@DATABASE Hardware Manual
@NODE MAIN "Amiga Hardware Reference Manual: Glossary"
@INDEX Hard_Index/MAIN
@TOC Hardware_Manual/MAIN
A                                         I
@{ " address " link gloss-1}                                 @{ " interlace mode " link gloss-77}
@{ " Agnus " link gloss-2}                                   @{ " interrupt " link gloss-78}
@{ " aliasing distortion " link gloss-3}                     J
@{ " Alt keys " link gloss-4}                                @{ " joystick " link gloss-79}
@{ " Amiga keys " link gloss-5}                              L
@{ " AmigaDOS " link gloss-6}                                @{ " light pen " link gloss-80}
@{ " amplitude " link gloss-7}                               @{ " local bus " link gloss-81}
@{ " amplitude modulation " link gloss-8}                    @{ " longword " link gloss-82}
@{ " arbitration " link gloss-9}                             @{ " low " link gloss-83}
@{ " asserted " link gloss-10}                                @{ " low resolution (Lores) " link gloss-84}
@{ " atomic cycle " link gloss-11}                            M
@{ " attach mode " link gloss-12}                             @{ " manual mode " link gloss-85}
@{ " AUTOCONFIG(TM) " link gloss-13}                          @{ " master " link gloss-86}
@{ " automatic mode " link gloss-14}                          @{ " MIDI " link gloss-87}
B                                         @{ " microsecond (us) " link gloss-88}
@{ " backplane " link gloss-15}                               @{ " millisecond (ms) " link gloss-89}
@{ " barrel shifter " link gloss-16}                          @{ " minterm " link gloss-90}
@{ " baud rate " link gloss-17}                               @{ " modulo " link gloss-91}
@{ " beam counters " link gloss-18}                           @{ " motherboard " link gloss-92}
@{ " bitmap " link gloss-19}                                  @{ " mouse " link gloss-93}
@{ " bitplane " link gloss-20}                                @{ " multitasking " link gloss-94}
@{ " bitplane animation " link gloss-21}                      N
@{ " blanking interval " link gloss-22}                       @{ " nanosecond (ns) " link gloss-95}
@{ " blitter " link gloss-23}                                 @{ " negated " link gloss-96}
@{ " burst " link gloss-24}                                   @{ " non-interlaced mode " link gloss-97}
@{ " bus cycle " link gloss-25}                               @{ " NTSC " link gloss-98}
@{ " bus hogging " link gloss-26}                             @{ " nybble " link gloss-99}
@{ " bus starvation " link gloss-27}                          O
@{ " byte " link gloss-28}                                    @{ " overscan area " link gloss-100}
C                                         P
@{ " Chip RAM " link gloss-29}                                @{ " paddle controller " link gloss-101}
@{ " clear " link gloss-30}                                   @{ " PAL " link gloss-102}
@{ " CLI " link gloss-40}                                     @{ " parallel port " link gloss-103}
@{ " clipping " link gloss-32}                                @{ " Paula " link gloss-104}
@{ " clock " link gloss-33}                                   @{ " PIC " link gloss-105}
@{ " collision " link gloss-34}                               @{ " pitch " link gloss-106}
@{ " color descriptor words " link gloss-35}                  @{ " pixels " link gloss-107}
@{ " color indirection " link gloss-36}                       @{ " playfield " link gloss-108}
@{ " color palette " link gloss-39}                           @{ " playfield object " link gloss-109}
@{ " color register " link gloss-38}                          @{ " playfield animation " link gloss-21}
@{ " color table " link gloss-39}                             @{ " pointer register " link gloss-111}
@{ " Command Line Interface (Shell or CLI) " link gloss-40}   @{ " polarity " link gloss-112}
@{ " composite video " link gloss-41}                         @{ " potentiometer " link gloss-113}
@{ " controller " link gloss-42}                              Q
@{ " coordinates " link gloss-43}                             @{ " quantization noise " link gloss-114}
@{ " copper " link gloss-44}                                  R
@{ " coprocessor " link gloss-45}                             @{ " RAM " link gloss-115}
@{ " cursor keys " link gloss-46}                             @{ " raster " link gloss-116}
@{ " cycle strobe " link gloss-47}                            @{ " read-only " link gloss-117}
D                                         @{ " request " link gloss-118}
@{ " data " link gloss-48}                                    @{ " resolution " link gloss-119}
@{ " data fetch " link gloss-49}                              @{ " ROM " link gloss-120}
@{ " delay " link gloss-50}                                   S
@{ " Denise " link gloss-51}                                  @{ " sample " link gloss-121}
@{ " depth " link gloss-52}                                   @{ " sampling rate " link gloss-122}
@{ " device " link gloss-53}                                  @{ " sampling period " link gloss-123}
@{ " Digital-to-Analog Converter (DAC) " link gloss-54}       @{ " scroll " link gloss-124}
@{ " Direct Memory Access (DMA) " link gloss-55}              @{ " SCSI " link gloss-125}
@{ " display field " link gloss-56}                           @{ " serial port " link gloss-126}
@{ " display mode " link gloss-57}                            @{ " set " link gloss-127}
@{ " display time " link gloss-58}                            @{ " Shell " link gloss-128}
@{ " display window " link gloss-59}                          @{ " slave " link gloss-129}
@{ " DMA " link gloss-55}                                     @{ " slot " link gloss-130}
@{ " DMA latency " link gloss-61}                             @{ " sprite " link gloss-131}
@{ " dual-playfield mode " link gloss-62}                     @{ " strobe address " link gloss-132}
E                                         T
@{ " Enhanced Chip Set (ECS) " link gloss-63}                 @{ " task " link gloss-133}
@{ " equal-tempered scale " link gloss-64}                    @{ " termination " link gloss-134}
@{ " Exec " link gloss-65}                                    @{ " timbre " link gloss-135}
F                                         @{ " timeout " link gloss-136}
@{ " Fast RAM " link gloss-66}                                @{ " transparent " link gloss-137}
@{ " font " link gloss-67}                                    @{ " tri-state " link gloss-138}
@{ " frequency " link gloss-68}                               U
@{ " frequency modulation " link gloss-69}                    @{ " UART " link gloss-139}
G                                         V
@{ " genlock " link gloss-70}                                 @{ " video priority " link gloss-140}
@{ " grant " link gloss-71}                                   @{ " video display " link gloss-141}
H                                         W
@{ " HAM " link gloss-76}                                     @{ " write-only " link gloss-142}
@{ " hidden cycles " link gloss-73}                           @{ " word " link gloss-143}
@{ " high " link gloss-74}                                    Z
@{ " high resolution (Hires) " link gloss-75}                 @{ " Zorro " link gloss-144}
@{ " hold-and-modify (HAM) " link gloss-76}
@ENDNODE

@NODE Gloss-1 "Glossary / address"
A byte-numbered memory location.  The Zorro II bus is based on a 24-bit
address, the Zorro III bus on a 32-bit address.


@ENDNODE

@NODE Gloss-2 "Glossary / Agnus"
One of the three main Amiga custom chips.  Contains the blitter, copper,
and DMA circuitry.


@ENDNODE

@NODE Gloss-3 "Glossary / aliasing distortion"
A side effect of sound sampling, where two additional frequencies are
produced, distorting the sound output.


@ENDNODE

@NODE Gloss-4 "Glossary / Alt keys"
Two keys on the keyboard to the left and right of the Amiga keys.


@ENDNODE

@NODE Gloss-5 "Glossary / Amiga keys"
Two keys on the keyboard to the left and right of the space bar.


@ENDNODE

@NODE Gloss-6 "Glossary / AmigaDOS"
The disk operating system (DOS) used by Amiga computers.


@ENDNODE

@NODE Gloss-7 "Glossary / amplitude"
In audio applications, the voltage or current output expressed as volume
from a sound speaker.


@ENDNODE

@NODE Gloss-8 "Glossary / amplitude modulation"
In audio applications, a means of producing complex audio effects by using
one audio channel to alter the amplitude of another.


@ENDNODE

@NODE Gloss-9 "Glossary / arbitration"
The unambiguous selection of one request out of a number of possible
simultaneous requests for a resource.  There are two kinds of arbitration
in a Zorro III system; bus arbitration and quick interrupt arbitration.


@ENDNODE

@NODE Gloss-10 "Glossary / asserted"
The active state of a state, regardless of its logic sense.


@ENDNODE

@NODE Gloss-11 "Glossary / atomic cycle"
A cycle or set of cycles that are uninterruptable, and thus treated as a
unit; both Multiple Transfer and LOCKed cycles are considered atomic under
the Zorro III bus.


@ENDNODE

@NODE Gloss-12 "Glossary / attach mode"
1. With sprites, a mode in which a sprite uses two DMA channels for
additional colors.   2. In sound production, combining two audio channels
for frequency/amplitude modulation or for stereo sound.


@ENDNODE

@NODE Gloss-13 "Glossary / AUTOCONFIG(TM) "
>From "automatic configuration," the Zorro bus specification for how
software and hardware cooperate to permit PIC addresses to be set by
software and PIC type information to be determined by software.


@ENDNODE

@NODE Gloss-14 "Glossary / automatic mode"
1. With sprites, the normal mode in which the sprite DMA channel
automatically retrieves and displays all of the data for a sprite.   2. In
audio applications, the normal mode in which the audio DMA channels
automatically retrieve sound data.


@ENDNODE

@NODE Gloss-15 "Glossary / backplane"
The cage or motherboard subsection into which PICs are inserted.  The
Amiga 2000 and Amiga 3000 computers have integral backplanes, the Amiga
500 and Amiga 1000 computers require add-on backplane cages for Zorro II
compatibility.


@ENDNODE

@NODE Gloss-16 "Glossary / barrel shifter"
Blitter circuit that allows movement of images on pixel boundaries.


@ENDNODE

@NODE Gloss-17 "Glossary / baud rate"
Rate of data transmission through a serial port.


@ENDNODE

@NODE Gloss-18 "Glossary / beam counters"
Registers that keep track of the position of the video beam.


@ENDNODE

@NODE Gloss-19 "Glossary / bitmap"
An image made up of pixels.  A bitmap is a complete definition for a video
display consisting of one or more bitplanes stored in memory.


@ENDNODE

@NODE Gloss-20 "Glossary / bitplane"
A contiguous area of memory set aside for the video display and logically
organized as if it were a rectangular shape.  All displays consist of one
or more bitplanes; each additional bitplane doubles the number of colors
that can be displayed.


@ENDNODE

@NODE Gloss-21 "Glossary / bitplane animation"
A means of animating the display by moving around blocks of playfield data
with the blitter.


@ENDNODE

@NODE Gloss-22 "Glossary / blanking interval"
Time period when the video beam is outside the display area.


@ENDNODE

@NODE Gloss-23 "Glossary / blitter"
An Amiga coprocessor with its own DMA channel used for data copying and
line drawing.


@ENDNODE

@NODE Gloss-24 "Glossary / burst"
A short name for Multiple Transfer Cycle mode.  Essentially, within one
full Zorro III cycle there can be any number of Multiple Transfer Cycles.
Each full cycle has a complete 32-bit address supplied and a complete
32-bit datum transferred.  Each burst cycle supplies only the 8-bit page
address, but transfers a complete 32-bit datum faster than the standard
full cycle would allow.


@ENDNODE

@NODE Gloss-25 "Glossary / bus cycle"
One complete bus transaction, indicated by the assertion of at least one
cycle strobe.  For any single bus cycle, there is one address, one data
value, one data direction, and one cycle type in effect.


@ENDNODE

@NODE Gloss-26 "Glossary / bus hogging"
When a bus master takes over the bus for an undue amount of time.  The
Zorro II bus leaves it completely up to the individual PIC to avoid bus
hogging; the Zorro III bus schedules PICs with the bus controller to
evenly distribute the bus load.


@ENDNODE

@NODE Gloss-27 "Glossary / bus starvation"
When a master can't get access to the bus, it is said to be starved.  On
the Zorro II bus, two busy masters can completely starve a third master.
Complete starvation is impossible on the Zorro III bus, though a bus
hogging Zorro II card can cause similar symptoms.


@ENDNODE

@NODE Gloss-28 "Glossary / byte   "
A collection of eight signals into a logical group, and the smallest
independently addressable quantity on the Zorro bus.


@ENDNODE

@NODE Gloss-29 "Glossary / Chip RAM"
The area of memory accessible to the Amiga's custom chip set used for
graphics and sound data.  The amount of Chip RAM varies from 512K to 2
megabytes depending on the Amiga model.  See @{" Fast RAM " link gloss-66}.


@ENDNODE

@NODE Gloss-30 "Glossary / clear"
1. To change a bit or flag to 0, its off or disabled state. Opposite of
set.   2. To erase a screen or window display.


@ENDNODE

@NODE Gloss-32 "Glossary / clipping"
When a portion of a sprite is outside the display window and thus is not
visible.


@ENDNODE

@NODE Gloss-33 "Glossary / clock"
A free running signal driven at a fixed frequency to the bus, used mainly
for clocking state machines on Zorro II cards.


@ENDNODE

@NODE Gloss-34 "Glossary / collision"
A means of detecting when sprites, playfields, or playfield objects
attempt to overlap in the same pixel position or attempt to cross some
pre-defined boundary.


@ENDNODE

@NODE Gloss-35 "Glossary / color descriptor words"
Pairs of words that define each line of a sprite.


@ENDNODE

@NODE Gloss-36 "Glossary / color indirection"
The method used by the Amiga for coloring individual pixels.  For each
pixel, a binary number is formed from corresponding bits in each bitplane
which refers to one of the 32 color registers.


@ENDNODE

@NODE Gloss-38 "Glossary / color register"
One of 32 hardware registers containing colors that you can define.  In
general, each color register can be set to one of 4,096 colors from the
Amiga's palette.


@ENDNODE

@NODE Gloss-39 "Glossary / color table"
The set of 32 color registers.


@ENDNODE

@NODE Gloss-40 "Glossary / Command Line Interface (Shell or CLI)"
A means of communicating with a computer by typing commands at the
keyboard. On the Amiga, this is called the Shell and, along with Workbench
and ARexx, is one of the three built-in user interfaces.  Before the Shell
was available, this interface was called the CLI.


@ENDNODE

@NODE Gloss-41 "Glossary / composite video"
A video signal, transmitted over a single coaxial cable, which includes
both picture and sync information.


@ENDNODE

@NODE Gloss-42 "Glossary / controller"
Hardware device, such as a mouse, joystick, or light pen, used to move the
pointer or furnish other input to the system.


@ENDNODE

@NODE Gloss-43 "Glossary / coordinates"
A pair of numbers shown in the form (x,y), where x is an offset from the
left side of the display or display window and y is an offset from the top.


@ENDNODE

@NODE Gloss-44 "Glossary / copper"
Display-synchronized coprocessor that resides on one of the Amiga custom
chips and directs the graphics display.


@ENDNODE

@NODE Gloss-45 "Glossary / coprocessor"
An extra processor that enhances system performance by doing a specialized
task, such as graphics or math, very quickly.  This frees the main
processor to do other work.  Every Amiga has at least three coprocessor
chips named Paula, Agnus, and Denise to handle graphics and audio.


@ENDNODE

@NODE Gloss-46 "Glossary / cursor keys"
The four keys with directional arrows on them (found below the Del and
Help keys on the Amiga).


@ENDNODE

@NODE Gloss-47 "Glossary / cycle strobe"
A bus signal that defines the boundary of a bus cycle; the Zorro II and
Zorro III modes on a Zorro III bus each have their own cycle strobes.  The
current bus master always asserts the cycle strobes.


@ENDNODE

@NODE Gloss-48 "Glossary / data"
The contents of a memory location.  The main purpose of a bus cycle is to
transfer data between two locations.  The Zorro II bus is based on a
16-bit data path, the Zorro III bus is based on a 32-bit data path.


@ENDNODE

@NODE Gloss-49 "Glossary / data fetch"
The number of words fetched for each line of the display.


@ENDNODE

@NODE Gloss-50 "Glossary / delay"
In playfield horizontal scrolling, specifies how many pixels the picture
will shift for each display field.  Delay controls the speed of scrolling.


@ENDNODE

@NODE Gloss-51 "Glossary / Denise"
One of the three main Amiga custom chips.  Contains the circuitry for the
color pallete, sprites, and video output.


@ENDNODE

@NODE Gloss-52 "Glossary / depth"
Number of bitplanes in a display.  Each additional bitplane doubles the
number of colors that can be displayed.


@ENDNODE

@NODE Gloss-53 "Glossary / device"
A PIC; e.g., a Zorro bus master or bus slave.


@ENDNODE

@NODE Gloss-54 "Glossary / Digital-to-Analog Converter (DAC)"
A device that converts a binary quantity to an analog level.


@ENDNODE

@NODE Gloss-55 "Glossary / Direct Memory Access (DMA)"
.nh An arrangement that allows coprocessors or other system devices to
read or write memory directly, without having to interrupt the main
processor. Devices that have direct access to Zorro III slaves are said to
have DMA capability.  These devices are also called masters. .hy 14


@ENDNODE

@NODE Gloss-56 "Glossary / display field"
One complete scanning of the video beam from top to bottom of the video
display screen.


@ENDNODE

@NODE Gloss-57 "Glossary / display mode"
One of the basic types of display; for example, high or low resolution,
interlaced or non-interlaced, single or dual playfield.


@ENDNODE

@NODE Gloss-58 "Glossary / display time"
The amount of time to produce one display field, approximately 1/60th of a
second.


@ENDNODE

@NODE Gloss-59 "Glossary / display window"
The portion of the bitmap selected for display. Also, the actual size of
the on-screen display.


@ENDNODE

@NODE Gloss-61 "Glossary / DMA latency"
This is the time between a bus request and a bus grant as seen by a PIC
wishing to become bus master.


@ENDNODE

@NODE Gloss-62 "Glossary / dual-playfield mode"
A display mode that allows you to manage two separate display memories,
giving you two separately controllable displays at the same time.


@ENDNODE

@NODE Gloss-63 "Glossary / Enhanced Chip Set (ECS)"
The upgraded versions of the Amiga's Agnus and Denise coprocessor chips.
The ECS offers new display modes and expands the Amiga's graphic
capabilities. Many of the benefits of the ECS are available only in
conjunction with Release 2 of the operating system.


@ENDNODE

@NODE Gloss-64 "Glossary / equal-tempered scale"
A musical scale in which the frequency of each tone is the 12th root of 2
higher than the tone below it.  The equal-tempered scale is used in almost
all musical styles.


@ENDNODE

@NODE Gloss-65 "Glossary / Exec"
The Amiga system module which manages memory and performs other important
low-level tasks.


@ENDNODE

@NODE Gloss-66 "Glossary / Fast RAM"
General-purpose memory used for programs and data; as opposed to Chip RAM.


@ENDNODE

@NODE Gloss-67 "Glossary / font    "
A set of letters, numbers, and symbols sharing the same size and design.


@ENDNODE

@NODE Gloss-68 "Glossary / frequency"
In audio applications, the number of times per second a waveform repeats.


@ENDNODE

@NODE Gloss-69 "Glossary / frequency modulation"
In audio applications, a means of producing complex sounds by using one
audio channel to affect the period of the waveform produced by another
channel.


@ENDNODE

@NODE Gloss-70 "Glossary / genlock"
An optional feature of the Amiga that allows you to combine an external
video source with Amiga's graphic display.


@ENDNODE

@NODE Gloss-71 "Glossary / grant"
The result of an arbitrated set of requests is a single grant; there are
grants given for both the bus and quick interrupts.


@ENDNODE

@NODE Gloss-73 "Glossary / hidden cycles"
Cycles that occur on the local bus of a system, but can't be seen by
devices on the expansion bus.


@ENDNODE

@NODE Gloss-74 "Glossary / high"
A signal driven to a logical +5V state is said to be high.


@ENDNODE

@NODE Gloss-75 "Glossary / high resolution (Hires)"
A horizontal display mode in which 640 pixels are displayed across a
horizontal line in a normal-sized display.  On the Amiga a high resolution
display is often called Hires.


@ENDNODE

@NODE Gloss-76 "Glossary / hold-and-modify (HAM)"
A display mode that gives you extended color selection.  Normally, the
Amiga supports up to 32 different colors from a palette of 4,096.
Hold-and-modify (HAM mode) allows all 4,096 colors on the screen at one
time by placing some restrictions on which colors may be displayed near
each other.


@ENDNODE

@NODE Gloss-77 "Glossary / interlace mode"
A vertical display mode where 400 lines are displayed from top to bottom
of the video display in a normal-size display.


@ENDNODE

@NODE Gloss-78 "Glossary / interrupt"
An asynchronous line driven by a PIC to notify the CPU of some event,
usually some hardware event governed by that PIC.


@ENDNODE

@NODE Gloss-79 "Glossary / joystick"
A controller device with a handle that swings up, down, left, or right,
used to position something on the screen.


@ENDNODE

@NODE Gloss-80 "Glossary / light pen"
A controller device consisting of a stylus and tablet used for drawing
something on the screen.


@ENDNODE

@NODE Gloss-81 "Glossary / local bus"
The main system bus of an Amiga computer is called the local bus.  In
general, the main CPU, video chips, chip memory, and any other built-in
resources are on the local bus.  The bus controller sits on both the local
and expansion buses and manages the communications between them.


@ENDNODE

@NODE Gloss-82 "Glossary / longword"
Based on the Motorola conventions, a longword is equal to 4 bytes.


@ENDNODE

@NODE Gloss-83 "Glossary / low    "
A signal driven to a logical +0V state is said to be low.


@ENDNODE

@NODE Gloss-84 "Glossary / low resolution (Lores)"
A horizontal display mode in which 320 pixels are displayed across a
horizontal line in a normal-sized display. On the Amiga, a low resolution
display is often called Lores.


@ENDNODE

@NODE Gloss-85 "Glossary / manual mode"
Non-DMA output.  In sprites, a mode in which each line of a sprite is
written in a separate operation.  In audio applications, a mode in which
audio data words are written one at a time to the output channel.


@ENDNODE

@NODE Gloss-86 "Glossary / master"
The device currently generating addresses for the expansion bus.  There is
only one master on the bus at a time, this being insured by the bus
arbitration logic.  The master also drives data on writes, the read,
cycle, and data strobes, and several other signals.


@ENDNODE

@NODE Gloss-87 "Glossary / MIDI"
A communications standard which allows electronic music devices to share
information.  MIDI stands for Musical Instrument Digital Interface and is
endorsed by the majority of musical instrument manufacturers.


@ENDNODE

@NODE Gloss-88 "Glossary / microsecond (us)"
One millionth of second (1/1,000,000).


@ENDNODE

@NODE Gloss-89 "Glossary / millisecond (ms)"
One thousandth of second (1/1,000).


@ENDNODE

@NODE Gloss-90 "Glossary / minterm"
One of eight possible logical combinations of data bits from three
different data sources.


@ENDNODE

@NODE Gloss-91 "Glossary / modulo"
A number defining which data in memory belongs on each horizontal line of
the display.  Refers to the number of bytes in memory between the last
word on one horizontal line and the beginning of the first word on the
next line.


@ENDNODE

@NODE Gloss-92 "Glossary / motherboard"
The main system circuit board for any Amiga computer.  Resources on the
local bus of a machine are often called motherboard resources.


@ENDNODE

@NODE Gloss-93 "Glossary / mouse"
A controller device that can be rolled around to move something on the
screen; also has buttons to give other forms of input.


@ENDNODE

@NODE Gloss-94 "Glossary / multitasking"
The ability to perform more than one operation, or task, at a time.


@ENDNODE

@NODE Gloss-95 "Glossary / nanosecond (ns)"
One billionth of a second  (1/1,000,000,000).


@ENDNODE

@NODE Gloss-96 "Glossary / negated"
The inactive state of a signal, regardless of its logic sense.


@ENDNODE

@NODE Gloss-97 "Glossary / non-interlaced mode"
A display mode in which 200 lines are displayed from top to bottom of the
video display in a normal-sized display.


@ENDNODE

@NODE Gloss-98 "Glossary / NTSC"
Short for National Television Standards Committee specification for
composite video.  NTSC is the standard used for video broadcasting in the
US.  Other video standards include PAL, used widely in Europe, and SECAM.
When the Amiga is operating in an NTSC environment, the base crytal
frequency is 28.63636 MHz.


@ENDNODE

@NODE Gloss-99 "Glossary / nybble"
A collection of four bits; one half of a byte. AUTOCONFIG(TM) ROMs are
physically nybble-wide.


@ENDNODE

@NODE Gloss-100 "Glossary / overscan area"
The normally unused area surrounding a standard-size computer display. The
overscan area is important in video applications.


@ENDNODE

@NODE Gloss-101 "Glossary / paddle controller"
A game controller that uses a potentiometer (variable resistor) to
position objects on the screen.


@ENDNODE

@NODE Gloss-102 "Glossary / PAL"
Short for Phase Alternate Line.  PAL is the video broadcast standard
widely used in Europe.  Although PAL is similar to the NTSC standard used
in the US, the two systems are incompatible.  Under PAL, the base Amiga
crystal frequency is 28.37516 Mhz.


@ENDNODE

@NODE Gloss-103 "Glossary / parallel port"
A connector on the back of the Amiga that allows extra equipment such as a
printer to be attached.  The parallel port transfers data one complete
byte (8 bits) at a time, in contrast to the serial port which sends a
single bit at a time.


@ENDNODE

@NODE Gloss-104 "Glossary / Paula"
One of the three main Amiga custom chips, Paula contains audio, disk, and
interrupt circuitry.


@ENDNODE

@NODE Gloss-105 "Glossary / PIC  "
Plug-In Card.  Any Amiga expansion card is called a PIC for short.


@ENDNODE

@NODE Gloss-106 "Glossary / pitch"
1. The quality of a sound expressed as its highness or lowness.   2. The
number of characters printed in a horizontal inch.


@ENDNODE

@NODE Gloss-107 "Glossary / pixels"
The dots of light that make up the Amiga screen display.  A pixel is the
smallest unit of of display information for a given screen.


@ENDNODE

@NODE Gloss-108 "Glossary / playfield"
The background for all the other display elements on the Amiga.
Playfields provide the hardware-level logic for creating the Amiga's
display.


@ENDNODE

@NODE Gloss-109 "Glossary / playfield object"
Subsection of a playfield that is used in playfield animation.


@ENDNODE

@NODE Gloss-111 "Glossary / pointer register"
Register that is continuously incremented to point to a series of memory
locations.


@ENDNODE

@NODE Gloss-112 "Glossary / polarity"
True or false state of a bit.


@ENDNODE

@NODE Gloss-113 "Glossary / potentiometer"
An electrical analog device used to adjust some variable value.


@ENDNODE

@NODE Gloss-114 "Glossary / quantization noise"
In audio applications, noise introduced by round-off errors when you are
trying to reproduce a signal by approximation.


@ENDNODE

@NODE Gloss-115 "Glossary / RAM"
Short for random access memory.  RAM is the part of the Amiga's memory
which can be used for data storage and is directly accessible by the CPU.
RAM storage is volatile, meaning that data in RAM is lost when the Amiga
is rebooted or turned off; as opposed to ROM memory which is permanent.


@ENDNODE

@NODE Gloss-116 "Glossary / raster"
The area in memory that completely defines a bitmap display.


@ENDNODE

@NODE Gloss-117 "Glossary / read-only"
Describes a register or memory area that can be read but not written.


@ENDNODE

@NODE Gloss-118 "Glossary / request"
Asking for the use of some resource; the Zorro III bus has two kinds of
requests, bus requests and quick interrupt requests.


@ENDNODE

@NODE Gloss-119 "Glossary / resolution"
The number of pixels associated with a particular display mode.  For
example, a normal NTSC Hires screen has a resolution of 640 (horizontal)
by 200 (vertical) pixels.


@ENDNODE

@NODE Gloss-120 "Glossary / ROM "
Short for read-only memory.  ROM is the part of the Amiga's memory which
is permanent, or non-volatile.  The Amiga's operating system is stored in
ROM.


@ENDNODE

@NODE Gloss-121 "Glossary / sample"
In audio applications, a single discrete data item which represents a
waveform amplitude at a given instant.  A group of samples taken over time
is used to represent a waveform in the Amiga's memory.


@ENDNODE

@NODE Gloss-122 "Glossary / sampling rate"
The number of samples played per second.  Also used to mean the rate at
which the samples were originally recorded.


@ENDNODE

@NODE Gloss-123 "Glossary / sampling period"
The value that determines how many clock cycles it takes to play one data
sample.


@ENDNODE

@NODE Gloss-124 "Glossary / scroll"
.nh To move a playfield smoothly in a vertical or horizontal direction.



@ENDNODE

@NODE Gloss-125 "Glossary / SCSI"
Acronym for Small Computer System Interface.  SCSI is a standard interface
protocol for connecting peripherals, especially hard disk drives and other
mass storage devices, to computers.

.hy 14


@ENDNODE

@NODE Gloss-126 "Glossary / serial port"
A connector on the back of the Amiga that allows extra equipment such as a
printer to be attached.  The serial port transfers data one single bit at
a time in contrast to the parallel port which sends one complete byte (8
bits) at a time.


@ENDNODE

@NODE Gloss-127 "Glossary / set   "
To change a bit or flag to 1, its on or enabled state.; as opposed to
clear.


@ENDNODE

@NODE Gloss-128 "Glossary / Shell"
The command line interface used to send typed commands to the Amiga.  One
of the three user interfaces built into the Amiga.


@ENDNODE

@NODE Gloss-129 "Glossary / slave"
The device currently responding to the address on the expansion bus. There
is only one slave on the bus at a time; an error is signalled by the bus
collision detect logic if multiple slaves respond to the same address.
The slave also drives data on reads, the transfer acknowledge strobe, and
several other signals.


@ENDNODE

@NODE Gloss-130 "Glossary / slot"
A physical port on a Zorro backplane, which supplies independent /SLAVEn
/BRn, and /BGn lines, chained /CFGINn and /CFGOUTn lines, and is
mechanically manifested as a 100 pin single-piece connector.


@ENDNODE

@NODE Gloss-131 "Glossary / sprite"
Easily movable graphics object that is produced by one of the eight sprite
DMA channels and is independent of the playfield display.


@ENDNODE

@NODE Gloss-132 "Glossary / strobe address"
An address you put out to the bus in order to cause some other action to
take place; the actual data written or read is ignored.


@ENDNODE

@NODE Gloss-133 "Glossary / task   "
A software function spawned by a process.  Each task is an operating
system module or application program which is running and that has full
control over its own virtual 68000 machine.


@ENDNODE

@NODE Gloss-134 "Glossary / termination"
Circuitry attached to a bus signal in order to minimize annoying analog
things like ringing, reflections, crosstalk, and possibly random logic
conditions which can arise when a bus is undriven.


@ENDNODE

@NODE Gloss-135 "Glossary / timbre"
The distinctive quality of a sound produced by its overtones.



@ENDNODE

@NODE Gloss-136 "Glossary / timeout"
A bus cycle terminated by the bus controller instead of by a responding
slave device.  If no slave responds to a bus cycle within a reasonable
time period, the bus controller will terminate the cycle to prevent lockup
of the system.



@ENDNODE

@NODE Gloss-137 "Glossary / transparent"
In graphics, a special color register definition that allows a background
color to show through.  Used in dual-playfield mode.


@ENDNODE

@NODE Gloss-138 "Glossary / tri-state"
A signal driven to a high impedence condition is said to be tri-stated.


@ENDNODE

@NODE Gloss-139 "Glossary / UART"
The circuit that controls the serial link to peripheral devices, short for
Universal Asynchronous Receiver/Transmitter.


@ENDNODE

@NODE Gloss-140 "Glossary / video priority"
Defines which graphic objects (playfields and sprites) are shown in the
foreground and which objects are shown in the background when they occupy
the same area of the display.  Higher-priority objects appear in front of
lower-priority objects.


@ENDNODE

@NODE Gloss-141 "Glossary / video display"
Everything that appears on the screen of a video monitor or television.


@ENDNODE

@NODE Gloss-142 "Glossary / write-only"
Describes a register that can be written to but cannot be read.


@ENDNODE

@NODE Gloss-143 "Glossary / word"
Based on the Motorola conventions, a word is equal to 2 bytes.


@ENDNODE

@NODE Gloss-144 "Glossary / Zorro"
The name given to the Amiga bus specification.  "Zorro I" refers to the
original design for A1000 backplane boxes, "Zorro II" refers to the
modification to this specification used for the A2000 and compatible
backplanes, and "Zorro III" refers to the Zorro II compatible bus
specification first used in the Amiga 3000 computer.

@ENDNODE
