EDIT2 - a case story

Glossary

This glossary contains an explanation for some of the technical terms which are used on this website - be aware that some of these terms may have other meanings when used in another context.

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Analogue	Traditional methods of electrical signals to represent, usually infinitely variable between a zero reference and a defined peak level, to represent actual signals received, recorded or generated by an electrical device such as a cathode ray tube, microphone or grammophone stylus. Given high quality sensing devices and processing electronics, analogue signals will be more discreet and authentic than their digital equivalent, in that analogue signals are stepless. Multigeneration copying of analogue signals gradually increases the noise component inherent in the pick-up device, processing system and recording medium, which eventually degrades the signal integrity. In many creative processes, analogue methods are preferred as they preserve signal components which - albiet invisible/inaudible to the audience - produce perceptable harmonics which contribute to the authenticity of the result. To save processing power and storage space, many digital processing and recording techniques reduce the storage of such signal components.
ATR	Audio Tape Recorder - this may be digital or analogue

B
Bandwidth	The measure of speed/capacity of a given electronic or data systems ability to handle signals or data. Bandwidth can be increased by designing the system to handle the throughput of more data (usually expressed in Mbits/sec). Faster processors, faster network transmission nethods, data compression, increased bit-handling and data caching all contrinute to greater bandwidth. In the analogue television world, bandwidth is also used to express the ability of an electronic circuit, device or system to handle a given range of frequencies. The greater the bandwidth of a videotape recorder, the greater its ability to resolve the high frequency signal components. To allow for the natural harmonics of a multi-frequency signal, the rule of thumb is that the circuit, device or system must have twice the bandwidth of the highest frequency in the application.

C
Clone	The term was originally coined in the 80's, when Far-East manufacturers began to copy IBM's AT standard components - resulting in IBM adopting a closed architechture - the microchannel bus - which within a few years won IBM the distinction of being the meant that the only manufacturer not selling "IBM compatible" products! A clone is a "no-name" (often milky cream plastic covered) computer product or component, typically though not exclusively originating from the far-east market, the manufacturer of which is usually unidentifiable to the end-user, and which often lacks documentation. Clone products vary in quality - the term includes both excellent motherboards and cheap inferior keyboards. Clone products are maybe the closest the computer industry comes to a common standard - although the clone standard is usually dictated by the lowest common denominator. Clone products are not inherently sub-standard - it depends on the application and the level of reliability desired. Clone products are also characterised by the difficulty of buying the same component a few weeks later - so where matched components are required, clones may be unsuitable. For non-critical applications, clone products may be the best value for money. For critical applications, they can be a nightmare! Clone motherboards have been useful in the broadcast television industry because they generally have allowed the user a high level of control over IRQ resource allocation. With the advent of Windows 2000 and WHQL tested components, such control has become impossible.

D
Digital	In digital encoding, processing and recording the signal is a built up in discreet values rather than stepless values - for instance, the amplitude of a signal - for example the red, green or blue component of a television signal or digital image - may be determined as one of a fixed number of numeric values between 0 and 255 - all values in the original source, which do not directly equate to a specific digital value, would be rounded up or down to the nearest whole number. Given corrct encoding, an uncompressed digital signal will retain exactly the same values when it is copied. The widespread use of compression - often several forms of compression one after the other - will gradually degrade the original digital data, as each level of compression effectively erases some of the original data from which the image or signal must be reconstructed. The objective with all compression and multi-generation digital processing is to maintain such degradation below the level perceiveable by the person who will ultimately receive, see or hear the signal. As consumer video, audio and television equipement improves, the threshold for what is ultimately perceiveable drops, and digital artefacts which previously would have been hidden in an analogue transmission process become visible. Professional photographers, graphic artists, sound engineers and musicians rarely agree on what is perceivable or not, hench many musicians preferrence for high-fidelity analogue recording methods.


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Linear	Recording and eding processes in which the recorded data (which can be either analogue or digital) is recorded in chronological order on a medium (usually tape). The greatest limitation of linear technology is that any modificatiuons to that part of the programme which has already been edited, can only be accomplished either by replacing the sequence with a new sequence of identical duration, or erasing the medium from the point at which the modification begins, and re-editing the rest of the programme. (see also non-linear and NLE)

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N
Non linear	non linear editing allows access, modification and processing of all programme data, irrespective of its chronological position in the programme timeline. Non linear digital diting allows the same level of flexibility as traditional film editing, in which the film can be cut and spliced at will. NLE is the common abbreviation for the technology in television and film applications.
NLE	(see non linear)

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P
Precision	Workstation series of products manufactured by Dell. EDIT2 is based on the Precision 530 Workstation
Power vault	Storage products manufactured by Dell. EDIT2 uses ther 200 series
Power edge	Server products manufactured by Dell. EDIT2 uses a Power Edge 6400 chassis for the 530 workstation
PERC2	Power Edge Raid Controller - a Dell generic name for a series of intelligent RAID controllers manufactured by leading third-party manufacturers such as AMI or Adaptec. The PERC2 is a U80 SCSI device, which can be fitted with up to 128MB cache and battery-backup. Models with /DC suffix are dual channel. Models with /QC suffix are quad channel. EDIT2 has used the AMI version of this product.
PERC3	Power Edge Raid Controller - a Dell generic name for a series of intelligent RAID controllers manufactured by leading third-party manufacturers such as AMI or Adaptec. The PERC3 is a U160 SCSI device, which can be fitted with up to 128MB cache and battery-backup. Models with /DC suffix are dual channel. Models with /QC suffix are quad channel. EDIT2 now uses the AMI version of this product.

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Redundancy	The degree to which a system, or components in a system, may be be removed or fail, without the entire system or sub-system being out of operation. In relation to RAID storage, redundancy is the percentage of drive capacity which must be discounted when calculating total available capacity, to take account of the, often unseen, space required for storing the data which is necessary for restoring a lost drive. Redundancy is also allowed for in terms of drive or RAID performance, as some drives/RAIDs do not perform well if they are filled completely with data. Redundancy calculations for storage are seldom completely accurate, and rely on a degree of judgement depending on the application and system configuration (see media storage issues)

S
silver.	A digital MPEG2 based non-linear video/audio editing system manufactured by FAST multimedia AG

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VTR	Video Tape Recorder - can be analogue or digital. The abbreviation VTR is also used for cassette based video recorders, which - especially in the US - are also known as VCR's. A VTR can be a deck which only allows playback (not recording). Broadcast editing VTR's have complicated servo circuitry which enables precise timing of one VTR in relation to another.
VCR	Video Cassette Recorder - can be digital or analogue. The abbreviation VCR is used primarily for consumer video recorders such as VHS and Betamax.

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