differential backup

differential backup

[‚dif·ə‚ren·chəl ′bak‚əp]
(computer science)
Backup of only files that have been changed or added since the last backup.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

differential backup

(operating system)
A kind of backup that copies all files that have changed since the last full backup. Each differential backup will include all files in previous differential backups since the full backup so to restore a version of a file, you only need to search the full backup and the relevant differential backup.

Some systems support differential backup by associating an "Archive" flag with each file and setting this flag whenever the file is modified to indicate that it should be included in the next backup. A differential backup does not change this flag, whereas an incremental backup resets it.
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backup types

There are two categories of backup: system backup and file backup. System backup copies everything verbatim on the hard drive onto an external storage medium, including the operating system, applications and data. If the drive fails, the computer can be restored to its former state.

File backup copies only data files onto an external storage medium. If the drive fails, the OS and applications have to be re-installed. Following are the various types.

Full and Differential Backups
A full backup copies all selected files. A differential backup copies only files that have changed since the last backup.

Incremental and Delta Backups
When each revision of a file must be maintained, an incremental backup appends selected files to the backup medium and does not replace existing backup files. A delta backup is similar to an incremental backup but copies only the changed data within the selected file, not the entire file (it backs up the differences). See deduplication, backup software and cloning software.
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References in periodicals archive ?
Changes made while running virtual machines from backups are saved as differential backup files.
- Start a virtual machine from an ActiveImage Protector full, incremental or differential backup image.
A Wide Area Differential Backup Protection Scheme for Shipboard Application // IEEE Transactions on Power Delivery, 2006.--Vol.
Bacula Systems said that the plugins includes Delta plugin, which uses signature-based file difference, for backing up large binary files; VMware plugin, with raw level backup via NBD or SAN that removes the necessity to install a File Daemon on each guest; SAN Shared Storage plugin, which optimizes and increases tape library usage by providing shared access to tape drives; Microsoft SQL Server VSS plugin, which performs differential backup and allows restore at the database level; and Microsoft Exchange VSS plugin, that performs incremental backup and allows restore at the mailbox level.
According to the company, the software can help users to comprehensively backup network data, including schedule backup, full backup, incremental backup, differential backup into local hard drives, external hard drives, CD/DVD, tape device and other storage devices.
Under the simple recovery model database can be recovered only to a point when last full or differential backup was taken.
A full backup now takes a day less and a differential backup is speeded up each day by a few hours.
Differential Backup Method: A differential backup copies all those files that have been modified or changed since the last full backup.
• Complete, Incremental, and Differential Backup
With a more user-friendly interface and many new advanced functions like SQL and Exchange backup, and differential backup, EaseUS Todo Backup 3.0 will certainly become a multi-functional backup software.
For differential backup, the same data that was backed up on the previous differential backup plus any new changes are also backed up on the next differential backup.

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