"The Atari A to Z"
                              by Mark S Baines
                      Copyright (c) 1998 Mark S Baines
                             All Rights Reserved


       YOU MUST READ "READ_ME.NOW" BEFORE YOU LOOK AT ANY OF THIS FILE
*****************************************************************************


J


Jack
A recessed electrical connector into which a plug (usually round) can be 
inserted.


Jagging
In raster scan graphics where curved and diagonal lines are represented on the 
screen or in print as 'stair steps'. This is a common complaint of enlarging 
bitmapped fonts which outline fonts attempt to cure. See Bitmap image.


Jaguar
Atari games console launched in 1994. Housed in a futuristic case it is an 
interactive multi-media system based on an Atari-designed proprietary 64-bit 
RISC processor. The Jaguar features over sixteen million colours in 24-bit 
true-colour graphics and produces shaded 3D polygons which can be manipulated 
in real-time. There is also real-time texture mapping and other special video 
effects. The sound system is based around a DSP as in the Falcon, being of 16-
bit stereo CD quality.

There is a 32-bit expansion port which will allow for future connection into 
cable and telephone systems, an external DSP port for modem use and connection 
to other digital audio devices, such as DAT players. A double-speed CD player 
peripheral will play ordinary audio CDs, CD+G (Karaoke) and Kodak's Photo-CD. 
A Power Pad Controller with a ten-key pad and other special features is used 
to control the Jaguar.

The Jaguar has won many awards and is generally accepted to be many years 
ahead of the competition. With its release all computer development stopped at 
Atari after TOS 4.04 and the Falcon030. At the time of writing, all Atari's 
future rests on the success of the Jaguar.


JANET
Joint Academic NETwork. A UK-based communications network system which 
connects computers from educational and scientific research establishments 
allowing for the exchange of information.


JEIDA
Japanese Electronic Industry Development Association. A Japanese organization 
that sets standards for electronics products.


Joker
See Wildcard.


Joystick
An operator control device for moving display elements on a screen, often in 
two directions at once. Commonly used as a means of sprite control in games. 
It normally consists of an upright hand-held control which can operate four 
switches in the up, down, left and right positions. Some may provide another 
four between these but most software is capable of detecting the closing of 
two adjacent switches at once giving eight positions in all. Another switch is 
provided for the 'Fire' button. A Ground signal and +5 V signal normally 
complete the set. Some joysticks are analogue devices in that they provide an 
indication of how far the joystick is moved in any one direction rather than 
just the on/off state of normal devices. Ports to accommodate these are 
provided on the STE, Mega STE and Falcon and have 15-pin D connectors rather 
than the nine pins of normal joysticks. These ports have 8-bit resolution on 
each axis and are bidirectional so that they can be written to as well as read 
from. This provides some scope for device control through these ports, such as 
with robots and monitoring instrumentation.


JPEG
Joint Photographic Expert Group or Joint Picture Expert Group. An organization 
set up to set the technical standard for still image (true-colour) 
compression. JPEG file have the .JPG file name extender and use lossy 
compression methods where huge savings in disk storage can be had. See 
Compression.


Jump
Also, branch. To stop executing one sequence of instructions in a program and 
commence another.


Jumper
A wire, cable or small connector used to make a short distance bridge between 
two electrical terminals.


Justify
In print preparation, to format the text so that lines are of equal length 
with left and right margins vertically aligned. This often means the addition 
of spaces or microspaces between words and sometimes between letters on a 
line. Left justification is where the left margin of text is aligned only, the 
right margin being ragged. Right justification is usually where the right 
margin is aligned and the left is ragged, but is often used, incorrectly, to 
denote full justification. Full justification is where both margins are 
aligned as in this paragraph.


J
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