swap file and swap parbreastion

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No. And yes

Lets start at the beginning

'swap' (more correctly, 'paging') is a method of managing real memory that permits the OS toappearto have more memory than it really does. The excess memory is emulated on a storage medium (say, disk), and the OS provides mapping logic to move blocks of data between real memory and this storage media as required by the demands of the programs executing at the time.

So, all the OSneedsis access to some storage medium in order to implement 'swap'. Well, the OSdoeshave access to storage medium, in multiple forms.

It has direct access to the underlying hard drive, and can take a portion of the hard drive for it's 'swap' use. This strategy is called 'swap parbreastion', and requires that you pre-define the size and location of the disk storage before you begin using it as swap.

The OS also has access to files recorded on the hard drive, and can use a file to store the swap space. This strategy is called 'swap file', and while it does not require preallocation, it does add extra overhead as the OS has to go through both disk I-O (like 'swap parbreastion') *and* file I-O to access the swap data.

Therecommendedmethod in Linux is a swap parbreastion, as it has less overhead than swap file access. However, Linux supportsbothswap parbreastion and swap file as swap storage. MSWindows, on the other hand, only uses swap files.

HTH - -- Lew Pitcher

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