GlossaryThis glossary defines the special terms,abbreviations, and acronyms that are used in thispublication. If you do not find the term you arelooking for, refer to the index or to the Dictionaryof Computing, 1994.Numbers2:1 compression. The relationship between thequantity of data that can be stored with compression ascompared to the quantity of data that can be storedwithout compression. In 2:1 compression, twice asmuch data can be stored with compression as can bestored without compression.AA. Ampere.ac. Alternating current.access method. A technique for moving data betweenmain storage and input or output devices.accessor. This component contains the library robotand bar code reader. The accessor moves cartridges toand from the I/O Station, storage slots, and tapedrives.adapter card. A circuit board that adds function to acomputer.adj. Adjustment.alphanumeric. Pertaining to a character set thatcontains letters, numerals, and usually other characters,such as punctuation marks.alter. To change.ambient temperature. The temperature of air or othermedia in a designated area, particularly the areasurrounding equipment.ampere (A). A unit of measure for electric current thatis equivalent to a flow of one coulomb per second, orto the current produced by one volt applied across aresistance of one ohm.ANSI. American National Standards Institute.archive. To collect and store files in a designatedplace.ASCII. American National Standard Code forInformation Interchange. A 7 bit coded character set (8bits including parity check) that consists of controlcharacters and graphic characters.assigning a device . The establishing of therelationship of a device to a running task, process, job,or program.assignment. The naming of a specific device toperform a function.asynchronous. Pertaining to two or more processesthat do not depend upon the occurrence of specificevents such as common timing signals.attention (notice). A word for calling attention to thepossibility of danger to a program, device, or system,or to data. Contrast with caution and danger.ATTN. Attention.Bbackup. To make additional copies of documents orsoftware for safekeeping.bar code. A code representing characters by sets ofparallel bars of varying thickness and separation whichare read optically by transverse scanning.bar code label. Paper bearing a bar code and havingan adhesive backing. The bar code label must beaffixed to a tape cartridge to enable the library toidentify the cartridge and its volume serial number.bar code reader. A laser device specialized forscanning and reading bar codes and converting theminto either the ASCII or EBCDIC digital character code.bezel. Decorative and safety cover.bicolored. Having two colors.bit. Either of the digits 0 or 1 when used in the binarynumbering system.BOM or bill of materials. A list of specific types andamounts of direct materials expected to be used toproduce a given job or quantity of output.browser. A client program that initiates requests to aWeb server and displays the information that the serverreturns.buffer . A routine or storage used to compensate for adifference in rate of flow of data or time of occurrenceof events, when transferring data from one device toanother.I-1
