Monday, April 23, 2001		Bits & Bytes

EDFA (Erbium-Doped Fibre Amplifier): It is an optical repeater device that is used to boost the intensity of optical signals being carried through a fibre optic communications system. An optical fibre is doped with the rare earth element erbium so that the glass fibre can absorb light at one frequency and emit light at another frequency. An external semiconductor laser couples light into the fiber at infrared wavelengths of either 980 or 1480 nanometers.

APPC (Advanced Program-to-Program Communications): Also known as LU 6.2 and based on IBM’s SNA, APPC is a communication protocol that transaction programs in a distributed computing environment can use to talk to each other. Using APPC, interconnected systems can communicate and share the processing of programs. It consists of two interfaces: programming and data-exchange.

Data mirroring: The act of copying data from one location to a storage device in real time. Because the data is copied in real time, the information stored from the original location is always an exact copy of the data from the production device. Data mirroring is useful in the speedy recovery of critical data after a disaster. Data mirroring can be implemented locally or offsite at a completely different location.

SIP: Short for single in-line package, a type of housing for electronic components in which the connecting pins protrude from one side. Compare with DIP and PGA. A SIP is also called a Single In-line Pin Package (SIPP).