Data Backup Glossary (Letter C)

An interface standard for the connection of storage devices and hosts in consumer electronic devices such as mobile and handheld devices. One of the primary goals of the standard is to standardize connections for small form factor hard disk drives such as one-inch microdrives. The standard is maintained by CE-ATA Workgroup.

Also called a data center chiller, a chiller is a cooling infrastructure used in a data centers and industrial facilities. A chiller cooling system removes heat from one element and deposits it into another element. In large data centers, the chiller is used to cool the water used in heating, ventilation, and air-conditioning units. Due to the amount of heat produced by many servers and systems in a data center, chiller cooling systems are operational around-the-clock. As such, a large percentage of the electricity consumed in a data center is used by the chiller.

Cloud storage
The delivery over a network of appropriately configured virtual storage and related data services. Typically, cloud storage hides limits to scalability, is either self-provisioned or provisionless, and is billed based on consumption.

Cloud-connected storage solutions
Next-generation data protection deployed in seamless combination—on-premise and cloud, licensed software and hosted services—to optimize performance, availability, and affordability.

Acronym for computer output to laser disk. The storage of data on optical disk, such as CD-ROMs. Storing large volumes of data on laser disk, as opposed to microfiche or microfilm, lets the user access and search for this information on a computer, avoid the duplication and security costs of protecting physical documents or film, and more readily distribute information.

Cold standby
A method of redundancy in which the secondary (backup) system is only called upon when the primary system fails. The system on cold standby receives scheduled data backups, but less frequently than a warm standby. Cold standby systems are used for non-critical applications or in cases where data is changed infrequently.

CompactFlash (CF)
Often referred to as a CompactFlash or CF card, CompactFlash is a very small removable mass storage device that relies on flash memory technology, a storage technology that does not require a battery to retain data indefinitely. CompactFlash cards can support 3.3V and 5V operation and can switch between the two, in contrast to other small-form factor flash memory cards that can only operate at one voltage. CompactFlash applications include PDAs, cellular phones, digital cameras, and photo printers.

The state of being in accordance with a standard, specification, or clearly defined requirements, including legal requirements. In IT, the “compliance market” is centered around storage and systems that support the retention and discovery of data as required by law or regulation.

Compound document
An electronic document comprising more than one type of file. For example, a text file and image file.

Compressed sensing
An alternative theory to Nyquist’s Law that indicates signals and images can be reconstructed from fewer measurements than what is usually considered necessary. In contrast, Nyquist’s Law states that a signal must be sampled at least twice its highest analog frequency in order to extract all of the information. Also called compressive sampling.

The process of encoding data to reduce its size. Lossy compression (compression using a technique in which a portion of the original information is lost) is acceptable for some forms of data (for example, digital images) in some applications. However, for most IT applications, lossless compression (compression using a technique that preserves the entire content of the original data, and from which the original data can be reconstructed exactly) is required.

Compressed footprint
Amount of space consumed after compression has been applied to the data set. In a backup solution, compressed footprint refers to the amount of space being utilized by the backed-up data.

Content-addressed storage
Content-addressed storage (CAS) is an object-oriented system for storing data that is not intended to be changed once it is stored (for example, medical images, sales invoices, and archived e-mail). CAS assigns a unique identifying logical address to the data record when it is stored. That address is neither duplicated nor changed in order to ensure that the record always contains the exact same data that was originally stored. CAS relies on disk storage instead of removable media, such as tape.

Continuous data protection
Also called continuous backup, continuous data protection (CDP) refers to backing up computer data by saving as an automated function a copy every time changes are made to that data. It allows users to restore files that are corrupted or that have been accidentally deleted back to any point in time before they were lost.

Cumulative incremental backup
The backup of all data files that have been modified since the last backup.