What is SWAP?

Jean updated on Sep 17, 2019 to Resource | How-to Articles

Summary

What is SWAP? Data Recovery Wizard Free Edition can easily recover deleted, lost and inaccessible files or folders from SWAP partition.

To replace pages or segments of data in memory. Swapping is a useful technique that enables a computer to execute programs and manipulate data files larger than main memory. The operating system copies as much data as possible into main memory, and leaves the rest on the disk. When the operating system needs data from the disk, it exchanges a portion of data (called a page or segment ) in main memory with a portion of data on the disk.

DOS does not perform swapping, but most other operating systems, including OS/2, Windows, and UNIX, do.

Swapping is often called paging or Virtual memory.

(1) Windows example
Virtual memory has been a feature of Microsoft Windows since Windows 3.1 in 1991. 386SPART.PAR (or WIN386.SWP on Windows 3.11 and Windows for Workgroups) is a hidden file created by Windows 3.x for use as a virtual memory swap file. It is generally found in the root directory, but it may appear elsewhere (typically in the WINDOWS directory). Its size depends on how much virtual memory the system has set up under Control Panel - Enhanced under "Virtual Memory." If a user moves or deletes this file, Windows will BSoD (Blue Screen of Death) the next time it is started with "The permanent swap file is corrupt" and will ask the user if they want to delete the file (It asks whether or not the file exists).

Windows 95 uses a similar file, except it is named WIN386.SWP, and the controls for it are located under Control Panel - System - Performance tab - Virtual Memory. Windows automatically sets the page file to be 1.5 x physical memory. This page file is located at C:\pagefile.sys on all NT - based versions of Windows (including Windows 2000 and Windows XP). If you run memory intensive applications on a low physical memory system it is preferable to manually set the size to a value higher than default. Additionally, fixing the size of the swap file will prevent it from being dynamically resized by Windows. This resizing causes the swap file to become fragmented, resulting in reduced performance. This page file cannot be defragmented with Windows' built-in defragmenting tools, such as ntfsdefrag.

(2) Virtual Memory in Linux
In Linux operating system, it is possible to use a whole partition of the HDD for virtual memory. Though it is still possible to use a file for swapping, it is recommended to use a separate partition, because this excludes chances of fragmentation, which reduces the performance of swapping. A swap area is created using the command mkswap filename/device, and may be turned on and off using the commands swapon and swapoff, respectively, accompanied by the name of the swap file or the swap partition.

In order to additionally increase performance of swapping, it is advisable to put the swap partition at the beginning of the HDD, because the transfer speed there is somewhat higher than at the end of the disk.

There were also some successful attempts to use the memory located on the videocard for swapping, as modern videocards often have 128 or even 256 megabytes of RAM.

SWAP Drive Data Recovery Software

EaseUS Data Recovery Wizard Free Edition, compatible with Windows 2000/XP/2003/Vista/2008/Windows 7, can recover lost files due to deletion, format, raw partition, virus attack, system crash etc. from SWAP Drive, external hard drive, hardware RAID, hard drive, USB drive, SD card, memory card, etc.

 
 

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Frequently Asked Questions

1. Why choose EaseUS Data Recovery Wizard?

"EaseUS Data Recovery Wizard is the best we've seen. It's far from perfect, partly because today's advanced disk technology makes data-recovery more difficult than it was with the simpler technology of the past, but it's fast and efficient..."PCMag

"The first thing you'll notice about EaseUS Data Recovery Wizard Pro is that its interface is very clear and uncluttered, with only a small collection of self-explanatory controls. You won't find lots of extra options hidden in a system of hidden menus, either; what you see really is what you get."techradar

"Recover lost files, even after deleting a partition or formatting your drive."Macworld

2. Why cannot I recover 2GB data for free?

It is recommended to check the version installed is Free or Trial because they are different versions.

Trial has data preview function but cannot save any files, while the Free version enables to recover 2 GB files. The default free space is 500 MB and you may share the product on social media to get another 1.5 GB.

3. Why cannot the recovered files be opened?

A file is saved as 2 parts on the storage device: directory info (which is comprised by file name, time stamp and size info, etc.) and data content.

If the files with original file names and folder structures cannot be opened, one possible reason is the corrupted directory info. There is still a chance to recover the data content with the RAW Recovery method in our software.

4. Why isn't it suggested to recover the files back to the original drive?

The storage structure of the lost files would be altered or damaged by any changes on the drive. If you save the recovered files back to the same drive, the original data structures and data content would be corrupted or overwritten, which causes permanent data loss. So you should prepare another disk to save the files.

5. How can I check whether my data is recoverable or not before purchase?

The Free version helps you save 2GB files to better verify the recovery quality of our product before purchase.

6. How long does it take to scan the drive?

It strongly depends on the capacity of your hard drive and the performance of your computer. As reference,most drive recoveries can be completed in around 10 to 12 hours for a 1-TB healthy hard drive in general conditions.

About Data Recovery Wizard

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