. The idea of a multiprogramming system is to reduce the idle time of the CPU to a great extent, while the idea of a multitasked system is to further extend the concept of CPU utilization by enhancing the responsiveness time sharing.

Multitasking is used by most of the modern operating systems.

Difference between Multiprogramming and Multiprocessing

Before learning about the differences, first let us understand what Multiprocessing is.

Multiprocessing is considered to be a system that possesses two or more than one processor. The CPUs are added in this for increasing the computing speed of the system. There are multiple processes, because of Multiprocessing, that are executed at the same time. Multiprocessing can be further classified into two categories: Symmetric & Asymmetric Multiprocessing.

By now, we are aware of what a multiprogramming operating system is, so now let’s move on to the difference between multiprogramming and multiprocessing.

Multiprogramming is referred to as the simultaneous application of multiple programs in the main memory whereas multiprocessing is the availability of multiple processors per system that can run numerous sets of instructions. For multiprogramming, the number of CPU required is one but can be more than one in case of multiprocessing. The job processing is faster in case of multiprocessing compared to that of multiprogramming.

Only one process can be executed at a time in multiprogramming while in multiprocessing, multiple processes can be executed simultaneously. In multiprogramming, user count is one at a time but user count can be multiple in case of multiprocessing. Though both the systems are economical but throughput and efficiency both are less in multiprogramming whereas both are maximum in a multiprocessing system.

Difference between Multiprogramming and Multithreading

Before learning about the differences, first let us understand what Multithreading is.

Multithreading is defined as a technique in which multiple threads are produced of a process for enhancing the system’s computing speed. In multithreading, numerous threads of a process are executed at the same time.

As we already know, multiprogramming may be defined as the simultaneous application of multiple programs in the main memory. Whereas, multithreading is a process which is divided into innumerable sub-processes known as threads each having their own path of execution. Multithreading takes moderate time to process a job compared to multiprogramming which takes more time.

In multiprogramming, one process is executed at a time while in multithreading, different components of the same process are executed simultaneously. User count for both the systems are one user at a time but CPU required may be more than one in case of multithreading. Though both multiprogramming and multithreading systems are economical, the throughput and efficiency is less for multiprogramming than multithreading which is moderate.

Advantages of Multiprogra
mming Operating System

There are several advantages of a multiprogramming operating system which are mentioned below:

1. Unless there are no jobs to run, the processor rarely becomes idle and is utilized most of the time.
2. Since all the jobs are executed parallelly amongst themselves, the system becomes fast.
3. Jobs that necessitates the need for a CPU for a short duration are completed earlier when compared to those with long requirement time for CPU.
4. A Multiprogramming operating system supports multiple users on the computer system.
5. Efficient and even resource utilization.
6. Total time necessary to execute a job is reduced.
7. A multiprogramming operating system is well equipped to deal with applications in which more than one job is to be executed.

Disadvantages of Multiprogramming Operating System

There are also certain disadvantages of the multiprogramming operating system. They are as follows:

1. Processes necessitating long CPU times, sometimes, have to be on standby for other usually shorter jobs to finish.
2. In multiprogramming, it is not simple to keep track of a large number of processes.
3. Owing to the complicated nature of handling schedules, a multiprogramming operating system is not a simple job.
4. A multiprogramming operating system has to employ CPU scheduling.
5. Memory management should be very effective.
6. While a program runs, there cannot be any interaction between the user and the program.

Conclusion

Let us summarize the details of a multiprogramming operating system that we learnt so far in the article.

A multiprogramming operating system is referred to as a system that can run innumerable programmes on a single processor concurrently. In an operating system with more than one programme, other programmes utilize the CPU and other resources when one programme is on standby for an I/O transfer.

Multiprogramming is defined as the process of running innumerable tasks at the same time on the same computer system. One of the major goals of multiprogramming is to manage the different resources of the entire system. iOS, Windows, Firefox, Excel, and other such systems are examples of the multiprogramming operating system.

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