What is Virtual Memory?
Virtual memory is a technique used by the operating system to make it seem like there is more memory available than there actually is. It does this by using space on a secondary storage device, like a hard drive, to store data temporarily. This allows programmers to write programs that require more memory than what is physically installed on the computer.
What is Job Pool?
In a batch processing system, a job pool is a place where different jobs are stored and wait to be processed. These jobs stay in the pool until all the necessary resources are available for them to be executed. The job pool decides the order in which the jobs are processed, based on when the required resources become available.
Difference Between Virtual Memory and Job Pool
Differences between Virtual Memory and Job Pool are as follows :
| S. No. | Virtual Memory | Job Pool |
|---|---|---|
| 1. | Virtual memory is a memory management technique that creates an illusion of infinite memory for users. | A job pool is a program in the operating system that stores newly created processes while they wait for their respective resources. |
| 2. | It makes it seem like we have a large memory when we are actually using only a portion of it. | The job pool stores newly created processes, which wait for resource allocation before execution. |
| 3. | Virtual memory represents the CPU-generated address virtually. | The job pool is where the long-term scheduler selects the order in which jobs will be executed. |
| 4. | Virtual memory is not required if infinite memory is not needed during the process of loading from the hard disk to the main memory. | The job pool is always necessary to store newly created processes during the process loading from the hard disk to the main memory. |
| 5. | For execution, a part of the process needs to be in memory. | The job pool stores newly created processes, waiting for the required resources. |
Advantages of Virtual Memory
- Memory allocation is cost-effective.
- Managing logical partition workloads with the CPU improves efficiency.
- Larger applications can run simultaneously.
- There is no need to worry about external fragmentation. Memory isolation enhances security.
- Automatic data movement is feasible.
- Users are relieved from installing memory modules when RAM space is full.
- It has a larger capacity for addresses, similar to the main memory.
- Executing a specific portion of a program whenever needed is faster.
Advantages of Job Pool
- When one task is finished, the next job from the job spool starts running automatically without needing any input from the user.
- The operating system releases memory once a job has been completed successfully.
- The processing order of tasks is determined by either a first-come, first-served basis or by their priority, depending on how they were received.