A back up is created by the process of disk imaging. In case of a computer crashing down a backup provides the user to reinstall all the software and configuration settings that have been lost up until the time that the duplication was made. A differential backup is one that seeks to overcome the gap between the time when the actual back up was made. This means that it contains those files that have changed or been added since the time the last full backup was made.
The differential backup has obvious advantages. The fundamental advantage that it offers the user is that it shortens the restore time as compared to the full back up or the incremental backup. Even differential backups have their limitations. Repeated usage of differential backups greatly increases their size which may even exceed that of the full backup.
It is important to understand the difference that exists between differential and incremental backups. Differential backup in its essence provides a middle ground where it backs up all the files that have changes since the time of the last full back up. On the other hand incremental backup accounts for the files that have been modified. To simplify; differential backup will account for anything and everything that has changed since the last full backup.
It is also true that a differential backup is restored much faster than an incremental backup. This is mainly because it requires only back up container files. These files are the latest full backup and the latest differential. The catalog file has all the information stored in it which is used to determine whether each file has changed since the time of the last full backup.
Differential backups should be used if the user has plenty of time to perform the backups. The obvious benefit of using differential backups is the fact that it only requires two files to perform the complete restore. The major downside of using differential backup is that you will end up loading files that were already contained in the earlier backups but are not the ones that have been recently modified.
Speed is the most obvious advantage of using differential backup. The whole process is umpteenth times faster than performing a full backup plus you require only two files to perform the process.
Differential backup does not come without its disadvantages though. For instance it is much slower than restoring your computer from a full backup. The backing up process is generally slower than incremental backup. You will also require a larger storage space even though they will be contained in two files. Furthermore repeated use of differential backup will make it grow to a size larger than the full version.
To summarize we can understand that differential backup comes with its share of advantages and disadvantages. One needs to analyze the particular situation of the computer and the requirements of the time and then utilize it accordingly.