Disk image overview

Disk image overview

Definition

Disk Image is a copy of your logical drive or physical device that is stored in one file. This can be useful when you want to backup the contents of the whole drive, and restore it or work with it later. Before you start recovering the deleted files, it may be a good idea to create a Disk Image for this drive, if you have enough space at another drive. Why? Because if you do something wrong while recovering the files (for example, recovering them onto the same drive could destroy their contents), you still will be able to recover these deleted files and folders from the Disk Image that you have wisely created.

Active@ UNDELETE provides extensive functionality to operate with Disk Images. You can create image of either Logical disk, Device or Partition. Save it as one large file or split on image chunks with size you prefer for later use.

When you creating Disk Image, it stores in at least two files: one is Configuration file with file extension .DIM and the second - actual image body file. If you decide to save disk image chopped on peaces (chunks) then image body files can be as many as its required to save data.

Here is an example: If you save a raw disk image with the name MyImage, the application creates a file named MyImage.dim. This is the configuration file. Data is stored in a file named MyImage.dim.001. If more than one file is created, the next file is named MyImage.dim.002, and so on. The data file can be split in several files – chunks that can be useful if you want to save the Disk Image on a CD or Data DVD.

When to use Disk Image

Raw disk images are very helpful in a data recovery. Here are some reasons why a raw disk image can be used for data recovery:

• Data recovery technologies are based on searching the unused space on a partition for traces of deleted, lost or damaged files and folders. So-called "unused space" on a partition is not recognized by the file system and is not saved to a regular disk image. However, this space does contain valuable data information and it is saved to a raw disk image.
• The uncompressed raw disk image file contains a sequence of sectors that is unchanged from the original. There are no headers or other application-specific identifiers added. As a result, the raw disk image can be viewed by any data rescue software as a mirror of your drive. If the integrity of the data on your live disk is questionable, you may want to experiment with the data on the partition image instead.
• If file size is an issue, a compressed raw image may be used. Active@ UNDELETE is an example of data recovery software which can work with both compressed and uncompressed raw images.
• Raw images have no regard for the file system type. During the raw disk image recording process, all sectors are backed up. An image of any partition can be restored by using Active@ Disk Image software.
• If you want the data from a file to be restored from the disk image to the same exact location as they were before, then use a raw disk image. A regular image saves all current data but restores files to different sectors, allowing the partition to shrink or grow, depending on the size of the replaced file. In a regular situation, you should not be concerned about partition size. If the partition size is important, however, a raw image is the solution.

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