Interview Question: What is Multithreading Multitasking Multiprocessing Multiprogramming
Interview Question: What is Multithreading Multitasking Multiprocessing Multiprogramming. Multitasking is the feature supported by the operating system to execute more than one task simultaneously. Multithreading is the system environment where the tasks are sharing the same programs load module under the multitasking environment. It is a subset of multitasking since it concerns task which use the same program.
Summary Definitions
- Multithreading: It is an extended form of multitasking.
- Multitasking: When a single resource is used to process multiple tasks then it is multitasking
- Multiprogramming: When multiple programs execute at a time on a single device, it is multiprogramming.
- Multiprocessing: When more than one processing unit is used by a single computer then it is called multiprocessing
What Is Multiprogramming Explain?
One of the most important aspects of an Operating System is to multi program. The main idea of multi programming is to maximize the CPU time. In a computer system, there are multiple processes waiting to be executed, i.e. they are waiting when the CPU will be allocated to them and they begin their execution. These processes are also known as jobs. Now the main memory is too small to accommodate all of these processes or jobs into it. Thus, these processes are initially kept in an area called job pool.
This job pool consists of all those processes awaiting allocation of main memory and CPU. CPU selects one job out of all these waiting jobs, brings it from the job pool to main memory and starts executing it. The processor executes one job until it is interrupted by some external factor or it goes for an I/O task.
What are the types of multiprogramming?
- Multitasking Operating System.
- Multiuser Operating System.
What Is Multitasking In Computing?
Multitasking refers to execution of multiple tasks, say processes, programs, threads etc. at a time. Multitasking also refers to having multiple programs, processes, tasks, threads running at the same time. This term is used in modern operating systems when multiple tasks share a common processing resource (e.g., CPU and Memory). Multitasking is a logical extension of multi programming. The major way in which multitasking differs from multi programming is that multi programming works solely on the concept of context switching whereas multitasking is based on time sharing alongside the concept of context switching.
What Is Multiprocessing In Computer And Example ?
Multiprocessing is the use of two or more CPUs (processors) within a single Computer system. The term also refers to the ability of a system to support more than one processor within a single computer system. The main advantage of multiprocessor system is to get more work done in a shorter period of time. These types of systems are used when very high speed is required to process a large volume of data. Multi processing systems can save money in comparison to single processor systems because the processors can share peripherals and power supplies.
Multiprocessing refers to the hardware (i.e., the CPU units) rather than the software (i.e., running processes). If the underlying hardware provides more than one processor then that is multiprocessing. It is the ability of the system to leverage multiple processors’ computing power.
What Is Multi threading?
Multi threading is the ability of a process to manage its use by more than one user at a time and to manage multiple requests by the same user without having to have multiple copies of the program. Benefits of Multi threading include increased responsiveness. Since there are multiple threads in a program, so if one thread is taking too long to execute or if it gets blocked, the rest of the threads keep executing without any problem. Thus the whole program remains responsive to the user by means of remaining threads.
An Example of Multi threading
We can think of threads as child processes that share the parent process resources but execute independently. Now take the case of a GUI. Say we are performing a calculation on the GUI (which is taking very long time to finish). Now we can not interact with the rest of the GUI until this command finishes its execution. To be able to interact with the rest of the GUI, this command of calculation should be assigned to a separate thread. So at this point of time, 2 threads will be executing i.e. one for calculation, and one for the rest of the GUI. Hence here in a single process, we used multiple threads for multiple functionality.
Difference Between Multithreading, Multitasking, Multiprocessing and Multiprogramming
| Multithreading | Multitasking | Multiprocessing | Multiprogramming |
| Multithreading is an extended form of multitasking. | In Multitasking, a single resource is used to process multiple tasks. | In multiprocessing, multiple processing units are used by a single device. | In multiprogramming, multiple programs execute at a same time on a single device. |
| More than one thread processed on a single CPU. | The process resides in the same CPU. | The process switches from one to another CPU as multiple processing units are used. | The process resides in the main memory. |
| The tasks are always further divided into sub tasks. | It is time sharing as the task assigned switches regularly. | It carries multiple processors to execute the task. | It uses batch OS. The CPU is utilized completely while execution. |
| It allows a single process to get multiple code segments. | Multitasking follows the concept of context switching. | A large amount of work can be done in a short period of time. | The processing is slower, as a single job resides in the main memory while execution. |
CPU is a super fast device and keeping it occupied for a single task is never a good idea. Considering the huge differences between CPU speed and IO speed, many concepts like multiprogramming, multitasking, multithreading, etc have been introduced to make better CPU utilisation.
Multitasking vs Multiprogramming | Difference Between Multiprogramming and Multi-tasking
| Multiprogramming | Multi-tasking |
|---|---|
| Multi-programming increases CPU utilization by organizing jobs. | In multi-tasking also increases CPU utilization, it also increases responsiveness. |
| Concept of Context Switching is used. | Concept of Context Switching and Time Sharing is used. |
| In multiprogrammed system, the operating system simply switches to, and executes, another job when current job needs to wait. | The processor is typically used in time sharing mode. Switching happens when either allowed time expires or where there other reason for current process needs to wait (example process needs to do IO). |
| It includes the single CPU to execute the program. | It uses multiple tasks for the task allocation. |
| The idea is to reduce the CPU idle time for as long as possible. | The idea is to further extend the CPU Utilization concept by increasing responsiveness Time Sharing. |
| Execution of process takes more time. | Execution of process takes less time. |
| In community edition, personalized shopping experiences is not created. | Promotions, personalized shopping experiences can be displayed in enterprise edition products. |
| It uses job scheduling algorithms so that more than one program can run at the same time. | Time sharing mechanism is used so that multiple tasks can run at the same time. |
Multiprogramming vs Multithreading
| Multiprogramming | Multithreading |
|---|---|
| The concurrent application of more than one program in the main memory is called as multiprogramming. | The process is divided into several different sub-processes called as threads, which has its own path of execution. This concept is called as multithreading. |
| It takes more time to process the jobs. | It takes moderate amount of time for job processing. |
| In this, one process is executed at a time. | In this, various components of the same process are being executed at a time. |
| The number of users is one at a time. | The number of users usually one. |
| The number of CPU is one. | The number of CPU can be one or more than one. |
| Its efficiency is Less. | Its efficiency is moderate. |
| It is economical. | It is economical. |
| Throughput is less. | Throughput is Moderate. |
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