Memory and Virtual Memory Management

What is Memory Management?

One of the main functions of Operating systems is Memory Management. Memory Management may be defined as the process of managing the optimal use of main memory that is RAM (Random Access Memory). RAM is much faster than hard disk. So RAM is used to store data and instructions temporarily while they are being executed by CPU ( Central Processing Unit or PROCESSOR ). CPU can get data and instructions from RAM much faster that from hard disk.

As we know CPU is a very very fast device. It may execute billions of instructions per second. CPU will have to wait for data and instruction from hard disk because getting data from hard disk is very slow. That is why RAM is used. So data and instructions needed for execution are brought into main memory that is RAM first. Now RAM provides data and instructions to CPU rapidly.

What is Memory Management and virtual memory management

Operating System allocates the required memory are in main memory to programs that are a candidate for execution. The allocated memory area will be de-allocated when the program will finish execution.

What is Virtual Memory?

Some times, main memory that is RAM is not enough to run larger programs. In this case, some operating systems apply the technique of VIRTUAL MEMORY to overcome the problem of small RAM.

The operating system uses a particular area of hard disk as additional RAM (virtually). The most wanted part of the program in execution may be kept in RAM while the remaining part of that program may on the particular part of the hard disk. This is called Virtual Memory. The area of hard disk used for virtual memory is called a SWAP file. The Swap file is used to exchange data and instructions of a running program between RAM and Hard disk.

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Explain different types of storage devices

Topic: Explain different types of storage devices in Computer systems Storage Devices Storage devices are used to store data and instructions permanently. Storage devices are also called secondary storage devices / backing storage devices / external storage devices or auxiliary storage devices. Examples of storage devices include Hard Disk, CD and DVD etc. Why Secondary Storage Devices are Used? Secondary storage devices are used because: Primary memory(RAM) is volatile and temporary. When computer is switched off, all data in ram is erased. Storage devices can store large amounts of data and instructions permanently whereas Primary memory has less capacity of storing data. Types Of Storage Devices There are three main types of storage devices: Magnetic Tape Magnetic Disk Optical Disk Flash Memory storage devices 1. Magnetic Tape Magnetic tape is the oldest storage device. It is made of plastic coated with m...

Explain Different Types Of Output Devices

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Types Of Scanners Input Device

Scanner / Optical Scanner A scanner is an input device for computer. It can scan any printed document with text as well as images. It will : Read any printed paper or picture, Convert text or images into digital form Saves this converted digital file into computer storage for later use Uses Of Optical Scanners You can scan your documents or pictures to: Store into computer memory. To save lot of effort and time because if you type the whole text on printed page, it will take effort as well as time). Show image or text on computer screen or on a multimedia projector's screen. In addition, you can send this scanned document or image to your friends all over the world with the help of Internet & Email. You can publish the scanned documents or images on your website or blog. You can apply online and send the scanned images of your academic documents in any part of the world within minutes. If your scanner supports OCR - Optical Character Recognition, you can scan a page...

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