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When Is A Computer?

an A to Z of micro talk


An A to Z of computer jargon made sensible by Andy Honeybone. Now you, too, can understand what shop assistants really mean when they're after your wallet.

Roll your own jargon with this glib glossary brought to you by Dr Spliff Hair Products Inc. Test your friend, bore your friend, spout endless 'did you knows', or have a cup of tea but, first of all, start here.



ADC Analogue to Digital Converter. Front end hardware of a sampling system (Emulator, digital echo/delay, digital recording). Not to be confused with Aide-de-Camp.

ADDRESS A memory location.

ALGORITHM A description of a method or process used to solve or create your desired end.

ALIAS Distortion arising from attempting to sample a frequency component higher than twice the sampling rate.

ALPHANUMERIC Comprising letters and numbers.

ANALOGUE Continuously variable quantities like the voltage output from a microphone or guitar pickup.

ASCII American Standard Code for Information Interchange. A widely used communications code (49 = 1, 65 = A, etc).

ASSEMBLER A program which converts a sequence of (almost) intelligible microprocessor instruction mnemonics into raw "ones" and "zeros" for digestion by the computer.



BAR CODE Data transfer using the widths and separation of printed vertical lines.

BACKING STORE Some form of non-volatile storage for programs and data-audio cassette, floppy or Winchester discs.

BASIC Beginners' All-Purpose Symbolic Instruction Code.

BAUD A measure of the rate of serial communication in bits per second. The MIDI standard specifies 31.25kBaud.

BINARY A number system using only the digits "one" and "zero". As these correspond to electrical on and off states, it is the basis of all computer workings.

BIT The smallest divisible part of a computer word. A solitary "one" or "nought".

BOOT To start a computer up from 'cold' – usually by loading the operating system.

BUFFER Memory reserved for temporary data storage.

BUG An error – possibly arising from a sequence of events not envisaged by the programmer. A balls up (colloquial).

BYTE A computer word, eight bits long.



CARRIER (FM) The sine tone (operator) which is to be modified.

CMOS A semi-conductor production process giving very low power devices suitable for battery-backed memory. Complementary Metal Oxide Semi-conductor.

COMPANDING A non-linear technique used to squeeze a greater dynamic range from DACs and ADCs than would be possible with standard devices.

CPU Central Processing Unit. The microprocessor and its support chips.

COMPARATOR An analogue circuit which switches when one input exceeds a reference at another. It is an integral part of an ADC.

CONVERSION TIME The time taken to convert from analogue to digital or vice versa. Can limit the sample rate.

CREATE File creation is the process of giving a name to a file and updating various directories.

CURTIS A manufacturer of analogue synthesiser integrated circuits which are widely used in Sequential Circuits and Oberheim instruments.

CUSTOM Integrated circuits made to a customer's specification and not available commercially.



DAC Digital to Analogue Converter. Hardware at the output of Compact Disc players, digital instruments and digital delays.

DATA Pitch, duration, number of voices, etc. Values for a computer program to work on.

DCB Digital Control Bus. A Roland pre-MIDI interface.

DEFAULT A value assumed if not directly specified, usually the most common value. A music composition language which had a default note duration of a crochet would save much typing.

DIGITAL FILTER A software equivalent of an analogue filter circuit. Very predictable responses with sharp roll offs can be achieved by this technique.

DITHER is noise added to a signal during sampling which ironically has the effect of improving sound quality by randomly pushing fine detail into the conversion.

DMA Direct Memory Access. A technique which allows fast data transfer from computer memory to a peripheral without that data passing through the CPU.

DOMAIN An entity or quantity which has a world of its own – frequency, time, analogue, digital, etc.

DONGLE An anti-pirating device for software. The dongle is a small piece of hardware positioned outside the computer without which the associated software won't work.

DOS Disc Operating System. Software which enables files to be opened, closed, deleted, renamed, copied, etc in response to commands from the keyboard. A fundamental housekeeping package which provides an environment for further software. Examples CF/M, MS-DOS, UNIX.

DSP Digital Sound Processing. Mixing desk effects performed within a computer.

DUMP To send a chunk of memory to an external device. The chunk may contain a program or voice/sequence data.



EEPROM Electrically Eraseable Programmable Read Only Memory (E squared PROM). A newly developed form of non-volatile storage which does not require battery back-up and can be reprogrammed without removal. It is finding use in voice storage memory packs.

EXTENSION An additional qualifying part of a filename, usually separated from the main identifier by a dot. In Fairlight terminology a file named BONG could have extensions .VC for a voice file, .CO for a control file or .SQ for sequence data.



FILE An electronic data dossier usually stored on magnetic media.

FIRMWARE Software 'blown' into Read Only Memory (ROM).

FLOPPY A magnetic oxide coated disc which spins inside a protective jacket. Used for data/program storage. Do not bend, store in magnetic fields, touch the exposed surface or spread with jam.

FM Frequency Modulation. A synthesis method which can produce complex waveforms by the modulating action of a modifier on a carrier.

FOURIER A synthesis method which produces complex waveforms by adding harmonically related sine waves in various amplitudes and phases. The Discrete Fourier Transform is a mathematical procedure to convert these components into a set of samples (wave-table) and vice versa.

FUNDAMENTAL The reference frequency for a harmonic series.



GLITCH An electronic spike or discontinuity.



HANDSHAKE A method of making sure that a peripheral is only sent data at a pace it can keep up with.

HARDWARE Tangible lumps of metal and circuitry.

HARMONIC A frequency which is a whole number multiple of a lower tone (the fundamental).

HEXADECIMAL A number system using the characters 0 to F to represent values 0 to 15. The "ones" and "noughts" of binary are split into groups of four (1111 = 15) and each group can then be assigned one of the hex characters (0101 1110 = 5E).

HOST The computer running the software.



ICON A graphic symbol representing an action – a filing cabinet for file manipulation, a dustbin for discarding etc.

INTERFACE A standard connection and software protocol to present or extract computer signals.

INTERRUPT A computer feature which allows an instant response to a realtime event, even though the computer may be 'busy' doing things other than waiting for that event.

I/O Input/Output. Connections to and from the micro which are a requirement for interfacing and expansion.



K Abbreviation of kilo meaning a thousand or in computer-speak, 1024. 8k of memory is actually 8192 bytes.



LATCH A memory cell used to store transient data.

LCD Liquid Crystal Display. A very low power display technology which does not give off light but changes from translucent to opaque. Restricted viewing angle.

LED Light Emitting Diode. A power thirsty display technology which is becoming increasingly powerful and rugged.

LIGHTPEN A photo-receiver mounted in a pen barrel which when touched against a screen can send a signal to the micro to allow its position to be calculated. Used to draw waveforms and save typing.

LOGICAL Existing in software only – not actual. As in 16 logical oscillators.

LOW-PASS The characteristic of a filter needed to prevent aliasing by removing signal frequency components higher than half the sampling frequency.

LSB Least Significant Bit. The bit of a digital word which affects the value least when changed from 0 to 1.



MAPPING Programming a computer to cross some wires. For example, making the snare sound come from the bass drum pad.

MCL Music Composition Language. A program to turn technicians into musicians and musicians into typists.

MENU A list of options. Each option may be another menu. A means of rapidly locating one program function.

MICROPROCESSOR Cheap ones are made of plastic and have plain pins but expensive ones are ceramic and have gold plated pins.

MIDI Musical Instrument Digital Interface. A can of worms.

MNEMONIC A shortened form or memorising aid.

MODIFIER Yamaha FM synthesis terminology for a modulating oscillator.

MODULATION INDEX (FM) The ratio of the spread of the harmonic spectrum (deviation) of the carrier to the frequency of the modifier. A gauge of modulation depth.

MONITOR (a) A bare bones program which allows programs to be loaded and run. (b) A cathode ray tube visual display unit.

MOUSE Functions like a joystick but is a roughly rodent sized case which can be easily moved around on a table. Sensors inside the mouse detect the motion and feed the information into a computer where it may be used to control the cursor. The socket for connecting a mouse is known as the 'mouse hole'.

MSB Most Significant Bit. The bit of a binary word which is 'worth' the most. The pounds rather than pence.

MSX A breakthrough in standardisation allowing transfer of programs and peripherals between different makes of computer. The language is Microsoft extended Basic.

MULTIPLEX MUX-sending many signals down one wire and separating them at the far end. FM stereo radio left and right channels are transmitted in a multiplexed form.



NIBBLE Half a byte-four bits.

NMOS A fabrication process used for the majority of microprocessors and their support chips.

NON-VOLATILE The property of a memory to remember its contents when the main power supply is removed. Battery back-up systems can support CMOS memory and ROMs retain their information even if removed from the circuit board.

NYQUIST Theorist who stated that signals of frequencies up to almost half the sampling rate can be handled by ADC and DACs without distortion.



OPERATOR (FM) Yamaha terminology for a logical oscillator. Both carriers and modifiers are operators.

OPTO-COUPLER An isolating device that talks between its two independent halves by pulsing a light. MIDI communications utilise these devices to prevent hum loops.



PAGE (a) One of a selection of menus (b) A chunk of memory (ie zero page is 256 bytes often advantageously used for variable storage in 6502 processor systems like the BBC).

PARALLEL A multiwire interface which is often less complicated and faster than a serial system.

PARAMETER General term for a facet of a sound which can be controlled. For example pitch, waveform, attack, etc.

PCM Pulse Code Modulation. A sampling system which assigns pulse codes (patterns) to input values falling between quantisation levels. Morse code is a well known example of a pulse code.

PERIPHERAL Something connected but outside the main housing of the computer such as a printer or disc drive.

PROM Programmable Read Only Memory. A device which starts off in life a 'one' in every location and ends up riddled with noughts as a programming device vaporises internal metal links to give the desired word patterns. No further change is then possible.

PROMPT A hyphen, question mark, underscore or graphic character, possibly flashing, which appears on a VDU to coax the operator to type a command at the keyboard.

PROTOCOL An established procedure. In a MIDI transmission, the protocol is one start bit, eight data bits and then one stop bit.



QUANTISATION Cutting out the in betweens – converting to steps that can be represented by digital numbers.

QWERTY The first six alphabetic characters of a standard typewriter style keyboard. Boring people say the order resulted from the mechanical arrangement necessary to stop often used consecutive letters from jamming but I prefer the story that the first row of keys contain all the letters for the word TYPEWRITER so that salesmen of yore could easily demonstrate the machine. Try it.



RAM Random Access Memory. The type of memory used for holding values which the computer must be able to change. Sometimes called Read/Write memory.

REAL-TIME As opposed to pretend-time, it refers to a computer system which reacts instantly to inputs rather than getting round to it when it is ready.

REFRESH 'Normal' memory is referred to as static because the data is held by transistor switches which stay put. Dynamic memory is the alternative which, because it stores its data on capacitors which leak, has to be refreshed (reminded) at intervals.

REGISTER A byte, possibly within a microprocessor, with specific functions.

RETROFIT To add additional features to a machine previously sold without. For example a MIDI interface. To up-grade.

RIBBON A thin cable of bonded parallel conductors. Often used to link circuit boards.

ROM Read Only Memory. Non-volatile software carriers (firmware) whose content is decided at manufacture.

RS232/423 Serial communications standards.



SAMPLE An instantaneous measurement of the amplitude of a signal.

SAMPLE AND HOLD Hardware used to freeze a signal prior to its conversion to digital.

SCREEN Used by the language FORTH to mean a 1k block of program text.

SERIAL Data transfer down one wire. Bit by bit, one after another.

SIDEBAND (FM) Name given to frequencies formed higher and lower than the carrier as a result of frequency modulation.

SINE The mathematical function which describes a waveform which has no harmonics.

SOFTWARE Items washed in fabric conditioner.

SSM Solid State Music. A manufacturer of the analogue synthesiser chips used in early Prophet-5 models.

START/STOP BIT In serial communications (MIDI) the start bit is transmitted to tell the receiving UART that 8 data bits are following. The stop bit completes the frame.

STATIC (a) Memory which does not have to be refreshed. (b) High voltage, low current electricity which can destroy micro-electronic circuitry.

STATUS Posh word for 'is it working?'.

STEP-TIME A term used in sequencing to mean no rhythmic variation is possible unless edited later.

STRING A row of characters of no pre-determined length.

SUCCESSIVE APPROXIMATION An analogue to digital technique where starting with the MSB, each bit of the DAC is switched on in turn and a comparison made with the value for conversion. If the approximation is too large, that bit is turned off and so the resulting bit pattern is the binary value of the input voltage.

SYSTEM DISC The disc which holds the operating system and is the entrance to all other programs.



TTL Transistor Transistor Logic. A family of integrated circuits which are widely used for simple functions within microcomputers.

TWISTED PAIR MIDI connection cable specifies a screened twisted pair and this is just what it says – two wires twisted together. This gives better protection from mains pick-up than normal braided screening.



UART Universal Asynchronous Receiver/Transmitter. A serial communications byte slicer.



VDU Visual Display Unit. A TV type screen which produces backache, eye strain and does unmentionable things to unborn children.

VLSI Very Large Scale Integration. Putting lots of transistors on one chip.



WAVETABLE A chunk of memory which holds numbers representing the profile of a waveform cycle.

WINCHESTER A superfloppy disc not removable from its drive but holds about 20 megabytes.


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Cutec MX 1210 Desk

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One Two Testing - Copyright: IPC Magazines Ltd, Northern & Shell Ltd.

 

One Two Testing - Aug 1984

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Computing


Feature by Andy Honeybone

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