What is a Multitasking Operating System?

It is an operating system that allows performing several tasks at the same time without any trouble. The system became more prominent after the introduction of personal computers.

A multitasking operating system is a type of system software that enables a computer to execute multiple tasks or processes simultaneously. This kind of operating system can manage and run several programs at the same time, allowing users to perform a variety of functions concurrently.

Table of Content

• What is a multitasking operating system?
• History
• How does a multitasking operating system work?
• Characteristics
• Types

What is a Multitasking Operating System?

A multitasking operating system is a logical extension of a multiprogramming operating system. Through this system, users can run multiple programs and tasks simultaneously. Without losing data, the operating system keeps track of each job and allows you to switch between jobs without allowing the data to be lost. All modern operating systems have complete multitasking capabilities, so multiple programs can run simultaneously without any interference.

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History of Multitasking Operating System

The history of multitasking operating systems goes back to the 1960s and 70s when the demand for computers has just started growing. The first multitasking operating system to be used, was the Compatible Time-Sharing System (CTSS). CTSS is a cooperative multitasking operating system that allows multiple users to simultaneously use a single system in a time-sharing environment.

By the 1970s, IBM introduced OS/360, its mainframe operating system that simultaneously handles multiple tasks. This system divided multiple tasks into small pieces and scheduled them to run on the CPU. 

In the 1980s, personal computers became more frequent in use, due to which multitasking operating systems were developed. AmigaOS was one of the first multitasking operating systems that allowed multiple programs to run simultaneously. In 1985, Microsoft released Microsoft Windows, which became immensely popular.

By the 1990s, true multitasking operating systems became more prevalent to support preemptive multitasking. This allowed operating systems to switch between tasks without requiring programs to cooperate.

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How do Multitasking Operating Systems work?

Such operating systems allow multiple programs and processes to run on a computer system simultaneously. Multitasking operating systems help manage allocating system resources such as CPU time, input/output devices, and computer memory among programs that are running. For this purpose, such operating systems use the following mechanisms: 

• CPU scheduling: Multi-task operating system manages CPU time allocation to each process. This ensures that every process has sufficient and equal CPU time. For this purpose, preemptive scheduling allows the operating system to interrupt any time-consuming process.
• Process management: The multitasking operating system manages those processes that are independent instances of programs that run concurrently. Here, the operating system allocates resources to every process and provides a mechanism for inter-process communication and synchronization.
• Memory management: The operating system manages both the allocation and deallocation of memory. This allows every process to access the memory it requires without interfering with other processes. 
• Input/output management: The operating system manages access to I/O devices and processes’ mechanisms. This allows the processes to request these devices and ensures that multiple processes can use the same device without interference. 

Characteristics of Multitasking Operating System

The following are the characteristics of a multitasking operating system:

• Hardware interruption: Such an operating system receives messages signifying that a peripheral in hardware needs attention. The system will then interrupt other tasks to focus on the peripheral.
• Time Sharing: This allows the operating system to simultaneously use a single computing resource by several users. The computer can switch swiftly between users and their requirements. 
• Context Switching: It is when the multitasking operating system executes a single job and performs another. 
• Memory Swapping: This is a technique that provides more memory than that available on the system. For this purpose, the portion of primary memory is kept in secondary storage. 
• Process allocation: Every process uses the space that is allocated to it. The process cannot change the data of another process in the main memory.
• Memory Protection: This allows safe and effective sharing of system resource access. Memory protection ensures the system with data integrity, general system stability, and data security.  
• Multithreading: An operating system can enable multiple users simultaneously without needing multiple copies of a program that runs on the computer. 

Types of Multitasking Operating Systems

The following are the types of multitasking operating systems:

1. Preemptive Multitasking Operating Systems

It is a technique that is based on the feature of time sharing. Each process in this multitasking computer system is allocated an equal share of computing resources. Additional time may be allocated depending on the task’s priority and criticality. To prevent a program from taking control of computing resources, this type of multitasking computer restricts the program to a limited number of time slices.

2. Non-preemptive Multitasking (Cooperative Multitasking)

This is a legacy multitasking technique that allocates an entire CPU to a single process till the time a process is completed. Here, CPU control remains largely with one program for a longer duration. This multitasking operating system works best with applications requiring intensive CPU resources for a continuous period. 

Whenever a program holds CPU for such long periods, it impacts other programs that must wait until the current program finishes. Some of the elements of cooperative multitasking are incorporated into this operating system. 

3. Hybrid Multitasking Operating Systems

It is an operating system that combines several types of multitasking. This type of system utilizes preemptive and cooperative multitasking techniques to optimize the system’s resources. Using this operating system ensures that multiple tasks can efficiently and smoothly run on the system. The preemptive multitasking part interrupts the running process to allow other processes to run, whereas cooperative multitasking allows the process to yield control voluntarily.

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