Is Data Recovery Worth Pursuing?
A Backup Article Contributed by Andrew Whitehead
Is Data Recovery Worth Pursuing?
When you discover that you have suffered some data loss, the first decision is always if data recovery is possible. The subsequent action that needs to be taken depends on the answer to this, whether it is worth attempting data recovery or whether to find a way of managing the data loss.
Decide If Data Recovery is Possible
This can be a very difficult choice, especially if you are unsure what caused the data loss. A technician may already have attempted data recovery and the effects of some remedies, Microsoft's "Checkdisk" for instance, are quite random.
The decision often becomes a commercial one of whether the information is actually worth the cost of recovery. Except in very extreme cases, the magnetization that stores the data will still be present on disc. Even in case where the computer has been burned, flooded, or crushed data recovery can still be possible, but at an extremely high price.
Types of Data and Their Effect on Data Recovery
The kind of data being recovered also affect this decision. If you can recover, for instance, 90% of all lost data, and these files are pictures you will retrieve 9 out of 10 pictures; this can be considered a success. On the other hand, if the files are database tables and only 90% can be recovered the entire database is corrupted. The higher the dependency and interaction between the data files, the worse the effects of even a small amount of missing data will be.
Is It Logical or Physical Data Recovery?
There are two distinct procedures in data recovery.
Physical data recovery is the extraction of the raw data from a damaged disc, logical data recovery means the rebuilding of damaged data files.
Pure logical data losses are usually caused by operator error. The accidental deletion of files, accidental drive formatting, or it may be from a malicious virus attack.
Physical data recovery from a drive that has failed mechanically may not need any subsequent logical reconstruction if it can be successfully repaired, though in practice many physical repairs are followed by logical reconstruction if some data is permanently lost due to damaged disc surfaces.
The Time Element in Logical Data Recovery
It is easy to underestimate the time element in data recovery, but losing data for a week is effectively losing the data forever. A single file that has been accidentally, permanently, deleted rather that being moved to the Recycle Bin or by emptying the Recycle Bin, is marked in the directory entry with E5.
This frees the associated FAT entry and the as the location of the deleted file is no longer protected by the file system those locations are available for recycling the next time the OS needs to create a new file.
The problem is that in any computer, files are continually being created. Many computer processes write to log files, and browsing even a single Website will download several files. Any of these could overwrite the deleted files making recovery much more difficult.
