Glossary

Here is what the encyclopedias say about the terms mentioned at our website to make you get to know backup and synchronization processes better.

File Synchronization

File synchronization (or 'synching') in computing is the process of making sure that two or more locations contain the same up-to-date files. If you add, change, or delete a file from one location, the synchronization process will add, change, or delete the same file at the other location.

File synchronization may be one-way or two-way. In a one-way sync, also called mirroring, files are copied only from a 'source' location to a 'target' location, or locations, but no files are copied back to the source location. In two-way sync, files are copied in both directions, keeping the two locations in sync with each other. The term synchronization is used in this article to mean exclusively two-way synchronization, in contrast with 'mirroring'.

File synchronization maintains the same version of files on multiple locations, normally directories on a computer or removable storage devices such as USB flash drives. In other words, when two locations are synchronized, the most current version of a file is available at both locations, regardless of where it was last modified. File synchronization is useful for mobile workers, or others that work on multiple computers.

It can also be used for backup purposes, although it is not ideal for this. Although it is possible to synchronize directories manually, using a software tool is both faster and less error prone.

File Backup

Backup refers to making copies of data so that these additional copies may be used to restore the original after a data loss event. These additional copies are typically called "backups." Backups are useful to restore files after they have been accidentally deleted or corrupted. Backups are typically that last line of defense against data loss.

Types of backup:

1. Full + Incrementals

A Full + Incremental repository aims to make storing several copies of the source data more feasible. At first, a full backup (of all files) is taken. After that an incremental backup (of only the files that have changed since the previous full or incremental backup) can be taken. This model offers a high level of security that something can be restored and can be used with removable media.

2. Full + Differential

A full + differential backup differs from a full + incremental in that after the full backup is taken, each partial backup captures all files created or changed since the full backup, even though some may have been included in a previous partial backup. Its advantage is that a restore involves recovering only the last full backup and then overlaying it with the last differential backup.

3. Online Backup

Backing up via the internet to a remote location can protect against some worst-case scenarios such as fire, flood, earthquake or nuclear strike which would destroy any backups in the immediate vicinity along with everything else.

Web Publishing

Creating a Web site and placing it on the Web server. A Web site is a collection of HTML pages with the home page typically named INDEX.HTML. Web sites are designed using Web authoring software which provides a graphical layout capability or by hand coding in HTML or both. Distributing the site requires copying the resulting HTML pages and graphic elements into the appropriate directories on the server.

Data Compression

Various schemes can be employed to shrink the size of the source data to be stored so that uses less storage space. Compression is frequently a built-in feature in backup software.

Password Protection

High capacity removable storage media present a data security risk if they are lost or stolen. Protecting the data on these media with passwords can mitigate this problem.

Scheduling

Using a Scheduler can greatly improve the reliability and consistency of backups by removing part of the human element. Many backup software packages include this functionality.

Log

A record of computer activity used for statistical purposes as well as backup and recovery. Log files are written by the operating system or other control program for such purposes as recording incoming dialogs, error and status messages and certain transaction details. Start and stop times of routine jobs may also be recorded.