[multithreading] Difference between multitasking, multithreading and multiprocessing?

Whats the difference between multitasking, multiprogramming & multiprocessing

This comes regularly for my university OS exams and I can't find a good answer. I know quite a bit about multitasking and multiprogramming, but need to confirm it.

A multiprogramming is the process when a computer system is performing different tasks all at once in a single computer system.

MULTIPROCESSING is like the OS handling the different jobs in main memory in such a way that it gives its time to each and every job when other is busy for some task such as I/O operation. So as long as at least one job needs to execute, the cpu never sit idle. and here it is automatically handled by the OS, without user interaction with computer.

But when we say about MULTITASKING, the user is actually involved with different jobs as at one time - minesweeper or checking mail or anything. The cpu executes multiple jobs by switching among them, but the switching is so fast that user has the illusion that both the applications are running simultaneously.

So the main difference between mp and mt is that in mp the OS is handling different jobs in main memory in such a way that if some job is waiting for something then it will jump for the next job to execute. And in mt the user is in interaction with the system and getting the illusion as both or any of the applications are running simultaneously.

Multiprogramming - This term is used in the context of batch systems. You've got several programs in main memory concurrently. The CPU schedules a time for each one.

I.e. submitting multiple jobs and all of them are loaded into memory and executed according to a scheduling algorithm. Common batch system scheduling algorithms include: First-Come-First-Served, Shortest-Job-First, Shortest-Remaining-Time-Next.

Multitasking - This is basically multiprogramming in the context of a single-user interactive environment, in which the OS switches between several programs in main memory so as to give the illusion that several are running at once. Common scheduling algorithms used for multitasking are: Round-Robin, Priority Scheduling (multiple queues), Shortest-Process-Next.

Multi-programming :-

More than one task(job) process can reside into main memory at a time. It is basically design to reduce CPU wastage during I/O operation , example : if a job is executing currently and need I/O operation . I/O operation is done using DMA and processor assign to some Other job from the job queue till I/O operation of job1 completed . then job1 continue again . In this way it reduce CPU wastage .

Multitasking:- It handling a number of tasks or jobs simultaneously. In that case user can interact with the system.

Multiprogramming:- It handling a several programs at the same time & it cannot interact with the system, every thing is decided by the OS(Operating System).

Multiple threads can exist in a single process. The threads that belong to the same process share the same memory area (can read from and write to the very same variables, and can interfere with one another). On the contrary, different processes live in different memory areas, and each of them has its own variables. In order to communicate, processes have to use other channels (files, pipes or sockets).

If you want to parallelize a computation, you're probably going to need multithreading, because you probably want the threads to cooperate on the same memory.

Speaking about performance, threads are faster to create and manage than processes (because the OS doesn't need to allocate a whole new virtual memory area), and inter-thread communication is usually faster than inter-process communication. But threads are harder to program. Threads can interfere with one another, and can write to each other's memory, but the way this happens is not always obvious (due to several factors, mainly instruction reordering and memory caching), and so you are going to need synchronization primitives to control access to your variables.

Source

Multiprogramming: More than one task/program/job/process can reside into the main memory at one point of time. This ability of the OS is called multiprogramming.

Multitasking: More than one task/program/job/process can reside into the same CPU at one point of time. This ability of the OS is called multitasking.

Multiprogramming:- in which execution of multiple jobs by the same computer not at the same time.

Multitasking :- o/s in which more than one task are executed at the same time.

In a multiprogramming system, there are more than one programs loaded in main memory which are ready to execute. Only one program at a time is able to get the CPU for executing its instructions while all others are waiting their turn. The main idea of multiprogramming is to maximize the use of CPU time. Suppose currently running process is performing an I/O task, then OS may interrupt that process and give the control to one of the other in - main memory programs that are ready to execute (i.e. process context switching). In this way, no CPU time is wasted by system waiting for the I/O task to be completed.

MultiProcessing - Multiprocessing is the ability of an operating system to execute more than one process simultaneously on a multi processor machine. In multiprocessing system, a computer uses more than one CPU at a tme.

Multitasking - Multitasking is the ability of an operating system to execute more than one task simultaneously on single processor machine, these multiple tasks share common resources such as CPU and memory. In multitasking system, CPU switches from one task to next task so quickly that appears as all tasks are executing at the same time.

There are differences between multitasking and multi programming. A task in a multitasking system is not whole application program but it can refers to a "thread of execution" when one process is divided into sub-tasks. Each smaller task does not hijack the CPU until it finishes, they share a small amount of the CPU time called Quantum. Multi programming and multitasking operating systems are time sharing systems.

Multi threading - Multi threading is the extension of multitasking. Multi threading is the ability of an operating system to subdivide the specific operation within a single application into individual threads. Each of these threads can run in parallel. The OS divides processing time not only among different applications but also among each thread within an application.

Multiprogramming: It means running several programs on computer.Here user cannot interact with the system,everything is decided by the OS.

Multitasking: It is a logical extension of multiprogramming.It means running several tasks on computer.Switching between the jobs is so fast that the user can interact with the system.

Multithreading: Basically seen when more number of clients access the server.

MultiProgramming - In a multiprogramming system, there are more than one programs loaded in main memory which are ready to execute. Only one program at a time is able to get the CPU for executing its instructions while all others are waiting their turn. The main idea of multiprogramming is to maximize the use of CPU time. Suppose currently running process is performing an I/O task, then OS may interrupt that process and give the control to one of the other in - main memory programs that are ready to execute (i.e. process context switching). In this way, no CPU time is wasted by system waiting for the I/O task to be completed.

MultiProcessing - Multiprocessing is the ability of an operating system to execute more than one process simultaneously on a multi processor machine. In multiprocessing system, a computer uses more than one CPU at a tme.

Multitasking - Multitasking is the ability of an operating system to execute more than one task simultaneously on single processor machine, these multiple tasks share common resources such as CPU and memory. In multitasking system, CPU switches from one task to next task so quickly that appears as all tasks are executing at the same time.

There are differences between multitasking and multiprogramming. A task in a multitasking system is not whole application program but it can refres to a "thread of execution" when one process is divided into sub-tasks. Each smaller task does not hijack the CPU until it finishes, they share a small amount of the CPU time called Quantum. Multiprogramming and multitasking operating systems are time sharing systems.

Multithreading - Multithreading is the extension of multitasking. Multithreading is the ability of an operating system to subdivide the specific operation within a single application into individual threads. Each of these threads can run in parallel. The OS divides processing time not only among different applications but also among each thread within an application.

Multithreading Multithreading extends the idea of multitasking into applications, so you can subdivide specific operations within a single application into individual threads.

Multiprogramming - A computer running more than one program at a time (like running Excel and Firefox simultaneously)

Multiprocessing - A computer using more than one CPU at a time

Multiprogramming - More than one task/program/job/process can reside into the main memory at one point of time. This ability of the OS is called multiprogramming.

Multitasking: More than one task/program/job/process can reside into the same CPU at one point of time. This ability of the OS is called multitasking.

Multiusers System - a computer system in which multiple terminals connect to a host computer that handles processing tasks.

Both multiprogramming and multitasking solve different problems, though they use similar method of switching between the processes.

Multiprogramming : In the early days, it was seen that at times certain processes where using peripherals (e.g.: I/O). In such cases, the CPU remained idle. To use the CPU more efficiently, it was prudent to load multiple processes in the memory. This way, if a certain process were to use the peripheral, certain other process would use the CPU. This was multiprogramming in action.

Multitasking : To the end user, multiple processes had to appear running at the same time. This was mocked by switching between different processes and by making them run on the CPU simultaneously. This was the idea behind multitasking.

Multitasking - It is also called time sharing because multiple tasks(or processes) can be switched regularly, in a particular time, so that the user can get a view that they are operating concurrently.

Multi-threading - To make the user experience richer, the tasks(in a single process) are further divided into sub-tasks. These sub-tasks then can operate in a multi-tasking environment.

Multiprocessing - It is the process of having multiple processors to run a process(or program), in a given time. It decreases the computation time.

Multi programming - It is used in batch operating systems, generally. Here, the job(or process) gets the full CPU and memory while execution. Multi programming is the system in which many different programs are loaded in computer's main memory, and the first one begins to run. When it finishes its execution(i.e., in running state) and waits for peripheral(i.e., waiting state), the next process begins to run. This is in contrast to multi-tasking, in which case each task is allotted a time slot(also called quantum) for its execution.

Multi-programming :-

More than one task(job) process can reside into main memory at a time. It is basically design to reduce CPU wastage during I/O operation , example : if a job is executing currently and need I/O operation . I/O operation is done using DMA and processor assign to some Other job from the job queue till I/O operation of job1 completed . then job1 continue again . In this way it reduce CPU wastage .

Multi -Tasking :-

In this type of OS multiple task(process) are performed concurrently (Concurrently does't mean that task executing exactly at same time instant ..as multitasking does't imply parallelism ) . In this system a new task start before other task ended depend on CPU scheduling technique it uses && all processes share common resources .

Multi -Processing :-

Use 2 or more processor within single CPU . So task can execute in parallel .But some synchronization b/w them is needed .

Basically Multi-programming is a concept where you run more than one program simultaneously, suppose you run two programs like chrome(browser) and calculator(system application).

Multi processing is where a user uses more than one processor to accomplish a task.

To know Multi threading we need to know what is a thread. A thread is basically a part of a program running within the program. Best example of thread is the tabs of a browser. If you have 5 tabs which are being opened and used then the program actually creates 5 threads of the program, this concept is called multi-threading.

Multitasking - This is basically multiprogramming in the context of a single-user interactive environment, in which the OS switches between several programs in main memory so as to give the illusion that several are running at once. Common scheduling algorithms used for multitasking are: Round-Robin, Priority Scheduling (multiple queues), Shortest-Process-Next.

MULTIPROCESSING is like the OS handling the different jobs in main memory in such a way that it gives its time to each and every job when other is busy for some task such as I/O operation. So as long as at least one job needs to execute, the cpu never sit idle. and here it is automatically handled by the OS,

Multiprogramming- Jobs to be executed are loaded into a pool. Some number of those jobs are loaded into main memory, and one is selected from the pool for execution by the CPU. If at some point the program in progress terminates or requires the services of a peripheral device, the control of the CPU is given to the next job in the pool. As programs terminate, more jobs are loaded into memory for execution, and CPU control is switched to another job in memory. In this way the CPU is always executing some program or some portion thereof, instead of waiting for a printer, tape drive, or console input

Multiprocessing - the simultaneous execution of two or more programs or instruction sequences by separate CPUs under integrated control

multitasking System - the concurrent or interleaved execution of two or more jobs by a single CPU.

Multiusers System - a computer system in which multiple terminals connect to a host computer that handles processing tasks.

None of the above answers except Mr Vaibhav Kumar's are clear or not ambiguous. [sorry, no offense]

Both multi programming and tasking are same concept of switching task in processor, difference is in the concept and reason of the switching.

MProgramming: to not keep processor idle when active task needs longer IO or other non CPU response then, processor loads and works on another task that is not waiting for IO and ready for process.

MTasking: even after MPrograming, to user it may feel like only one task is executing and another is simply waiting to come to cpu. So the active task is also swapped from active CPU and kept aside and another task is brought in CPU for a very small fraction of human time[second], and swapped back to the earlier task again. In this way user will feel both task are alive in CPU at same time. But actually each task is active only once at a given CPU time[in micro or nano second]

And MProcessing is, like my computer have quad core, so I use 4 processor at a time, means 4 different multiprogramming instances happen in my machine. And these 4 processors does another numerous no of MTasking.

So MProcessing>MProgramming>Mtasking

And MThreading n another breakup of each task. that also to give user a happy life. Here multiple tasks[like word doc and media player] are not coming in picture, rather small subtasks like coloring of text on word and automatic spell check in word are part of same word executable.

not sure if I was able to make clear all confusions...

Multiprogramming-More than on job in main memory.

Muntitasking - More than one program run simultaneously. that is more than one program in CPU.

Multitasking (Time sharing):

Time shared systems allows many users to share the computer simultaneously.

Multiprograming

Running more then one program with in an application to perform a certain task.

Example : In MS WORD, Writing in document and sending Email

Multitasking

Running more then one application to perform a certain task.

Example: listening Song, playing game, work in ms word, excel and other applications simultaneously

Multiprocessing

Running more then one instruction through a processor.

Example When create a file then computer takes Time and date default.