Glossary of Terms

# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


See CIF.
See CIF.
See CIF.
1Gbit/second Ethernet - 1Gb Ethernet - 1Gb IP SAN -
1Gb iSCSI SAN - 1GbE
A one gigabit per second rate of data transfer, using Ethernet protocol. Typically, referred to as 1Gb or 1GbE, this is the standard interface speed of many iSCSI or IP SAN solutions.
2Gbit/second Ethernet - 2Gb Ethernet - 2Gb IP SAN -
2Gb iSCSI SAN - 2GbE
A two gigabit per second rate of data transfer, using Ethernet protocol. Typically, referred to as 2Gb or 2GbE, this is double the standard interface speed of many iSCSI or IP SAN solutions.
10Gbit/second Ethernet - 10Gb Ethernet - 10Gb IP SAN -
10Gb iSCSI SAN - 10GbE
A ten gigabit per second rate of data transfer, using Ethernet protocol. Typically referred to as 10Gb or 10GbE, this is up to ten times the standard interface speed of many iSCSI or IP SAN solutions.
704x240 pixel resolution.
704x480 pixel resolution.


Alternating current, known most commonly as AC, is typical electrical service, such as 110/120v.
See "American Correctional Association"
Access Card
An access card is the user-specific component of many access control systems. The access card, or dongle, is a specially coded card that features a magnetic stripe, active or passive proximity, BF (Barium Ferrite) or similar technologies to interface with an access control system. An employee may be issued an access card to enable access through a specific door or doorways, or provide other access functionality.
Access Code
An access code may be alphanumeric or other coding string that provides access to a system, software program, computer or other electronic device, and operates similarly to a password.
Access Control
A type of identity management and facilities access control system common in physical security.
Access Point
In a security-protected system or area, an access point is a point of entry in to the system, device or area. Typically a component of an access control system.
In a mechanical or electronic system, a component or device that is powered and/or capable of movement or activity is ";active";. Opposite of ";passive";.
Microsoft Windows operating systems often support ActiveX in order to transfer or share data between applications. Legacy devices in security systems, such as DVRs, as well as some video management software systems, often use ActiveX to remotely view surveillance cameras.
Activity Detection
Networking and security devices, such as multiplexors, use activity detection technology to trigger alarms or activities in recording, alerts, notification, etc.
Analog to Digital Converters are used to transfer an analog image or file, such as generated by an analog video surveillance camera, into a digitally formatted file that can be stored on a hard disk or other electronic media. Most DVR systems are a combination of a specialized PC system coupled with an ADC.
Advanced Video Coding
Compression techniques used in H.264, with profiles ranging from baseline through to high profile (HD).
A technology used in surveillance cameras to increase or cap signal strength in low light conditions or changing light conditions where light levels either increase or decrease.
See Auto iris.
Alarm Input
In security devices, particularly in surveillance cameras, an alarm input can be used to provide increased capabilities, such as to detect a door opening, movement, IR, etc.
Automatic level control is found in many surveillance cameras to increase or improve detail in over- or under-illuminated areas.
Mathematical calculations, used in surveillance as part of reliable digital compression technology to reduce the size of the picture or file, and allow recreation at orginal format.
Ambient Light Level
In photography, ambient light is the amount or degree of background light. In security systems, the ambient light level is often part of the calculation for surveillance camera settings.
American Correctional Association
The American Correctional Association (ACA) is the oldest and largest international correctional association in the world.
Analog camera
Analog cameras when used for video surveillance or other recording applications typically integrate with encoders (see "Encoders") over coax cable.
Analog Signal
Legacy surveillance systems typically transmit an analog signal from camera to recording device, such as an encoder.
Analog Surveillance System
Analog video surveillance cameras and VCR (tape) or DVR-based recording, typically being replaced with IP-Based Video Surveillance Systems in new deployments.
Angle of View
The viewing angle or "angle of view" is the angular range available when a particular camera type or image size is selected. The angle of view increases in width as the focal length of the lens or camera is decreased.
For security systems, an annunciator is a signaling or notification device that can trigger a response or send an alert.
In cameras, the aperture is a lens opening, which determines the amount of light that reaches film or electronic sensor.
In an IP (Internet Protocol) digital network, typically Ethernet, ARP is a common method of obtaining a device (or host's) address on that network.
ASIS or ASIS International
The American Society of Industrial Security (ASIS) International. Leading physical and IT security practitioner organization, with many key subcommittees including the ASIS Physical Security Council and the ASIS IT Council. For information on ASIS, go to
Aspect Ratio
In an image, the aspect ratio is the mathematic difference and relationship between an image height and width. In digital technology, aspect ratio refers to the shape of individual pixels in an image.
Auto flip
A surveillance camera technology that can be used to change the viewpoint of the device automatically, such as when mounted on a wall or on a ceiling.
Auto Gain Control
See AGC.
Auto iris
A technology for surveillance cameras that improves image quality in variable light conditions, protecting the camera's CCD sensor from strong direct light which can cause damage.
Automatic White Balance
An automatic camera adjustment to modify color settings for improved and consistent quality of the white portion of images.
See "Advanced Video Coding".


The H.264 compression standard supports B-Frames, or bi-directional frames, for predictive video imaging. B-frames deliver faster imagery and smaller files sizes for compressed video, nearly 50% less than MPEG-4 files. B-frames are, however, more processor intensive, leading to heavy CPU loads on cameras and recording devices.
Back Focus
The back focus is used in zoom lenses on cameras, allowing the camera to be focused as the image sensor moves in relation to the lens.
Back Lash
In pan-tilt-zoom (PTZ) cameras, sometimes the camera's movement cannot be stopped instantly on demand, typically requiring adjustment.
Baluns, an acronym for "Balanced/UnBalanced", is a device that converts video or audio signals from one mode to the other, typically measured in impedance.
In networking, bandwidth is the amount of digital "pipe" or capacity that a signal can transmit or receive. Multiple devices transmitting on a network can potentially degrade or consume all available bandwidth, reducing system throughput and overall performance.
Basic Local Alignment Search Tool (BLAST)
BLAST finds regions of local similarity between sequences. The program compares nucleotide or protein sequence databases and calculates the statistical significance of matches. BLAST can be used to infer functional and evolutionary relationships between sequences as well as help identify members of gene families.
Biometrics in security systems are typically fingerprints, eye scans, voice patterns, etc., and are used as an authentication technique in access control.
In computer systems, the smallest unit of measure that can be stored. It is set as either '0' or '1'.
Blade Server
A blade server is essentially housing for a number of individual minimally-packaged computer motherboard "blades", each including one or more processors, computer memory, computer storage, and computer network connections, but sharing the common power supply and air-cooling resources of the chassis. The idea is that by placing many blades in a single chassis, and then 19-inch rack - mounting them, systems can be more compact and powerful, but less expensive than traditional systems based on mainframes, or server farms of individual computers.
Also known as "Back Light Compensation", BLC is used in cameras to increase or improve detail of imagery in dark area of an otherwise bright image, or when a particular light source overpowers the rest of the image
When brightness increases, a defocused or overbright area can appear on imagery, which can be decreased by some surveillance cameras.
Blu-ray, Blu-ray disc, or BD is an optical disk of high density used for digital media and high-definition video storage.
A bitmap file or "bumped" file is a Microsoft Windows-native bitmapped graphical image.
Fitting used to connect coax cable to surveillance cameras and equipment.
BNC Connector
See BNC.
Bits per second (or bps) is a measurement of data transmission speed.
Brick Server
A brick server is a compact computer server module without a chassis that can come in various processor, RAM, I/O, and storage configurations and is designed to fit into rack locations similar to those for blade servers. Like blade servers, brick servers are intended to fit in multiple numbers into a rack that provides a shared backplane. Blade and brick servers allow more servers to be contained in the same floor space than the more conventional pizza box servers with a chassis. SMBs are typically users of brick servers, while larger organizations and enterprises typically outgrow them quite quickly and need a more structured and efficient model for storage consolidation, backup and recovery, and other solutions.
Bridging is when one high impedance video line is paralleled to a video source or device.
A broadband network is a digital transmission system capable of carrying digital data at high speed between two or more devices.
Bullet Camera
A bullet-shaped surveillance camera, narrow and small in size and designed for tight or compact spaces.
Data and images can be "burned" to a DVD or CD to create a copy of the material. In computer monitors, burn can occur when an image remains on screen for extended periods of time. Screen savers are often used as one way to turn off an image to avoid burn, as is autodimming. In camera terms, burn can also occur when an image is frozen onto an image of a camera or monitor device.
Bus Network
Transmission from the computer or device "bus" to other devices. In a computer, the bus is the main interface area for cards or other devices to be plugged in to communicate with the CPU or other computer resources.
8 bits (see Bit).


Older surveillance cameras often used a C mount with a flange of 17.5mm.
In surveillance or computer terms, a cable is an insulated wire that connects two or more devices together.
Cable Tray
A device to control the layout of cabling in a logical manner.
1/16th of a video monitor's viewing area.
A measurement of luminous intensity.
CapEx or CAPEX
Capital Expenditure. A financial term, for expenditure of financial capital or budgeted funds for a specific acquisition or purchase.
Cat 5
Cat 5 (or Category 5) cabling is a multipair cable that consists of twisted pair conductors, and used for IP data transmission. For Ethernet, Cat 5 cable supports 10 Megabit per second through to 10 Gigabit per second. Cat 5 E is "enhanced" Cat 5 cabling, part of the EIA/TIA 568A standard, and is used in most new installations.
Charged Coupled Devices, commonly used in digital still and video cameras are key components of digital surveillance systems.
Closed Circuit Television or Closed Circuit TV is a television broadcast technology with video cameras transmitting in a closed environment, such as a corporate campus, private network or only using point-to-point wireless links rather than openly broadcasting. Typical uses are also for video surveillance systems for public and private institutions and locations.
Continuous Data Protection is a form of computer backup protection that automatically saves all changes made to data, so that the administrator can restore any lost or corrupted data to a specific point in time.
The Common Intermediate Format is a video standard, designed to be easy to convert to NTSC or PAL standards. CIF has a resolution of 352x288 pixels per second; SQCIF has a resolution of 128x96; QCIF has a resolution of 176x144; 4CIF has a resolution of 704x576; 16CIF has a resolution of 1408x1152.
Chief Information Officer, typically responsible for all information technology hardware, software, infrastructure and people of an enterprise or organization.
Chief Information Security Officer, typically a hybrid between the two positions of CIO and CSO.
A CLI or Command Line Interface is a text-based administrator tool to manage a software or hardware system.
In computers, clustering is the use of multiple computers, typically PCs or UNIX workstations, multiple storage devices, and redundant interconnections, to form what appears to users as a single highly available system. Cluster computing can be used for load balancing as well as for high availability. Advocates of clustering suggest that the approach can help an enterprise achieve 99.999 availability in some cases. One of the main ideas of cluster computing is that, to the outside world, the cluster appears to be a single system.
A common use of cluster computing is to load balance traffic on high-traffic Web sites. A Web page request is sent to a "manager" server, which then determines which of several identical or very similar Web servers to forward the request to for handling. Having a Web farm (as such a configuration is sometimes called) allows traffic to be handled more quickly.
Acronym for Complementary Metal-Oxide Semiconductor. Common programmable chip technology. In video surveillance, used in CCD technology.
Coax or 'coaxial' cable is a standard for high frequency transmissions, used for analog signal transmission (some data networks as well as CCTV cameras, cable television systems, etc.).
Coax Cable
See coax.
Codec & CODEC
Short for Encoder/Decoder, a codec is a hardware device or component that performs either or both analog-to-digital conversion (ADC) and digital-to-analog (DAC) conversion. See DAC, ADC, and Encoder.
CODEC - Definition of how individual systems compress images into byte format, then decompress back as needed into images. A CODEC device is the platform which performs these tasks, and may support multimedia streams of data.
Composite Video
Composite video can be modulated into an RF carrier signal. It is composed of YUV, field, line, color sync, blanking pedestal and filed equalizing signals.
For video applications, compression refers to the algorithm used to compress the video data. Compression can reduce individual file size and total storage requirements. JPEG is a standard still-camera and image scheme, while MPEG is common in video.
Concave Lens
A light-diverging lens, typically with an inward curving surface.
Consumer Grade
Consumer grade components are often found in less expensive physical security and industrial video systems, such as DVRs and NVRs. These devices take their name from PC components (disk drives, power supplies, mother boards, CPUs, memory, video cards, etc.), mass marketed for IT applications and often part of the Common of the Shelf category. They are often designed for PC workloads, typically for applications like email, word processing, spreadsheets and web browsing and are growing more common in physical security applications due to low cost. Most PCs are not designed for non-stop, 24x7x365 operation and the components reflect that design architecture.
Most common consumer grade components are power supplies (typically not hot-swap capable when consumer grade) and disk drives. Consumer grade disk drives typically offer an MTBF of 1 million hours or less. In comparison, enterprise or server grade power supplies are typically cold or hot-swappable, and disk drives are typically of 1.2 million hours MTBF.
See "Storage Controller".
Convex Lens
Convex lens converge inbound light into a focal point, and the lens itself curves outward.
See "Storage Controller".
In surveillance, either physical surveillance or video surveillance, covert is the terminology behind hidden or misrepresented surveillance activity.
Central processing unit, or CPU, is the brains of an electronic device and what is the processor in a computer system.
Cross talk is interference from one electronic channel to another.
Cathode Ray Tubes or CRTs were the primary video monitor for surveillance systems since the introduction of television and video cameras. In recent years, most new implementations use LCD (Liquid Crystal Display) or Plasma screens due to lower energy use, thinner size and improved digital display quality.
CS Mount
Camera with a CS mount have a flange back distance of 12.5mm, and are effective in smaller, thinner cameras than other mounts (including C mounts).
Chief Security Officer, typically responsible for the physical and electronic security hardware, software infrastructure and people of an enterprise or organization.
CT or computed tomography is a common medical imaging technology. CT scans use a 360-degree X-ray beam to create digital images.
Chief Technology Officer, typically responsible for the strategy and vision of an enterprise or organization.


Digital-to-analog conversion, for recording digital images to analog, such as onto tape. See also ADC, Encoder.
Data Warehousing
Data warehousing (DW) is a process for building a data repository the form of a relational database, supporting web or text mining to leverage data into useful information. Organizations often use data warehousing as a competitive advantage, supporting their decision making process through comprehensive data analysis. Decision Support Systems (DSS) and Data Mining (DM) systems are key components of these solutions.
A dB or decibel, a unit of measure that measures strength of a signal or sound.
Direct current, in which electricity forms in only one direction (which differs from Alternating Current), such as in a battery.
Discrete Cosine Transform (DCT), a block-based compression algorithm, used MPEG-4 Part 2.
Direct drive is a gearless drive mechanism, found frequently in pan-tilt-zoom cameras.
In analog systems, separation of audio, video and data that were multiplexed together for transmission from the source device.
Default Gateway
The default address of the router, in IP networks for data transmission.
Depth of Field
Dependent upon the F-stop and focal length of the lens, depth of field is the difference between the nearest and farthest points in an image while clarity still exists.
DHCP or Dynamic Host Control Protocol is used by one host computer to obtain an IP address to communicate with other hosts.
Digital Camera
An electronic camera or filmless camera, often also capable of recording both images and sound. Digital surveillance cameras are rapidly outpacing their analog equivalents, and many can use standard TCP/IP and Ethernet standards, effectively eliminating distance limitations for video surveillance monitoring systems. Digital cameras typically have superior resolution than analog surveillance cameras.
Digital Image
A file which records a two dimensional image, composed of pixels.
Digital Surveillance System
See IP-based Video Surveillance System.
Digital Video Surveillance
Video surveillance systems have been in use and growing ever since the invention of the television camera, and in the 1990s analog cameras gave way to charged coupled devices (CCD) built into digital cameras. Digital surveillance networks passed into another phase with the introduction in the early 2000s of IP (Internet protocol) networks, common in most data centers, telephone companies and other related infrastructure environments.
Direct Attached Storage
Direct Attached Storage (DAS) refers to a digital storage system directly attached to a server or workstation, without a storage network in between. It is mainly used as a term to differentiate non-networked storage from SAN and NAS
The main protocols used in DAS are SCSI and Fibre Channel. Traditionally, DAS systems enable storage capacity extension for servers, while keeping high data bandwidth and access rate. Most common DAS Systems are made of one or more enclosures holding storages devices such as hard disks, and one or more controllers. Interfacing with the server or the workstation is made through the HBA (Host Bus Adapter).
DAS systems typically offer fault tolerance at every level with controller redundancy, cooling redundancy and storage fault tolerance patterns known as RAID. Entry level DAS systems most often are made of an enclosure without active components such as controllers, thus access logic and fault tolerance patterns are provided by the server HBA.
Middle and top range DAS systems provide embedded controllers. RAID management is off-loaded, and simple non-RAID HBAs can be used, lowering costs. DAS controllers also enable shared storage access, which permits multiple servers (usually no more than 4) to access the same logical storage unit, a feature that is mainly used for clustering. At this point, top range DAS systems share similarities with entry level SAN systems.
Disadvantages of DAS
DAS has been referred to as "Islands of Information". Disadvantages of DAS include inability to share data or unused resources with other servers. Network-attached storage (NAS) attempts to address this issue, but introduces some new issues as well, such as cost of storage area networks, manageability, security, and contention for resources.
Disaster Recovery
A plan for a business to restart operations after a disaster; this is especially evident in information technology; with most large computer systems containing software to limit data loss and to aid data recovery. It is believed that some companies spend up to 25% of their budget on disaster recovery plans; however, this is to avoid bigger losses.
Disk to Disk (D2D) Backup and Recovery / Disk Based Backup and Recovery
Organizations are increasing moving from tape-based backup and recovery systems to disk based backup. Instead of employing tape as the primary media, IP based SAN disks are used for higher performance, better reliability and increase cost savings.
The term "disk-to-disk", or "D2D", generally refers to disk-to-disk backup. With D2D, a computer hard disk is backed up to another hard disk rather than to a tape or floppy. D2D is often confused with Virtual Tape, but differs in that it enables multiple backup and recovery operations to simultaneously access the disk directly by using a true file system.
Typical advantages of disk-to-disk
  • Higher speed and higher capacity, relative to tape or floppy, resulting in shorter backup and recovery windows.
  • Non-linear recovery of data, enabling a specific file to be restored quicker and simpler than with tape.
  • Lower total cost of ownership due to increased automation and lower hardware costs.
Dome camera
A wall or ceiling mounted analog or IP network surveillance camera, protected and/or obscured by a transparent or translucent plastic or glass dome. Typically a PTZ (pan-tilt-zoom) camera equipped with a slip ring, which allows 360 degree full motion with non stop 24x7 movement and monitoring support when used in a professional surveillance system.
See VSA Multi-Mode.
Digital Video Disks or Discs is a common disk format for storing on inexpensive optical storage. The same size as CDs, DVDs provide many times the storage capacity. Most DVD disk are used for backups and static files.
DVD-R or Digital Video Disk-Recordable and DVD-R(W) is a recordable DVD standard. Once written, it cannot be erased.
DVD-RW and DVD-R(W) are two other recordable formats of DVD. DVD-RW can be rewritten multiple times.
Digital Video Recorders are a common recording devices for video surveillance, IPTV and video on demand. A hybrid kind of technology, DVRs are part analog and part digital. Images are analog and delivered by coaxial cable to the DVR. In the DVR, they are digitized, stored and/or viewed. When used in video surveillance applications, they are either embedded design or PC-based. PC-based DVR systems often offer more functions and features.
The DVR is used in place of VCR or Video Cassette Recorder devices use tape cassettes to record video streaming from one or more cameras onto hard disk drives. This is accomplished in PC-based systems by using a PC motherboard, power supply, one or more disk drives and an ADC or analog-to-digital converter. Most DVRs record from analog surveillance cameras. DVR professional surveillance system market share is under pressure of replacement by digital IP surveillance systems, although they continue to dominate the market at the low end (small number of camera) space.
DVR Upgrades
See "Smart CCTV DVR Upgrades".
DVS or Digital Video Surveillance
DVS or digital video surveillance systems are next-generation technology whereby the entire system is electronic or "digital" in nature, not using any analog camera technology for video surveillance needs. Also known as IPVS (IP video surveillance) or NVS (network video surveillance).


Edge Recording
Edge recording is a rapidly growing technique in video surveillance applications to store video take at an "edge" or individual location on a local device. When needed, many edge recording applications can upload the appropriate video take to another location for additional processing, analysis or retention. Sensors, analytics and intelligent devices help determine what is recorded on the edge, and what is transmitted on for further processing or retention. For more information, see CT - CT or computed tomography is a common medical imaging technology. CT scans use a 360-degree X-ray beam to create digital images.
A data cabling standard, first published in 1991, and adopted by most non-proprietary networking architectures today. Also known simply as "568A".
An encoder is a hardware device that "encodes" or renders video, audio or other electronic or analog media to another format. See DAC, ADC, Codec.
Enterprise Grade
Enterprise grade refers to OEM components or devices that are designed for higher reliability, longer service life and better quality and/or uptime.
In military applications, ESM is the acronym for Electronic Surveillance Measures. In most civilian security applications, ESM is more commonly used as the acronym for Electronic Surveillance Management.
Evidentiary Protection
See Replication & Evidentiary Protection
Exabyte or EB
1,000 petabytes or 1018 bytes.


Fat Provisioning
Traditional storage is provisioned in a "fat provisioning" model, where spaced is allocated beyond current actual needs in expectation of future growth and needs. This results in very low utilization, and potential errors in provisioning with some storage never utilized at all and other applications running out of storage unexpectedly. Fat provisioning systems are largely being replaced with newer, more advanced thin provisioning base storage solutions (see "Thin Provisioning").
Fibre Channel
Fibre Channel is a gigabit speed network technology primarily used for Storage Networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards (INCITS), an American National Standard Institute (ANSI) accredited standards committee. It started for use primarily in the supercomputer field, but has become the standard connection type for storage area networks in enterprise storage. Despite its name, Fibre Channel signaling can run on both twisted-pair copper wire and cables.
Film Resolution
See Resolution.
Video Frame Per Second. See Frame Rate.
Frame Frequency
See Frame Rate.
Frame Rate
A common term in computer graphics as well as video cameras, is measured in either hertz (Hz) or frames per second. It represents the sequential movement of images or "frames".


Gigabyte or GB
1,000 megabytes or 109 bytes.
Group of pictures.
Green IT is a broad term for the Information Technology industry's focus on reducing energy consumption and harmful environment effects while continuing to provide the high level of service and support that IT is known for by its clients. Technology such as thin provisioning (see "Thin Provisioning") and standards like RoHS (see "RoHS") are aimed at delivering green IT solutions. Reducing electrical consumption, cutting back on the requirements for heating and cooling, designing better layouts of data centers, and reducing the number of items going to the landfill by allowing systems to scale to more performance and capacity are all valid components of green IT. The Storage Networking Industry Association (SNIA) Green Initiative and The Green Grid organizations are leading much of this effort in IT.
Grid Storage
Grid Storage/Grid SAN (also known as Storage Grid) - is a method of linking independent storage nodes that are then monitored by a controlling software layer. It offers easy management, fault tolerance and access at the file and block level. Such an approach is said to reduce down costs, speed up backups and improve utilization.
A GUI or Graphical User Interface is a graphical-based administrator tool to manage a software or hardware system.


ITU (International Telecom Union) published standard, established in 1990 for video conferencing over public switched networks.
ITU (International Telecom Union) published standard, established in 1996. Designed for low bit rate data streams, it is used in video conferencing and similar applications.
See MPEG-4 Part 10) and standards like RoHS (see "RoHS".
Hi Definition
Also known as Hi Def, a video system standard that is superior to standard resolution to SD (standard definition) systems.
High Availability
A protocol and associated execution that ensures a certain relative degree of computing-system operational continuity in any downtime event.
For example: A continuously available computer system is characterized as having essentially no downtime in any given year. A system with 99.999% availability experiences only about five minutes of downtime. In contrast, a high availability system is defined as having 99.9% uptime, which translates into a few hours of planned or unplanned downtime per year.
Hybrid DVR
Hybrid DVRs are so called because unlike regular DVR systems, they can record image from both analog and digital surveillance cameras. Like DVRs, they are most often a combination PC motherboard, power supply and disk drives, with an analog-to-digital converter (ADC) to support recording of analog images to digital media, in this case hard disk drives. See also DVR.


An I-frame (Iframe or intra-frame) is a video frame that has been encoded without reference to any other frame of video. There are regular I-frames in the video stream to assist seeking within the stream. See also P-frame.
IHV - Independent Hardware Vendor, typically a computer, storage, security or systems manufacturer.
Information Lifecycle Management is software that allows systems administrators to define and manage how their data is stored and managed. Four components are common to all ILM systems: Policy; Management; Operations; Infrastructure.
Image compression
A method of reducing the size of an image for transport or storage.
Image stabilization
A technology used by surveillance camera vendors to improve image quality despite factors such as movement, wind, and vibration.
Industrial Video
Industrial video is a wide term for video surveillance used outside of more traditional video surveillance needs and requirements. Supply Chain and Quality Assurance, for example, are growing users of video surveillance, to reduce costs of live inspections yet able to ensure to a degree never possible before that manufacturing, shipping, retail and other environments are safe and secure, and meet the planned objectives of an organization. Industry video also refers to corporate video storage, such as internally produced video for training and education purposes, typically stored today on digital (disk) media. This video may be distributed via IPTV, Video on Demand (VoD) or via another form of digital distribution. As video retention increases with digital (disk) recording media replacing tape, IP cameras replacing analog, and video retention and reliability increasing, industrial video is playing a larger role in organizations ranging from HR, supply chain, sales, marketing, legal, manufacturing, shipping and other functions.
Intelligent Video or IV
Intelligent video is a term that relates to the use of video content analysis (VCA) or video analytics for video surveillance purposes. IV can be used to reduce recording needs, to notify operators of specific conditions, or to offload many other tasks the previously relied entirely upon human intervention and management.
Used in a growing number of cameras and add on devices.
Intelligent Video Surveillance or IVS
Intelligent video surveillance systems or IVS deliver "smarts" in the camera or in an add on device to the camera for use in video surveillance. Also known as smart video surveillance or smart video, may also include use of sensors, alarms and external devices.
Inter-frame coding
See video compression.
International Telecommunication Union
United Nations-sponsored standards body, supported in 185 member countries, that sets standards for global telecommunications networks. Standards identified with the designator "ITU".
Internet SCSI (iSCSI)
Internet SCSI (iSCSI) is an official standard ratified on February 11, 2003 by the Internet Engineering Task Force that allows the use of the SCSI protocol over TCP/IP networks. iSCSI is a transport layer protocol in the SCSI-3 specifications framework. Other protocols in the transport layer include SCSI Parallel Interface and Fibre Channel.
Acceptance of iSCSI in corporate production environments has accelerated now that Gigabit Ethernet is common.
Intra-frame coding
See image compression.
Internet Protocol, a set of standards for the transmission of digital data, commonly used on Ethernet (1 or 10GbE) networks for data transmission.
IP Camera
IP (Internet Protocol) cameras are digital, CCD-based video surveillance devices commonly used in physical security applications. Rapidly replacing older analog surveillance camera technology, IP cameras use Ethernet cabling or wireless technology to transmit images using IP. Also known as digital surveillance cameras, or network surveillance cameras.
IP SAN / Internet Protocol SAN / iSCSI SAN
IP SAN or iSCSI SAN are common names for IP based SAN.
IP-Based Video Surveillance System
Digital IP video surveillance cameras, based upon IP infrastructure (CAT5 or wireless).
IP-enabled devices, such as cameras, access readers, door control devices, etc., are those that are used in physical security and are able to be controlled and/or accessed via IP network technology.
Images Per Sector (ips). See "Frame Rate".
IPTV / Internet Protocol Television / Internet Protocol TV
IPTV is an television transmission protocol that is carried over IP, or Internet Protocol, networks.
IPVS or IP Video Surveillance
Internet Protocol Video Surveillance is the terminology commonly used to describe all-IP (Internet Protocol) based network architectures for video surveillance, typically deployed using standard Ethernet IP infrastructure. See also IP-Based Video Surveillance System.
Infrared or infrared light source or illuminator, undetectable by human eyes without machine assistance, lies between visible and microwave light spectrums.
IR illuminator
An infrared technology which can improve image quality in low light or no light environments, which projects an IR beam for illumination.
iSCSI Camera
See IP Camera.
iSCSI Storage
iSCSI Storage (also known as iSCSI SAN) - a Storage Area Network based on iSCSI. Building iSCSI-based Storage Area Networks (SAN) has become a less costly but worthy alternative to creating Fibre Channel-based SANs.
ISV - Independent Software Vendor, typically a software developer for computer, storage, or security applications.
International Telecommunications Union.


A common video file standard, taken from the name of the committee which established it, the Joint Photographic Experts Group after founding in 1986.
JPEG Interchange Standard
File format for JPEG.
JPEG2000 is a standard video compression codec and file format, supplanting JPEG. Using wavelets, it delivers higher compression without compromised image quality. Competing standard to the newer H.264 codec, supporting up to 16 megapixels for cameras.


Kilobyte or KB
1,000 bytes.


In video, analog cameras and devices have near-instantaneous access while IP has a latency or delay factor. For Motion JPEG (M-JEG), the latency of IP cameras if often 100 milliseconds. For MPEG, latency may grow to 200-250 milliseconds. Applications typically are able to eliminate much of the impact of latency for cameras and other devices.
Life Safety
Life safety is a physical security industry term, covering a variety of areas sometimes including fire alarms, intrusion detection, etc.
Load Balancing
Load Balancing - refers to the general practice of balancing a load. In computing, load balancing refers to balancing server traffic amongst multiple computers.
Lossless compression
Video compression type, allowing original data to be reconstructed. Types are GIF, ZIP.
Lossy compression
Video compression type, achieving 50-90% compression rate with no visible impact, such as JPEG.
A Logical Unit Number or LUN is the term for an array of disks or a drive volume, allocated to perform and respond as a single storage devices.


M-JPEG or MJPEG connects sequences of JPEG files together, a frame at a time, into a video file.
Medical Imaging
Typical new health care applications that are improving efficiency and cut costs for the medical industry, including hospitals, research centers, clinics, physicians offices and other facilities include the Picture Archiving Communications Systems (PACS) solution set, and multislice Computed Tomography (CT) scans. PACS digitally store cardiology and radiology tests, magnetic resonance imaging (MRI) results, and other large files. Multislice CTs allow faster brain scans, and can focus on thinner slices of tissue than previous CTs.
Megabyte or MB
1,000 kilobytes or 106 bytes.
1 million pixels. Used as a measurement of file size, as well as the resolution capacity of digital cameras.
Motion Compensation
Used to enable video compression, motion compensation is technology used to ensure the best image quality of moving objects in video, related to motion estimation and I-frames in consecutive frames.
Motion Estimation
As objects move in an image sequence, this technology determines vectors representing the estimated motion.
A video or graphical file standard that provides spatial compression for large files that need to be recorded in high quality. Typical variations range from MPEG-1 through MPEG-4, which is commonly used for storage at DVD-quality image rates.
MPEG License
MPEG-2 and MPEG-4, two common compression standards, are licensed technology. As such, many camera and DVR/NVR vendors are required to charge licensing fees per decoder and encoder. Go to for details.
MPEG-4 compresses across frames, resulting in a good compression algorithm. MPEG-4 can require significant CPU processing from the system performing the compression.
MPEG-4 Part 10
MPEG4 Part 10 is also known as H.264. MPEG4 Part 10 offers better compression than previous MPEG versions, using motion estimation.
MPEG-4 Part 2
An older MPEG standard, using DCT (see "DCT"). Largely replaced with MPEG-4 Part 10.
Magnetic Resonance Imaging or MRI is a type of medical imagery created by using magnetic fields.
Acronym for "Mean Time Between Failures", a common measurement for the reliability of components, usually found in evaluating disk drives. Consumer grade (also known as PC grade) disk drives typically feature an MTBF rating of 1 million hours or less; enterprise grade (also known as enterprise grade or server grade) typically feature an MTBF of 1.2 million hours or more.
See VSA Multi-Mode.
MUX or Multiplexor
A mux or multiplexor is a device for mixing and converging multiple analog or digital feeds, such as audio or video.


Network Camera or Network Surveillance Camera
Network or network surveillance cameras are common names for digital cameras used in video surveillance applications. They typically are able to connect over common network architectures, most commonly Ethernet, for image recording and often for power (see also PoE).
Network cameras may feature standard pan/tilt/zoom (PTZ) features as do many analog devices, but also may offer features such as night vision and low light recording, video analytics and megapixel image quality.
Network Security
The standards, practices, procedures and technologies used to protect an organization's corporate data network, communications and IT resources, from authorized or malicious use.
Network-Attached Storage (NAS)
Network-Attached Storage (commonly abbreviated to NAS) systems are generally computing-storage devices that can be accessed over a computer network (usually TCP/IP), rather Network-Attached Storage than directly being connected to the computer (via a computer bus such as SCSI). This enables multiple computers to share the same storage space at once, which minimizes overhead by centrally managing hard disks. NAS systems usually contain one or more hard disks, often arranged into logical, redundant storage containers or RAID arrays.
The protocol used with NAS is a file based protocol such as NFS or Microsoft's Common Internet File System (CIFS). In reality, there is a miniature operating system on the device such as DART on EMC's Celerra devices or Data ONTAP on NetApp NAS devices.
NAS devices become logical file system storage for a local area network. Thus the performance of NAS devices depends heavily on cached memory (the equivalent of RAM) and network interface overhead (the speed of the router and network cards). The benefit is that the device can become a giant neighborhood hard drive for a whole building. The disadvantage is that any constrictions in the local network will slow down the resulting access time.
NTP or Network Time Protocol is used to synchronize computer and/or security devices to a single date and time. See the NTP Public Services Project for more detail at or for public NTP services, go to
The National Television Standard Committee standards for analog television broadcast systems, adopted by the committee in 1940 and used throughout North and South America and some Asian countries (Japan, Philippines, South Korea). See PAL and SECAM.
Network Video Recorders are similar to DVR systems in that they replace older VCR technology in the recording of video surveillance images. Instead of tape media, NVRs record on digital hard disk drives. Unlike DVRs, which typically record analog surveillance camera images, NVRs generally support digital or network surveillance camera recording. Many NVRs are software-based systems that can be installed on standard servers.
Network video surveillance, also referred to as IPVS (IP video surveillance) or DVS (digital video surveillance), is a next-generation technology whereby the entire system is electronic or "digital" in nature, not using any analog camera technology for video surveillance needs.


Acronym for "Original Equipment Manufacturer". Components produced by OEMs are used in physical security, IT and similar products. A typical OEM product is the disk drive, which is manufactured by just a few major manufacturers such as Hitachi, Seagate, Western Digital, etc., and used by most PC, server, DVR, NVR and other devices.
OEM Grade
OEM grade devices often refer to higher end or more reliable components, despite the fact that most components are manufactured by OEM manufacturers. Server or enterprise grade are often considered better terms for higher quality, more reliable disk drives.
"Enterprise grade"
On Demand Learning
By employing a distributed video on demand service, remote locations or campuses can be provided with live or pre-recorded television quality broadcasts.
ONVIF is an open industry forum for the development of a global standard for the interface of IP-based physical security products. It was officially incorporated as a non-profit, 501(c)6 Delaware corporation on November 25, 2008.
ONVIF is committed to the adoption of IP-based physical security in the security market. The ONVIF specification will ensure interoperability between IP-based physical security products regardless of manufacturer.
OpEx or OPEX
Operational Expenditure, a financial calculation of day-to-day or month-to-month cost of operations or lease payment.


P-frames, or predicted frames, are motion-compensated video frames. They hold the differences between the previous frames, and are smaller than I-frames (see "I-frames").
Picture Archive Communication System.
Phase Alternating Line or PAL is a 1950s defined system for color television and still used in broadcast television. See NTSC and SECAM.
PATA or Parallel Advanced Technology Attachment is a kind of disk drive standard, mostly replaced by SATA or Serial ATA drives today in modern storage implementations. See SATA.
Petabyte or PB
1,000 terabytes or 1015 bytes.
Physical Security
Physical security is the broad term used to define the physical security industry, related to the protection of people, real estate, equipment, resources, etc. Includes a wide portfolio of services including guard services, personal protection, access control, life safety, intrusion detection, video surveillance, etc. Typically does not refer to network or IT security, although closely related.
A pixel is a single point in a standard graphical image. It is the smallest element in an image. Typically, the more pixels or "pix", the higher the quality.
Pixel Resolution
See Pixel.
Pixels Per Inch
Number of pixels in an image for a graphics file or video surveillance camera system. See Resolution.
Power over Ethernet is an electrical transmission standard, that also allows simultaneous data transmission to devices over a standard CAT 5E (Ethernet) twisted pair cabling. Increasingly used for power remote devices such as indoor video surveillance cameras. External video surveillance cameras may have issues with PoE in extreme weather conditions, where the standard does not provide sufficient power for camera, heaters and/or fans for environmental support.
Policy-Based Storage
Policy-based storage enables users to predefine performance and utilization characteristics, and then have the storage device automatically respond with pre-defined actions. Policy-based storage can greatly simplify management tasks for IT and other storage users.
Progressive Scan
A common method for the display, transmission and storage of moving images.
The Physical Security Interoperability Alliance (PSIA) is a global consortium of over 65 physical security manufacturers and systems integrators focused on promoting interoperability of IP-enabled security devices across all segments of the security industry.
Physical Security Information Management (PSIM) systems are a growing segment of physical security, which integrate life safety, access control, video surveillance and other systems into a single management infrastructure.
Acronym for Pan/Tilt/Zoom capability of video surveillance cameras.


See CIF.
176x120 pixel resolution.


Rack unit
See "RU".
Radiology Information System (RIS)
RIS is used by radiology departments to store, manipulate and distribute patient radiological data and imagery. The system generally comprises of patient tracking and scheduling, result reporting and image tracking capabilities.
Known as a Striped Disk Set, RAID 0 provides no data redundancy or protection, but offers best possible speed and performance.
Known as a Mirrored Disk Set, RAID 1 is a storage mirror or mirroring solution. All data is recorded on not just one but two identical drives so that two copies exist at all times. When combined with RAID 0, RAID 1 becomes RAID 0 + 1, commonly known as RAID 10.
Known as a Striped Disk Mirror, with all data mirrored. RAID 10 offers the best of RAID 0 - high performance - with that of RAID 10 - everything is mirrored. For the best performance, RAID 10 is an ideal solution, but it costs more than other implementation since all storage is doubled.
See also "Understanding RAID Systems for Surveillance Storage".
This RAID technology is not used in any commercial storage applications today. It was designed to stripe data to a bunch of drives, with an ECC code symbol stored on a specific drive in the array for data recovery purposes. However, ECC codes are now embedded into disk drives and this requirement has passed.
RAID 3 copies or stripes data across three or more drives at the byte level. One of the drives becomes the parity drive and performs this task. It has been largely replaced today with RAID 5.
RAID 4 is similar to RAID 3 in that it uses stripes across multiple drives, but uses larger stripes for faster read speed. And just like RAID 3, it has been largely replaced by RAID 5.
Known as a Striped Disk Set With Distributed Parity, RAID 5 can survive a single disk drive failure with no loss of data. It is the most commonly used RAID level today and is considered the best all around RAID option balancing price and performance.
Known as a Striped Disk Set With Dual Distributed Parity, RAID 6 deployments can survive a dual disk drive failure with no loss of data. RAID 6 is growing in popularity, since its ability to have two disk drives fail and keep recording is growing in importance as drive capacities - and the time it takes to rebuild them - steadily increases.
RAID Controller
A RAID controller is an intelligent hardware device that is used to provide data protection while controlling and managing one or more storage devices. In video storage, RAID 5 and RAID 6 are the most commonly used.
RAID or Redundant Array of Inexpensive Disks or Redundant Array of Independent Disks
In computing, RAID (or redundant array of inexpensive disks, also later known as redundant array of independent disks) is a system which uses multiple hard drives to share or replicate data among the drives. Depending on the version chosen, the benefit of RAID is one or more of increased data integrity fault-tolerance, throughput or capacity compared to single drives. In its original implementations (in which it was an abbreviation for "redundant array of inexpensive disks"), its key advantage was the ability to combine multiple low-cost devices using older technology into an array that offered greater capacity, reliability, speed, or a combination of these things, than was affordably available in a single device using the newest technology.
At the very simplest level, RAID combines multiple hard drives into a single logical unit. Thus, instead of seeing several different hard drives, the operating system sees only one. RAID is typically used on server computers, and is usually (but not necessarily) implemented with identically-sized disk drives. With decreases in hard drive prices and wider availability of RAID options built into motherboard chipsets, RAID is also being found and offered as an option in more advanced personal computers. This is especially true in computers dedicated to storage-intensive tasks, such as video and audio editing.
The original RAID specification suggested a number of prototype "RAID levels", or combinations of disks. Each had theoretical advantages and disadvantages. Over the years, different implementations of the RAID concept have appeared. Most differ substantially from the original idealized RAID levels, but the numbered names have remained. This can be confusing, since one implementation of RAID 5, for example, can differ substantially from another. RAID 3 and RAID 4 are often confused and even used interchangeably.
Having video storage always available and reliable increases the value of the recorded video, and makes it useful for more applications including physical security and new needs.
Remote Imaging
By employing a remote imaging, remote locations or campuses can be provided with live or pre-recorded television quality broadcasts or static or animated images and video segments of graphical images from various sources.
Resolution is the rate or capacity of a camera, computer graphics, video or other system to measure quality and quantity of images. See Pixel.
Retention is the length of time that video data is recorded and stored for future use. In older tape-based CCTV systems, retention is often measured in days or weeks.
RoHS or the Restriction on Hazardous Substances is a EU director (2002/95/EC), limiting and restricting the use of hazardous substances in electrical and electronic devices including computer equipment and storage for the protection of the environment, and is a component of green IT technology (see "Green IT").
A rack unit, the standard measure of device or system height when mounted in a standard 19 inch wide equipment rack, found in data center, network, video, security and other rack-based environments. Each RU is 1.75 inches or 4.445 centimeters in height.


SAN / Storage Area Network
Storage Area Networks (commonly abbreviated to SAN) are typically used by organizations needing to gain performance, price, scalability and performance improvements over Direct Attached Storage (DAS), such as the storage that is supplied with servers by the server manufacturer, or Network Attached Storage or NAS. Until the advent of IP SAN (or iSCSI SAN), SAN systems were typically based on Fibre Channel (FC) technology. FC is a high performance but complex and costly architecture, with distance limitations that severely restricted the deployment of SAN. With the introduction of IP SAN (or iSCSI SAN), complexity, cost and distance limitations have largely been eliminated.
Serial Attached SCSI or SAS is a computer bus technology primarily designed for the transfer of data to and from computer data storage devices. SAS drives are high performance disk drives, used in some storage vendor products when performance and throughput for databases and other high volume IT needs is desired. SAS drives are beginning to replace more expensive FC drive technology for IT users. When performance is less important than capacity and cost, SATA drives are more commonly used (see "SATA") such as for common video storage needs.
SATA or Serial Advanced Technology Attachment disk drives are next generation technology that replaced Parallel ATA (PATA) drives in storage implementations. PATA itself began as a server-storage oriented replacement for the common IDE technology used in PC disk drives which used parallel signaling. With SATA, a storage system uses a cable to establish a point-to-point connection between devices. SATA and SATA II (with higher data transfer rates) are common in storage solutions today.
Scream sensor
Some surveillance cameras and sensors are equipped with a "scream alarm" or sensor which activates the device based upon a sound or audio range trigger, such as a person's scream or loud noise, useful in public areas such as elevators or doors. Gunshot sensors also fall into this range of devices.
SCSI - Small Computer System Interface, or SCSI, is a common hardware interface first introduced in 1986. Typical SCSI host adapters allow up to 15 or 30 peripheral devices to be connected, and through the SCSI adapter, to the motherboard of the computing device. SCSI technology is found in SANs, server platforms and older technology such as mainframes.
French, "Sequential Couleur a memorie" or in English, Sequential Color With Memory is the analog color television used throughout much of Europe, beginning in France.
Security Industry Association
Security Industry Association (SIA) represents manufacturers, service providers, and distributors of electronic security equipment, and is dedicated to promoting growth, advancement, and professionalism within the security industry. Its activities fall into four core concentrations: government relations, research & technology, education & training, and standards. SIA is an international trade association, formed in 1969, whose membership has grown today to almost 400 companies. Technology, products and services offered by members include, but are not limited to: access control; biometrics; surveillance cameras and systems; fire detection and suppression; home automation; intrusion; remote and wireless monitoring; personal security products and response systems; mobile security; lock hardware; and many specialized services. For information on SIA, go to
Server Appliance
A Server Appliance is a custom-designed platform for physical security applications, video surveillance and industrial video to simplify installation, operation and support. It eliminates the need for commodity servers, which are designed for IT applications like email, word processing and spreadsheets, and not for non-stop, 24x7x365 physical security and/or industrial video usage.
Server/Storage Appliance
A Server/Storage Appliance is a custom-designed platform for physical security applications, video surveillance and industrial video to simplify installation, operation and support. It eliminates the need for commodity servers and storage systems, which are designed for IT applications like email, word processing and spreadsheets, and not for non-stop, 24x7x365 physical security and/or industrial video usage.
See "Security Industry Association".
352x240 pixel resolution.
See CIF.
Acronym for "solid state disk", a storage technology similar to computer memory, without moving parts. Although more expensive and typically available only in smaller capacities than enterprise grade disk drives,prices are decreasing as tiered storage systems begin large scale deployments of SSD technology. SSDs are becoming more common in many applications ranging from IT to physical security.
Standard Definition
Also known as SD, the standard analog definition rate of video surveillance or broadcast television.
Standard Operating Environment
Most corporate and government organizations have standardized on a "standard operating environment". This typically includes industry-standard, current generation computer operating systems rather than proprietary solutions specific to an individual vendor. This enables customers to deploy standard models, support protection tools such as virus protection, and provide transfer of technical skills.
Storage Appliance
A storage appliance is a custom-designed platform for physical security applications, video surveillance and industrial video to simplify installation, operation and support. It eliminates the need for commodity storage, which are designed for IT applications like email, word processing and spreadsheets, and not for non-stop, 24x7x365 physical security and/or industrial video usage.
Storage Array
A storage array provides distinct storage "targets" for one or more client devices, with a high level of data delivery availability. Older FC and newer iSCSI or IP storage arrays are common in IT.
Storage Consolidation
Storage Consolidation - also called storage convergence - is a method of centralizing data storage among multiple servers. The objective is to facilitate data backup and archiving for all subscribers in an enterprise, while minimizing the time required to access and store data. Other desirable features include simplification of the storage infrastructure, centralized and efficient management, optimized resource utilization, and low operating cost.
There are three storage consolidation architectures in common use: network-attached storage (NAS), redundant array of independent disks (RAID), and the storage area network (SAN).
Storage Controller
A storage controller is an intelligent hardware device that is used to control and manage one or more storage devices.
Storage Grid
Storage Grid (also know as Grid Storage) - is a method of linking independent storage nodes that are then monitored by a controlling software layer. It offers easy management, fault tolerance and access at the file and block level. Such an approach is said to reduce down costs, speed up backups and improve utilization.
Storage Networking Industry Association
The Storage Networking Industry Association (SNIA) is a leading industry association in the IT technology industry. The SNIA created the Green Storage Initiative (GSI), dedicated to advancing energy efficiency and conservation in all networked storage technologies and minimizing the environmental impact of data storage operations.
As a vendor-neutral trade organization, SNIA works in conjunction with its members around the globe to make storage networking technologies understandable, simpler to implement, easier to manage, and recognized as a valued asset to business. For more on SNIA, see, see
Storage Snapshot
Storage Snapshot - is a set of reference markers, or pointers, to data stored on a disk drive, on a tape, or in a storage area network (SAN) for IT storage applications. A snapshot is something like a detailed table of contents, but it is treated by the computer as a complete data backup. Snapshots streamline access to stored data and can speed up the process of data recovery. There are two main types of storage snapshot, called the copy-on-write (or low-capacity) snapshot and the split-mirror snapshot. Utilities are available that can automatically generate either type.
A copy-on-write snapshot utility creates a snapshot of changes to stored data every time new data is entered or existing data is updated. This allows rapid recovery of data in case of a disk write error, corrupted file, or program malfunction. However, all previous snapshots must be available if complete archiving or recovery of all the data on a network or storage medium is needed.
A split-mirror snapshot utility references all the data on a set of mirrored drives. Every time the utility is run, a snapshot is created of the entire volume, not only of the new or updated data. This makes it possible to access data offline, and simplifies the process of recovering, duplicating, or archiving all the data on a drive. However, this is a slower process, and it requires more storage space for each snapshot.
Storage Virtualization
See "Virtualization"


Tamper Alarm or Sensor
Some surveillance cameras and other physical devices include a tamper alarm or tamper sensor to detect vandal or other attempts to spoof or disrupt a device.
Total Cost of Ownership, a financial calculation.
Terabyte or TB
1,000 gigabytes or 1012 bytes.
Thin Provisioning
Thin provisioning or TP is a highly advanced software feature that is designed to ensure the maximum utilization and most efficient use of storage space in a modern storage area network (SAN) storage system. Popular in newer IT storage systems, it is typically not applicable in video storage and industrial video today. In IT, not all vendors are able to offer a full thin provisioning system due to the technological requirements, putting them in a distinct disadvantage since they must rely on "fat provisioning" (see "Fat Provisioning").
Tiered Storage
Tiered storage - is the assignment of different categories of data to different types of storage media in order to reduce total storage cost. Categories may be based on levels of protection needed, performance requirements, frequency of use, and other considerations. Since assigning data to particular media may be an ongoing and complex activity, some vendors provide software for automatically managing the process based on a company-defined policy.
As an example of tiered storage, tier 1 data (such as mission-critical, recently accessed, or top secret files) might be stored on expensive and high-quality media such as double-parity RAIDs (redundant arrays of independent disks) using FC or SAS drives, or on Solid State Disk (SSD) devices. Tier 2 data (such as financial, seldom-used, or classified files) might be stored on less expensive media in conventional storage area networks (SANs) using SAS or SATA drives. As the tier number increased, cheaper media could be used. Thus, tier 3 in a 3-tier system might contain event-driven, rarely used, or unclassified files on recordable compact discs (CD-Rs) or tapes.
See VSA Multi-Mode
Two way audio
Some surveillance cameras and sensors provide full duplex or half duplex capabilities to allow capture and transmission of audio signals to and from the device.


See "RU".
A unit of measure. See "RU".


Video Home System or VHS was the most common recording standard, using an analog video cassette first developed by JVC (in competition with Sony Beta or Betamax standard systems) until the early 2000s when surpassed by DVD. Most commercial video is no longer produced on VHS, having moved to DVD. Many video surveillance systems with analog cameras remain available on VHS, but are rapidly giving way in a similar fashion to individual DVRs and, in larger installations, NVRs.
Video Analytics
Typically in a video surveillance system, the "take" is used for real time or near real time applications such as traffic flow monitoring, or for incident recording, such as security or record keeping purposes. In these systems, data is typically retained for no more than 30 days. However, an emerging field of new applications allows for video take to be used for more detailed analysis, security, monitoring, and non-traditional activities that require longer and higher quality, accessible storage of video images.
Video and Data Management & Retention™ Technology
See "VDMR" or click here for more information.
Video Appliance
A general term for a simple device designed to support video applications.
Video Compression
Various standards (JPEG, JPEG2000, MPEG, MJPEG, H.261, H.263, H.264) provide a method of "compressing" or reducing file size for video streams in order to improve performance, throughput or storage capacity.
Video Content Analysis
A subset of video analytics and intelligent video, used for video surveillance applications and often embedded into IP encoders.
Video Management System
A video management system or VMS is a software operation which controls four essential elements of a Video Surveillance application: camera assignment, connection and management; video streaming capture, direction and file recording; retention period management of the recorded file; interface to and distribution of recorded video viewing and analysis.
See also VMS.
Video On Demand / VOD
Video On Demand is a rapidly growing video service that is provided by broadcasters, satellite and cable providers, telecommunications companies, and others to transmit and/or distribute content to individual users.
Video RAID
Video RAID refers to the RAID technology level used to provide protection of video data storage to electronic or digital disk storage. The most common RAID level used today for video surveillance storage is RAID 5.
Video Storage
A storage system designed for video recording and/or playback, as opposed to standard IT storage designed for applications such as email, databases, spreadsheets, etc.
Video Surveillance
Video surveillance is increasingly becoming a digital requirement, where surveillance cameras provide a digital image to a central storage repository for monitoring and control. These systems, originally storing to video tape and later to Direct Attached Storage (DAS) are typically moving to IP SAN (or iSCSI SAN) based systems for inexpensive implementation with reduced complexity and cost.
Video Surveillance Disk Drive or Video Disk Drive
Some PC-grade disk drives have been improved and offered as "video surveillance disk drives" or "video disk drives" for use in PCs, DVRs and NVRs to improve performance and reliability. Many, however, remain based on consumer grade disk drives, and as such often have MTBF ratings of 1 million hours or less.
Enterprise grade disk drives often remain superior (with at least 1.2 million hours MTBF) when the system they are deployed in is designed for non-stop, 24x7x365 video surveillance and physical security needs.
A technique for masking the physical characteristics and complexity of computing and computer storage resources from the way in which other systems, applications, or users interact with those same resources. Virtualization is both a time and resource saver, allowing easier management with fewer managerial and maintenance tasks to perform, as well as a cost saver in terms of standardization, improved uptime, reduced individual systems, and other related benefits. For green IT (see "Green IT"), virtualization allows fewer platforms for less environmental impact.
See also Video Management System.


A data compression format, used in some image compression systems.
Wavelet Transform
Wave transforms are leading edge technology, providing improved video image quality at higher compression ratios than DCT and other compression models. See also "Wavelet".
Wide Dynamic Range
An image stabilization and clarification technology that improves image quality for surveillance camera systems.


X-rays are common medical imaging technology. Using an x-ray beam to create images is one of the earliest and most common of all medical imaging applications.


Zettabyte (ZB)
1,000 exabytes or 1021 bytes.

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