The Digital Fact Book - Quantel

However, in practice it can be difficult to sustain multiple high bandwidth (e.g. 2K or 4K)streams from a SAN. Quantel’s Genetic Engineering is a recent development designed tosolve this problem and is capable of playing back multiple 2K and 4K streams simultaneously.See also: FAN, Fibre Channel, NASWebsite: www.snia.orgwww.techweb.com/encyclopedia/defineterm?term=SANSATASerial ATA (Advanced Technology Attachment) is designed to transfer data between disksdrives (hard and optical) and computer hardware and is the successor of ATA. SATA adaptersand devices communicate over a high-speed serial link originally specified in SATA I at 1.5Gb/s, now SATA II at 3 Gb/s and SATA III at 6 Gb/s is planned. The serial interface meansthe connector is smaller (than ATA) and can run faster – as fast parallel data starts to sufferfrom skewing – serial does not. SATA does not just serialize ATA. SATA II adds native commandqueuing, originally a feature of SCSI, that allows handling multiple pending transactions ratherthan just one at a time. This allows the disk to organize the transactions for faster operation.Website: www.sata-io.orgSScalingAnalog video signals have to be scaled prior to digitizing in an ADC so that the full amplitudeof the signal makes best use of the available levels, or numbers, in the digital system.The ITU-R BT.601 digital coding standard specifies, when using 10 bits, black to be setat level 64 and white at 940. The same range of values is ascribed should RGB be used.Computer applications tend to operate with a different scaling with black set to level 0and white at 1023. For color they usually use RGB from 0-1023. However, most still keepto 8-bit accuracy so the scale runs from 0-255. Clearly, going between computers and TVrequires processing to change color space and scaling.See also: Into digits (Tutorial 1)SchemaA collection of tables and constraints that describe the structure of a database. It providesa level of security as no one else can interpret the stored database without the schema;it is just a collection of figures. It organizes the database to allow scalability for expansionand defines efficient operation to suit a particular application.Scrub (audio)Replay of audio tracks at a speed and pitch corresponding to jog speed – as heardwith analog audio tape ‘scrubbing’ backwards and forwards past an audio replay head.This feature, which is natural for analog fixed-head recorders, may be provided on a digitalsystem recording on disks to help set up cues.150