What is the difference between multitasking multiprogramming and multiprocessingΣυμβουλή Όταν?

Answer 1

I have both BSCS and MSCS, with 24 years in industry, and I have heard the use of these terms vary depending upon who is using them, but this is my view based on my experience.

Multiprogramming is an old and arcane term, that was originally used to describe the earlier timesharing type of system where multiple jobs/Programs could be submitted to a computer system, and it should share its various resources between all of the jobs that were running. The jobs/programs were not decomposed beyond the job level, and this was the granularity of the CPU and resource sharing that occurred. It is true to say that multiprogramming is still supported today on modern computers because it is true that multiple jobs/programs are running at once. However, this is true of all computers now, and is not even a relevant consideration. What is relevant though is the level of sharing that has changed dramatically over the years.

Now, the terms multitasking, multiprocessing and multithreading, mean the exact same thing in the general sense, and none has any dependency on the number of CPUs in a system. The first thing to understand here is that the words are basically synonymous in the general sense in that, a task is a process is a job is a thread is a program. Its all based on your POV. Where these terms start to take on specific meaning is when viewed in the context of a specific execution environment where a program is designed, compiled, loaded and executed on a specific piece of computer hardware. This context might assign a hierarchical meaning such as a program is the highest level of organization that decomposes into multiple tasks that run separately, that each can be decomposed into one or more processes, that can be further decomposed into some number of threads. Just an example.

You can take that same decomposition and apply it in the compiler used to build software for a true multiprocessor system, and it will look for these, and also other patterns of execution that allow load balancing between the processors. Such tools will also usually allow for high level partitioning, but will also usually have automatic load balancing mechanisms in place that try to maximize CPU utilization. In the end, the multiprocessor system is executing the software in the same way on each processor, but can get real parallelism not found in a single processor system.

The use of such terms is also influenced by how a program is designed because it can be designed to execute as single monolithic beast with a single execution path through it, or it can be specifically designed as a set of independent units that all get started by the program, and do all the work. Such units are called tasks, processes, functions, and even threads. One can enter into debates that a thread is really a light weight process, as opposed to a heavy weight process, but then one starts to get into the boring minutia of how processes are represented by the OS,etc, and this is always context specific, and not worth the time.

All computers and operating systems in use today support very fine grained sharing of the CPU between multiple jobs, tasks, threads, processes, and some even analyze the code instructions at runtime to determine which blocks of instructions can be run out of order.

in simple words multitasking/ multiprogramming conveys single processor and multiprocessing connotes to 2 processors being used to accomplish a task/job.

A minor difference between multitasking and multiprogramming can be understood by help of threads in JAVA where each (more than 1 program) program being run attributes to multiprogramming and each thread within a program connotes to multitasking as they share time with and r run concurrently......

For all the terminologies Multiprogramming is the core. Multiprogramming is the process of loading more than one program into the memory so that processor can be kept busy by switching between any of the loaded programs. Multitasking is derivation of multiprogramming where the operating system treats the programs loaded in the memory as task. But multiprocessing mainly deals with the hardware. Here more than one processing unit (CPU) comes into the picture. Multiprocessing leads to parallel computing.

The difference of these three words/computer jargon is that: 1. Multitasking is the ability of a computer to handle a number of tasks or jobs simultaniously, while multiprogramming is the capacity to run or handle several programs at the same time. Lastly but not the least, multiprocessing is the ability or capacity of a computer to handle or rather solve a particular task in various ways. Hope you will make some sense out of this.

Mutitasking and mutiprogramming are basically one and the same thing, in which the computer handles many tasks or programs simultniously. but multiprocessing is the techniuqe of handling one or more jobs in different ways, like in mutiprocessor architecture.

Multi programing means executing more than one program ,but here when ever the processor is idle during execution of one process it go for execution of another program.Where as in Multitasking,this is a combination of both multi programing and time sharing.means in this it will execute more than one process simultaneously.

The term Multitasking is used when more than one applications/programs/tasks are being run on a single processor. On the other hand, Multi-Processing is the ability to use more than one processor (CPU), on a single machine.