In this article, we will discuss the differences between Multitasking and Multithreading. People generally get confused between these terms. On one hand, Multitasking is a logical extension to multiprogramming, and on the other hand, Multithreading is thread-based multitasking.
The basic difference between Multitasking and multithreading is that Multitasking allows CPU to perform multiple tasks (program, process, task, threads) simultaneously whereas, Multithreading allows multiple threads of the same process to execute simultaneously. Let us discuss the differences between Multitasking and Multithreading with the help of comparison chart shown below.
Content: Multitasking Vs Multithreading
Comparison Chart
| Basis for Comparison | Multitasking | Multithreading |
|---|---|---|
| Basic | Multitasking let CPU to execute multiple tasks at the same time. | Multithreading let CPU to execute multiple threads of a process simultaneously. |
| Switching | In multitasking CPU switches between programs frequently. | In multithreading CPU switches between the threads frequently. |
| Memory and Resource | In multitasking system has to allocate separate memory and resources to each program that CPU is executing. | In multithreading system has to allocate memory to a process, multiple threads of that process shares the same memory and resources allocated to the process. |
Definition of Multitasking
Multitasking is when a single CPU performs several tasks (program, process, task, threads) at the same time. To perform multitasking, the CPU switches among theses tasks very frequently so that user can interact with each program simultaneously.
In a multitasking operating system, several users can share the system simultaneously. As we saw the CPU rapidly switches among the tasks, so a little time is needed to switch from one user to the next user. This puts an impression on a user that entire computer system is dedicated to him.
When several users are sharing a multitasking operating system, CPU scheduling and multiprogramming makes it possible for each user to have at least a small portion of Multitasking OS and let each user have at least one program in the memory for execution.
Definition of Multithreading
Multithreading is different from multitasking in a sense that multitasking allows multiple tasks at the same time, whereas, the Multithreading allows multiple threads of a single task (program, process) to be processed by CPU at the same time.
Before studying multithreading let us talk about what is a thread? A thread is a basic execution unit which has its own program counter, set of the register, stack but it shares the code, data, and file of the process to which it belongs. A process can have multiple threads simultaneously, and the CPU switches among these threads so frequently making an impression on the user that all threads are running simultaneously and this is called multithreading.
Multithreading increases the responsiveness of system as, if one thread of the application is not responding, the other would respond in that sense the user would not have to sit idle. Multithreading allows resource sharing as threads belonging to the same process can share code and data of the process, and it allows a process to have multiple threads at the same time active in same address space.
Creating a different process is costlier as the system has to allocate different memory and resources to each process, but creating threads is easy as it does not require allocating separate memory and resources for threads of the same process.
Key Differences Between Multitasking and Multithreading in OS
- The basic difference between multitasking and multithreading is that in multitasking, the system allows executing multiple programs and tasks at the same time, whereas, in multithreading, the system executes multiple threads of the same or different processes at the same time.
- In multitasking, CPU has to switch between multiple programs so that it appears that multiple programs are running simultaneously. On other hands, in multithreading CPU has to switch between multiple threads to make it appear that all threads are running simultaneously.
- Multitasking allocates separate memory and resources for each process/program whereas, in multithreading threads belonging to the same process shares the same memory and resources as that of the process.
Conclusion
Multitasking is similar to multiprogramming whereas, Multithreading is thread-based multitasking. Multithreading is is less costlier than multitaskings as threads are easy to create then a process.
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