Without an operating system, pretty much no device can work properly as it is the main component of every electronic communication device. Operating systems are known to ensure every program runs without an error. But sometimes, thrashing in the OS can take place due to the unexpected issue of page faults.
When thrashing happens, swapping is a method that will immediately be used by any programmer to solve the problem instantly.
Swapping in OS, helps to remove the page faults by swapping the required right page to the necessary memory, which in turn will cut off thrashing.
Now that we’ve got a general idea on what swapping does, let us take a brief look at its aspects, terminologies and necessities for reliable understanding.
Swapping in Operating System
Swapping in the Operating System helps to temporarily store data in the secondary memory by swapping it from the main memory. This swapping method is done to save some space in the main memory for other programs to run freely.
To understand it clearly, let us take processes like P5, P6, P7 and P8 as an example. Let us say all these processes are ready to get processed but P5 and P6 are taking huge space in the memory.
Due to this, P7 and P8 won’t have enough space to run. This is when the swapping method is approached as it swaps a block item from the main memory to the secondary memory, so that P7 and P8 will process in the main memory.
When the termination phase gets reached by the memory, then the execution becomes overdue. This is when whatever was temporarily swapped, is returned to the main memory again, so that the execution will seamlessly start.
Another important thing you need to know about swapping is that, when something gets stored in the secondary memory, it is defined as a swap space. This is because the space is used as a temporary queue to fit in data.
Moreover, when the priority of a process is extremely high, then the items with low priority will get sent to the swap space and likewise, high priority processes will be sent to the swap space if the low priority process needs to be run first.
One of the main reasons why swapping is implemented is because a CPU must always be put to its best use. When there is a block in the CPU, then the CPU won’t run.
Hence, when we swap and remove the block, the CPU will be maximally used. As a result, swapping technique is also known as memory compaction.
Furtherly, there are two core concepts in the swapping process that are namely: swap in and swap out, which are completed by Medium Term Scheduler. Let us have a quick insight regarding the concepts.
Swap-In
When we need to start the execution, the swap-in is applied as it returns the data back to the main memory from the secondary memory.
Swap-Out
When a process with a high priority needs space, swap-out takes place as it swaps the items from main memory to the secondary one, so that there will be enough space for the process to run in the main memory.
Example of swapping in os
Here is an easy example to understand the methodology of swapping. Let us say that you have a 5120 KB size of process and the swap space has 5Mbps size.
To figure out how long it will take to swap the data from main memory to the swap space, we will employ the swap-in and swap-out method.
The output can be found like,
Process size: 5120 KB
Swap space: 5 Mbps
Technically, when we convert 5 Mbps into KB, it will be 5120 as well. Thus we will divide swap space and main memory, that is,
Time: 5120/5120
Result: 1 second
So it takes 1 second to swap in and 1 second to swap-out, meaning that for the entire swapping process to get done, 2 seconds of time is used.
Pros and Cons of Swapping in Os
Swapping comes with certain disadvantages amidst the benefits it provides.
Some of the benefits that are usually appreciated by programmers are:
CPU will be put to the maximum use with the help of swapping.
With the help of swapping, there will be enough memory for a program to run.
Swapping helps to reduce time as the execution process quickly winds up.
No programs need to wait for another program to get completed as swapping enables the CPU to process multiple programs at the same time.
The RAM is also used well due to swapping.
The swap space is one of the best aspects of swapping as it provides enough memory to store data.
Swapping in OS is not expensive.
Swap in and Swap out improves the performance of the system.
Now that we checked how beneficial swapping is, there are some cons that we need to take note of, and they are:
If the power supply gets cut suddenly during a huge swapping process, then all the data will get lost and the user has to execute the swapping process once again.
There are chances of creating page faults if the swapping algorithm turns out to be weak.
Final Thoughts
Swapping in OS is a scheme used to manage memory spaces to accommodate smooth functioning of processes. Without the swapping feature, the CPU won’t be utilized well, and moreover, the programs won’t be able to run smoothly.
Additionally, swapping is the best way to eradicate thrashing in OS, which is a threat to the entire computer system.
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