There are mainly three types of backup.

1. Full backup or Normal backup. This backs ups the entire contents including the systemstate data of the server from where the backup is being run. you have the option to choose this. After backup is done, the attribute of the backed up file/folder is reset.

2. Incremental backup - This backups up files and folders that have been modified or created after the previous backup. After this backup, the attribute is again reset.

3. Differential backup - This backs up files and folders that have been modified or created after a previous full or incremental backup. The difference here is that the attributes are not reset. Hence every time it backups all the files whose attributes have not been reset or changed.

The Diffrent types of back ups are

Normal

Full

Incremental

Diffrential

Normal—Backs up the files you select, and marks the files as backed up.

Incremental—Backs up the files that changed since the last backup, and marks the files as backed up.

Differential—Backs up the files that changed since the last backup, but doesn’t mark the files as backed up.

Copy—Backs up the files you select, but doesn’t mark the files as backed up.

Daily—Backs up the files that changed that day, but doesn’t mark the files as backed up.

When you backup files, means that you make a safe copy of the file. So when the original data is corrupted , and if there is a backup of that original data, we can retrieve that original information.Kool right, so therz no loss of data. Thats why its been used in almost all the organizations.

Backup devices are:

Floppy drives, LS-120 drives, ZIP drives & Jaz drives.

Different types of back up are: incremental backup, differential backup, network backup and normal backup.

Full: Full backup means backing up everything.

Incremental: Incremental backup means backing up everything that has
changed since last full backup.

Differential: Differential seems to be another name for incremental.

Network: Network backup usually means backing up a client to a backup
server, this means the client sends the files to the server and the server
writes them to backup medium.

Dump: Dump backups are not ordinary file by file backups. The whole
disk partition or file system is "dumped" to the backup medium as is. This means
it is also necessary to restore the whole partition or file system at one go.
The dump backup may be a disk image, which means it must be restored to a
similar disk with same disk geometry and bad blocks in same places.

Level 0 -- 9: Level 0 to 9 backups are a finer grained version of
incremental backups. Level N backup means backing up everything that has changed
since a same or lower lever backup.