The Virtual Memory Concept

Virtual Memory is a cost effective solution to slake the thirst of memory hungry applications for a seamless experience with your operating system. To understand the concept of virtual memory you need a little knowledge about the memory organization and working. There are basically two types of memory you need to know. Random Access Memory (RAM) is faster but costly. Memory like hard disk is slower but relatively cheaper. Virtual memory is a stratagem to utilize the hard drive memory to achieve enhanced performance from the random access memory.

Whenever you run multiple programs/applications in your desktop, you will be working on only a portion of a particular application at an instant. Therefore it is a waste of resource to load the entire memory required for a particular application into the limited size random access main memory. In a virtual memory environment each page of a process is brought to main memory only when it is needed on demand.

Virtual Memory Block Diagram Working

Data is stored in any memory in the form of binary digits. The operating system handles memory management in the form of chunks of memory called pages. A page is nothing but a contiguous block of memory. One process might require multiple pages of memory but only a few pages might be active at a time. Virtual memory uses a technique called demand paging to effectively use the available RAM memory. Every page has an address which may be a virtual or logical address. The main memory is divided into equal size chunks called page frames and each page frame has a unique physical address. So whenever a page needs to be accessed, the operating system has to translate the virtual address into a physical address and this is done by a Memory Management Unit (MMU) with the help of mapping in a page table. The virtual address corresponding to a page is mapped to a physical address corresponding to a page frame in main memory. Whenever a page is not in memory the operating system fetches the page from hard disk in response to a page fault exception. The operating system usually makes a prediction based on past history using intelligent algorithms regarding those pages that are least likely to be needed again and places them in the hard disk.

25 comments:

Get More Healthy said...

Thanks for this info,it's very useful. Good Job, Keep it Up.

Rad said...

Wow, very nice explanation on virtual memory

Keep up the good work.

awais said...

nice dear
but write more shorter and in more simple for very beginner

Anonymous said...

Like Awais said, though it's very good! Thanks. :)

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I really enjoyed reading your post.

Waqasi said...

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sakthi said...

wish u happy new year....... good work & keep it up.....

sakthi said...

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Anonymous said...

Goood...

sakthi said...

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Techblizz said...

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RedPad said...

morning dear friend, wishing us for a great day :-D

Marvz said...

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unni said...

nice info

leelu said...

its really useful notes on virtual memory .thanks a lot..

pritamkosalage97 said...

it's really good explaination about virtual memory

Anonymous said...

Good work yaar...
Thanks for the info..

Anonymous said...

thaks a lot for the info.... it really was and is of great help for me... THANKS...!!!

Rahul Pardeshi said...

Nicely explained... Thanks dear.

shah said...

nice but explain with diagrame step-wise -step

Anonymous said...

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Anonymous said...

hmmm good work :)

Suganthi said...

It is easily understandable and very clear.... Thanks... :)

Anonymous said...

really very useful info

Anonymous said...

thanks

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