COMPUTER GLOSSARY ----------------- WHAT DOES THAT TERM MEAN? WELL, HERE'S THE ANSWER. Remember all those time you've been reading a computer magazine (be it hard-cover or disk) and the article is about the JT*Q%&N-910563i model T4/%WOTIZTHAT? thingo gadget, and, basically, you haven't got a clue what they are talking about? We've all experienced it at some time. Whether it be when were first introduced to computers (still on our "L" plates"), or a long standing pro, confused by the introduction of a new product. Well, I am going to try and help you out a bit. I might not be able to explain everything, as these are only the basics of computer related terms, so new products probably (definitely) won't be listed. However, I'm pretty sure that a well directed letter or phone call will satisfy your quest for knowledge and give some answers. Most (?) computer stores have at least one person that knows what he (or she) is talking about. If not, they'll have a stab at it. Otherwise, call your local user-group. <<<=== A ===>>> ABORT Stop, don't go any further, hold it! ABSOLUTE ADDRESS A memory address is given from the lowest address in memory, (0000:0000) rather that from somewhere within memory. Compare RELATIVE address. ABSOLUTE CO-ORDINATES Co-ordinates specified relative to a central axis, instead of to the last co-ordinates used. ACCESS TIME Time taken to retrieve or write data, usually to a storage device. eg. disk drive, also RAM. ACKNOWLEDGE An I/O (Input/Output) signal used to say that the hardware has completed its set task, and is ready for another. ACOUSTIC COUPLER A communications device used in serial transmission. Has been replaced in most cases by MODEMs. A/D Analogue to Digital. ADDRESS A location in memory for the storage of data. ADDRESS BUS A major route (set of wires) along which signals travel to indicate a particular ADDRESS. Data can then be taken or put into that ADDRESS by the DATA BUS. AI Artificial Intelligence. This is where a computer is programmed to simulate having intelligence like a human. It is capable of making logical decisions. True AI is some way off. See also NEURAL NETWORKS. AMIGA A REAL computer. Need I say more?! *ANSI Don't know what it stands for! A form of escape code. Mainly used for colours. Such as the codes used in this file to create colour, italics etc. etc. ARCHIVED FILE This actually refers to a file having been stored on tape or disk. Although, now it is used in communications as a time saver. When a file is ARCHIVEd or ARC'ed it is made into a smaller file, or compressed to take up less room, and hence quicker and cheaper to send. ASCII American Standard Code for Information Interchange. An 8-bit information coding system that assigns a number from 0 - 127 for all numbers, letters etc. Also extended ASCII set from 0 - 256 including many symbols. See the inside of the Megadisc10 card for a full list. ASCII TEXT FILE A text file which can be passed form computer to computer because of the standard codes it is made up of. Used for multi-machine access bulletin boards etc. ASPECT RATIO The ratio of vertical pixels to horizontal pixels. ASSEMBLER Software that converts Assembly language source code into machine code. ASSEMBLY LANGUAGE The lowest level programming language, where all of instructions are written to directly control the CPU. ASYNCHRONOUS COMMUNICATIONS A type of data transmission where data can be sent at any time and in a stream. Also called SERIAL communications. <<<=== B ===>>> BACKING STORE or BACKUP Used as a precaution in case a disk crashes etc. We should make backups of all important files, documents and disks. BANDWIDTH Measured in Hertz, is the range of frequencies at which a communications line can transmit at maximum power. BAR CODE A method of easily and quickly reading information. We see similar things in operation at some shopping centres for pricing at cash registers. eg. Franklins. BASIC Beginners All-purpose Symbolic Instruction Code. BATCH FILE A list of DOS commands, used with the EXECUTE Command. eg. the S/Startup-Sequence. BAUD A unit for measuring the number of separate bits or pieces of information that can be transmitted per second. This is usually associated with ASYNCHRONOUS or SERIAL transmission. BCD Binary Coded Decimal. BENCHMARK A standard program that can be used to test the processing power or speed of a computer. BINARY A number system based on 2. only the numbers 0 and 1 are used. BIOS Controls disk drives, keyboard, video display etc. usually kept in ROM, and forms part of the OPERATING SYSTEM (DOS). BIT A binary digit that is the most basic unit of data. Used to create BYTES, NIBBLES, WORDS etc. BIT PATTERN A group of BITs forming a BINARY number eg. an ASCII BIT PATTERN has 7 data BITS and 1 PARITY BIT. BLOCK Usually associated with disks. A collection of WORDS, BYTES or RECORDS treated as one when reading or writing to a device. BLOCK DEVICE A device that sends and receives data in BLOCK units. BOOT To load an operating system. Also concerns the terms COLD BOOT and WARM BOOT. BOOT RECORD This is a short program placed on the disk at the position where the disk is first read when DOS is booted. This then allows the computer to load portions of DOS. On an AMIGA the BOOT RECORD is put in place by the "Install" command. This writes to Sector 0, Cylinder 0, tracks 0 and 1. BPS Bits Per Second (Similar to, but not identical to, BAUD). BUFFER An area of memory used for transferring information from one part of the computer to another. eg. keyboard buffer. BULLETIN BOARD A computer set up for the benefit of others. May be special interest. eg. programming , or general boards where they have an ELECTRONIC MAIL service and PUBLIC DOMAIN software. BUS A circuit for the transfer of data or signals between devices. BUG An error. Be that in HARDWARE, where electrical faults have occurred, or SOFTWARE, where a mistake was made in programming. BYTE A number of BITS (8 in ASCII) used to create a character. Each BYTE represents one character. <<<=== C ===>>> CACHE A BUFFER between the CPU and the memory or a device. This can increase speeds. Some people use disk cacheing for added speed. CAD Computer Aided Design. CAL Computer Assisted Learning. CAM Computer Aided Manufacture. CBL Computer Based Learning. CBT Computer Based Training. CHIP A common name for Integrated Circuit (IC). CHR Abbreviation for CHaRacter CLUSTER A group of disk sectors that form the basic unit in which disk space is allocated. CML Computer Management Learning CMOS Complementary MOS. COBOL Common Business Orientated Language. CODE A series of instructions that make a program. COMAL Common Algorithmic Language A High level programming language. Desended both from basic and pascal COMPILER A program that converts source code, which is usually in a high level language, into machine code, as in the language "C". COPROCESSOR Chips that help speed and assist the CPU. eg. FAT AGNUS, GARY, PAULA, DENISE. CP/M Control Program for Microcomputer (Almost like DOS). CPS Characters Per Second. CPU Central Processing Unit. The "brains" of the computer. In an AMIGA. this is the "Motorola 68000" unless you have some sort of accelerator card installed. CRAY Business founded by Seymour Cray. The designer of many of the most powerful computers in the world. CRITICAL ERROR A DOS interrupt that is invoked when a serious device error occurs. It invokes the DOS "CRITICAL ERROR HANDLER". CRITICAL ERROR HANDLER In the AMIGA's case, this is the Guru handler. This could be replaced with a different handler that informs you of the error, fixes it, then returns operation to the user. (Slight hint to Commodore there!) Software is commercially available to do this (eg. GOMF) but, is not always effective, because the Guru handler can get the error before GOMF does, and hence we see Blink, blink, blink. Guru meditation #000.000000. CR "Carriage Return" - Returns to beginning of line. CR/LF Carriage Return / Line Feed. Moves to the beginning of a new line. CRO Cathode Ray OSCILLOSCOPE. CRT Cathode-Ray Tube. CTS Clear To Send. Used in SERIAL transmission. Gives the O.K for HANDSHAKING to commence.. CURSOR A small (usually rectangular) "box" that appears on the screen to tell you where the text will appear. In some machines, it flashes. CYLINDER In disk drives, the cylinder is the group of tracks at a given distance from the centre of the disk. <<<=== D ===>>> DATA Characters grouped together is a specific pattern to which a meaning is assigned. DCD A signal from a MODEM to the SERIAL port to say that it has made contact with another MODEM. DEBUG Find errors in a program. A long, slow, boring tedious task. DEC Abbreviation for DECimal. DEFAULT For most programs there are default parameters, which means that a window of certain size is opened up, or certain tasks are done, unless the user changes them. DEL DELete - rub-out. DEMODULATOR A device that converts analog signals to digital data. DIGITISER Device that converts analog signals into digits. This can be either music, sounds, or pictures. Digitisers can be for music, or as cameras for pictures. DMA Direct Memory Access. a way of making rapid data transfers between peripherals. DMM Direct Memory Mapping. DOS Disk Operating System. DOWNLOADING Means to take data from a large or, remote computer to a smaller computer, or one in proximity. Take data from that computer and put in onto yours via a data transmission method. eg. MODEM. DOWN TIME the time while a computer is out of service. DP Data Processing. DRAM Dynamic RAM. DSR Data Set Ready. A signal from MODEM to port saying that it is ready to commence. DTP DeskTop Publishing. DTR Data Terminal Ready. A signal from MODEM to say it is ready to receive. DUMB TERMINAL A terminal that can only have input and output. It cannot run programs itself. It acts as a slave to a host. DUPLEX Means data can travel in both directions, but not at the same time. DVORAK One type of keyboard arrangement, less common than the "QWERTY". <<<=== E ===>>> EAROM Electrically Alterable ROM. EDIT The process of changing a file, usually to improve it. EDP Electronic Data Processing. EOF End Of File, in programming and communications. EOT End of Transmission. ELECTRONIC MAIL A system where, messages can be typed, and then left for another on a bulletin board, or transmitted to them, without any need for paper. The message just appears as characters on the screen. ELSI Extra Large Scale Integration. See VLSI. EMULATOR A hardware device (sometime software) that makes the computer believe it was another sort. Therefore, programs written for one sort of computer can be run on another. eg C64 Emulator. EPROM Erasable Programmable ROM (Read Only Memory). ERROR TRAPPING Coding, where upon an error, execution is passed to another part suitable to overcome the error. ESC The ASCII code for Escape. ETB End Transmission Block. ETX End Of Text <<<=== F ===>>> FF Form Feed - Usually means start a complete new page. FILE ATTRIBUTE Setting in a file's directory entry stating the status of the file eg. read, write, archived etc. FIRMWARE Term used to describe programs that are held in ROM CHIPS. FIRST GENERATION COMPUTERS Computers made up of valves, rather than transistors, chips etc. FORTRAN FORmula TRANslation programming environment. FM Frequency Modulation. FS Form Separator. FULL DUPLEX Indicates the transmission of data to and from the computer at the same time <<<=== G ===>>> GIGAFLOP A thousand million floating operations per second. GIGAHERTZ 1000 million HERTZ. GIGO Garbage In - Garbage Out (I encounter this often). GLITCH A BUG caused by a voltage surge or electrical noise that causes an error in data transmission. GS Group Separator <<<=== H ===>>> HACKER A term usually used when refering to software, but also equally applies to hardware. ie. I'm a hardware hacker myself, although I do dabble in a bit of the traditional "hacking". HALF DUPLEX indicates the transmission of data in only one direction at a time. HANDSHAKING Exchanging predetermined signals between two devices to establish a connection between them. HARD COPY Usually used when referring to a copy on paper. ie. via a printer which can be taken away from the computer area. HARDWARE This is all the physical devices of the computer, all the equipment it is made up of. Usually defined as such if it can be picked up and carried away, although this can be a deceptive description. HEX Abbreviation for HEXadecimal. HEXADECIMAL A number system of base 16. Decimal is base 10, meaning it uses 10 digits (ie 0, 1, 2, 3, 4, 5, 6, 7, 8, 9), but HEX uses 16 digits (ie 0, 1, .... 8, 9, A, B, C, D, E, F). HIGH LEVEL LANGUAGE A programming language where each command is used instead of using several machine code instructions. This is usually a simple language to understand and program in. Programs written in a HLL are usually compiled or interpreted languages. eg. BASIC, COBOL, FORTRAN. HRG High Resolution Graphics. HT Horizontal Tab. HYBRID COMPUTER This is a type of computer usually found in Science Labs etc. and are used for transferring the data of interconnected ANALOGUE and DIGITAL devices. HZ Hertz, cycles per second - a measure of frequency. <<<=== I ===>>> IAL International Algebraic Language IAR Instruction Address Register IAS Immediate Access Store IBM International Business Machines (The "Big Blue" - YUK!!!) IC Integrated Circuit ICL International Computers Limited IDP Integrated Data Processing *IEEE A standard interface INITIALIZE The setting up of all values of variables to zero (0) before any execution takes place. INSULATOR A material which has a high resistance to electric current. INTELLIGENT TERMINAL A terminal capable of processing data that is to be carried out without further access to the host. INTERFACE A device that makes the exchange of data between one device and another possible. eg SCSI or IEEE Usually produces codes that are standard to both devices so each knows what the other is doing. I/O Input - Output. The process of transferring data between external devices and the actual computer IRQ Interrupt Request ISO International Organisation for Standardization - a voluntary body formed to provide standards in data communications. <<<=== J ===>>> JARGON Stupid words and ancronyms that computer people make-up to try and confuse other people, like some of the words here. JCL Job Control Language. JOYSTICK Hardware device for providing X-Y input for a computer. Used in the playing of games etc. but has some commercial uses. (Don't tell me you didn't know that one!) <<<=== K ===>>> K Kilo or 1000, but 1024 in computer terms (ie. kilobyte is 1024 bytes ) <<<=== L ===>>> LCD Liquid Crystal Display (like those used in some laptops). LED Light Emitting Diode (Component that allows electricity to flow in only one direction, and emits light. Like the power light in your Amiga). LEO Lyons Electronic Office. (one of the early big computers, 1951). LF Line Feed. Move down one line. LOCATION The place or position in a computer that are able to store data. LOGICAL SECTOR NUMBER A sectors position found by counting all sectors as a sequence starting from the outside edge of the disk, instead of as side x, track x, sector x. LOG IN/ON/OFF/OUT The term used when entering or leaving another computer system. Be that by a terminal in for instance a UNIX environment, of from a bulletin board. LPM Lines Per Minute. LSB Least SIgnificant Bit - or - Least Significant Byte. LSI Large Scale Integration. <<<=== M ===>>> MACHINE LANGUAGE The lowest level of programming, where instructions are written to directly control the CPU. MACRO A pre-defined set of instructions used as a "shortcut" MAP Microprocessor Application Project. MEGABYTE A million BYTEs. MEGAFLOP A million floating operations per second. MICR Magnetic Ink Character Recognition (not used very often now). MIDI Musical Instrument Digital Interface. MIPS Millions of Instructions Per Second (used instead of MEGAHERTZ for VERY fast computers). MODEM MOdulator - DEModulator. MPU MicroProcessor Unit. MSB Most Significant Bit - or - Most Significant Byte. MSI Medium Scale Integration. MULTIPLEXOR Hardware device where many similar devices (eg. terminals) can be used by one device along the same wires by switching attention between them. <<<=== N ===>>> NAK Negative Acknowledgement in communications. NIBBLE Half a BYTE, or 4 BITs. NOISE The cause of some errors transmitted via phone or cable. Due to frequency interference and electromagnetic radiation produced by other electrical things. eg. printer. NUL abbreviation for NULL, or nothing. <<<=== O ===>>> OCR Optical Character Recognition (More like our modern Scanners). OCTAL COunting system of base 8. OEM Original Equipment Manufacturer (and usually places a copyright on the product/equipment). ON/OFF LINE Being connected and operable or not. eg. printer. OPTICAL DISK Like a Compact Disc (C.D). Has very large storage capacities up and above for example 600 megabyte. That's a lot more than out standard 3 and a half inch disks. Modern technology has made it possible for these to be read and written. They have progressed beyond WORM technology. OSCILLOSCOPE An electronic instrument for showing wave forms. <<<=== P ===>>> PAL Phase Alternation Line (a type of TV signal/system). PARALLEL TRANSMISSION A method of sending data between devices simultaneously through separate wires (side by side). This is much faster than ASYNCHRONOUS or SERIAL transmission. PARITY BIT An extra BIT that is added to ensure that there are no transmission errors. Set to either odd or even. When data is received, if it not the correct value (odd or even), a request is made to re-send the data. PARTITION Method of setting up a hard disk so as it can be referred to as many different physical devices. PASCAL High Level Programming Language. PASSWORD A group of characters that must be given to the user to allow access. PCB Printed Circuit Board. PEL Same as PIXEL, ie, Picture Element. PERIPHERAL A device that can be connected the computer and controlled by the CPU. PHYSICAL CO-ORDINATES The co-ordinates of a point as referred to from the top corner as (0,0). PIXEL PICture ELements. PILOT A programming language. PIO Programmable Input - Output. PRINTER Peripheral used to get output or hard-copy from the computer eg. dot-matrix, daisy-wheel, laser, ink-jet. PROM Programmable ROM. PROMPT A symbol to show the beginning of a command line, as in the CLI Sometimes referred to as the CURSOR. PROTOCOL The system of parameters and data formats used by a device. eg. ZMODEM PUBLIC DOMAIN Software released by people, often of very high quality, to the AMIGA community for no apparent reason at all. (?) Some charge a small fee if you wish to use the product, but, the software is otherwise free of charge. <<<=== Q ===>>> QWERTY One type of keyboard (look at yours - top left of letters) It is possible to type at reasonable speeds with the QWERTY keyboard. I type at about 40 WPM. Yet, the QWERTY keyboard was designed to slow typing speeds, because of the mechanical nature of early typewriters. See DVORAK. <<<=== R ===>>> RAM Random Access Memory. RELATIVE ADDRESS A memory address that is described as an offset from some point defined in memory. RELATIVE CO-ORDINATE A co-ordinate that is fixed relative to the last co-ordinate used. RESERVED WORD Word that cannot be used by the programmer because they are commands eg. a BASIC programmer cannot use words like TAN, SIN, SCREEN, WINDOW in their variables or labels because they are words used by the language. RESPONSE TIME Time taken for action to be taken upon a command, either to access a disk, memory, print the entered data etc. REQUESTOR In an AMIGA, this is the window that pops up, asks you a question, giving you 2 or more options to choose by clicking in the appropriate box. eg. ______________________________ | Please insert volume | | NTA 40 | | in any drive | | _________ __________ | | |___OK___| |_Cancel_| | |____________________________| RF Radio Frequency. RI Ring Indicator. RIGHT JUSTIFICATION Usually used in word Processing. Means that all the text is set to line up on the right hand side eg. my introduction was right justified to 73, but all this lower portion is not right justified. RISC Reduced Instruction Set Computer (the latest trend). RGB Red, Green, Blue. ROM Read Only Memory (This term is wrong really. Because it's not always read only. You can write to some ROMs). ROOT DIRECTORY The central directory on a disk. It contains a volume label, pointers to subdirectories, and always occurs at a fixed place. RS Record Separator. RS232 A standard serial interface (We have one on our Amiga's) Usually consists of a DB25-pin socket, with each pin assigned a different task and function. RS423 Another standard serial interface (MACs use this ???). RTL Resistor Transistor Logic. RTS Request To Send. <<<=== S ===>>> SECTOR A portion of a track which usually holds about 512 bytes of data. SECOND GENERATION COMPUTERS Computers made up of transistors SEGMENT An area of memory set up to hold code, data, or stack. SEEK TIME Time taken to position the head over a specific CYLINDER or TRACK on a disk. SERIAL COMMUNICATIONS The same as ASYNCHRONOUS COMMUNICATIONS. SCSI Small Computer Systems Interface. (Pronounced "skuzzy") An interface that was decided upon as a standard by ISO. SIMPLEX The transmission of data in one direction only. SO Shift Out. SOURCE CODE A program as it is originally written, before compilation, assembly or interpretation.. SSI Small Scale Integration. ST Standard Technology (ATARI) ha! ha! ha! STACK An area in memory where the program temporarily holds data. STACK SEGMENT An area set of memory set aside by a program to hold the stack. START BIT Used in SERIAL communications. A START BIT is sent before every WORD that is sent STOP BIT Used in SERIAL communications. A STOP BIT is sent after every WORD that is sent, so the line is kept in a waiting state. STREAMING TAPE Method of storage used in UNIX type systems. Also often used as BACKING-STORE for other DOS systems. STX Start of Text. SUB Substitute. SYN SYNchronous idle. SYNTAX The rules governing the structure of a command or a programming language. SYSOP SYStem OPerator, of a Bulletin Board Service (BBS), for example. <<<=== T ===>>> TELECOMMUNICATIONS The sending of data via radio waves or cables. TERAFLOP A million million floating operations per second. TERMINAL A device connected to a computer that allows input and output of data consisting (normally) of a keyboard and VDU. THIRD GENERATION COMPUTERS These were built after about 1966 as they were made up of IC's. TIME SHARING Method used where 2 or more users can use the same computer (host) at the same time. Similar to multi-user in concept. TRACK A ring of disk space, which are divided radially into SECTORS. TREE STRUCTURED DIRECTORY A system of sub-directories organized like the branches of a tree. TRL Transistor Resistor Logic. TSR Terminate and Stay Ready. TTL Transistor Transistor Logic. <<<=== U ===>>> UART Universal Asynchronous Receiver / Transmitter. This device can convert SERIAL to PARALLEL digital data, and vice versa ready for transmission or receipt by a MODEM. UHF Ultra High Frequency ULA Uncommitted Logic Array (dunno' what it means!). UNIVAC Universal Automatic Computer (Another early computer, 1951). US Unit Separator. USER GROUP A group of people who have common interests in computers who meet regularly, discuss different topics, some provide services like software sale, electronic mail, distribution of PUBLIC DOMAIN etc. <<<=== V ===>>> VDU Visual Display Unit (Your looking at one) eg. Monitor or TV. VHF Very High Frequency. VLF Very Low Frequency. VLSI Very Large Scale Integration. VOLATILE MEMORY Refers to all types of memory that are wiped when power is cut eg. RAM. VOLUME LABEL A special directory entry to provide an identifier for disks. VT Vertical Tab <<<=== W ===>>> WAFER A very thin slice cut from a crystal (eg. Silicon) and led to the formation of the IC. WAIT STATE A time during the execution of a program when execution is interrupted for an I/O operation. WINCHESTER A company that was one of the first to come up with hard disk technology. Capable of storing much more than the standard disk in the same space. WORD Refers to the size of a basic data unit. WORK STATION Similar to a TERMINAL. WORLD CO-ORDINATES Much the same as PHYSICAL CO-ORDINATES. WORM Write Once - Read Many Also a trojan horse type program that can be inserted in front of others, capable of wreaking havoc. WP Word Processor (we've all got at least one of these). <<<=== X ===>>> XON/XOR A HANDSHAKING method used in asynchronous communications. XMODEM One method of handshaking used in communications. X-Y Referred to when using two directions at right angles <<<=== Y ===>>> YMODEM Another method of handshaking <<<=== Z ===>>> ZMODEM Another method of handshaking I think I have nearly all the basic terms you will come across. I've probably missed some of the most basic terms , but, oh well. Add to the list yourself as you wish. I've provided the basics, you extend on it. It might be worthwhile to save this as an ASCII file to RAM: and then archive this file on your Word Processing disc so as you can easily access it to read, or add to. May also be worthwhile making a hard-copy (ie. printing out) so you can quickly refer to it. You've got it now, so do what you like with it. Paul Moxey Many thanks go "COLLINS GEM", "YOUR COMPUTER" and a few friends for the help that they gave in defining some of the tricky ones.