"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
*****************************************************************************
F
Face
The term used to refer to graphic characters to identify type or style, as in
italic face.
Facsimile
See FAX.
Fail safe
To fail in such a way so that no data loss or dangerous condition results.
Failure
A complete loss of a function or facility.
Falcon030
The Atari Falcon030 is the latest of the Atari range of TOS compatible
computers using a 16 MHz MC68030 processor (switchable to 8 MHz), an optional
MC68881/2 FPU, a 16 MHz BLiTTER and a 32 MHz Digital Signal Processor (DSP).
There is a 512 K ROM and up to 16 Mb of RAM (2 Mb of the 16 Mb is masked out
as a ST memory map image and I/O space to retain downwards compatibility and
direct peripheral and DSP memory mapping) with an optional internal 2.5 inch
hard disk drive and a 1.44 Mb HD floppy disk drive. Two internal expansion
slots are provided, one for the memory card and the other is the processor
direct slot for third party expansion boards, such as for IBM PC 386 emulation
and JPEG and MPEG video boards. The RAM expansion board is custom designed and
has 32 sockets that can accept either eight 256 K x 4 DIP DRAMs at 80 ns, or
eight 1 Mb x 4 DIP DRAMs at 80 ns, or 32 1 Mb x 4 DIP DRAMs at 80 ns, giving
1, 4, or 16 (14) Megabytes of RAM, all on one board. TOS 4 and MultiTOS are
used with the NewDesk Desktop and the Falcon is TOS compatible. Many other
ports are similar to those of the Mega STE and TT.
What particularly makes this computer interesting is the very sophisticated
digital processing and audio subsystem. Eight track, stereo 16-bit digital
input and output via stereo jacks are available with sampling rates up to 50
kHz (better than CD quality sound), making direct sampling to disk possible
with software! The inclusion of the DSP gives very fast processing of any
digital data independent of the CPU, so that as well as digital sound
manipulation, images and graphic material can also be processed with speed.
The video output is VGA standard with a resolution of 640 x 480 and 256
colours. The true-colour modes are 16-bit 640 x 480 x 65,536 colours
(interlaced on TV or ST style monitors) and 15-bit overlay 640 x 480 x 32,768
mode which allows for easy video titling and special effects. True-colour 320
x 480 is available on VGA monitors. ST compatible modes are also available.
All video modes are capable of being Genlocked to provide multimedia
capabilities on monitors and television and the true-colour modes directly
support overlays. Programmable overscan is also available so that the 320 x
200 x 256 colour display can give a 384 x 240 screen and the highest
resolution is 768 x 480 with overscan in true-colour mode.
The first Falcon030s came in a dark grey 1040STE style case but later versions
reverted to the Atari grey colour. The style of case has always been generally
disliked by developers and customers. At one point a 'consumer' version
featuring a new casing was expected as was a two-piece, separate keyboard
version. Both are now unlikely to appear from Atari. The Falcon040 has also
been spoken about and apparently in development at Atari at one time, and was
to cater for the business and serious home user. It would have used a fast
68040 CPU, had more RAM and existed in a more traditional three-box case like
that of the TT.
There has been much argument about the sizes of the data and address buses on
the Falcon. All Atari documents say that the bus is 32 bits wide. However,
examination of the motherboard suggests that the address bus is only 24 bits
wide for the RAM expansion slot only has that number of lines. The data bus is
generally 16 bits wide into and out of the CPU but the connection between the
COMBEL and VIDEL chips and the RAM is 32 bits wide. The 68030 CPU therefore
has to do dynamic bus resizing to get a 32-bit word as two 16-bit words. The
video data is taken from the 32-bit wide side of COMBEL enabling a higher
bandwidth suitable for the high resolution/colour modes.
Argument also continues on Atari's definition of true-colour, whether true-
colour can be anything less than 24-bit colour.
In December 1994, it was announced that C-LAB Digital Media (a German company
that released Notator, Creator and Unitor) had signed a worldwide licence
agreement to manufacture, market and distribute workstation products based on
the Falcon into the professional audio and musical instrument markets. The
first machine they aim to produce (at the time of writing) is a standard
Falcon with professional quality audio circuitry (what are currently referred
to as the Cubase mods) and adequate memory and SCSI hard drive capacity. It is
known as the C-LAB Falcon Mk II. They also hope to have a cheap entry level
machine and a 68040 prototype is supposedly in an advanced stage as well as an
enhanced Desktop and a 19 inch rackmount version. This development confirms
the view of many that Atari's future lies with games machines, such as the
Jaguar, and that they have no plans to produce any more computers for the
foreseeable future.
See Falcon video. Also see DMA sound, Sampling, DSP, MultiTOS, Expansion bus,
Falcon video, Falcon audio.
Table F1: Falcon Specification
Processor 16 MHz MC68030 separate on-chip 256 byte instruction and
data caches
Optional 16 MHz MC68881/2 FPU
32 MHz MC56001 Digital Signal Processor
16 MHz 16-bit BLiTTER
DMA
Performance 3.84 MIPS
Bus Two independent 32-bit data and 24-bit address buses
RAM 1, 4 or 14 Mb operating in page mode, 32-bit wide but not
nybble/burst mode as in TT RAM
ROM 1 socketed 4 Mbit ROM providing 512 K of ROM space
Hard Disk Drive Internal optional 2.5" drives on IDE bus, 65 Mb, 85 Mb,
120 Mb, 200 Mb
Floppy Disk Drive 3.5" double-sided high density 1.44 Mb
Input/Output MIDI in and out (5-pin DIN)
Analog RGB monitor port (19-pin DB VGA) for VGA monitors,
ST monochrome or colour monitors (via adaptor plug) with
Genlock support
RF modulator for TV or video (RCA)
Bidirectional parallel printer port (25-pin DB)
High-speed SCC serial port (9-pin DB)
SCC LAN (8-pin mini-DIN)
SCSI II with DMA (50-pin connector)
ST compatible cartridge port (128 K)
2 digital/analog controller ports (15-pin DB)
ST joystick (9-pin DB)
ST mouse (9-pin DB)
Digital audio/DSP connector (26-pin DB)
Stereo microphone input (mini-jack)
Stereo headphones output (mini-jack)
Internal RAM board slot (30 + 50-pin)
Processor direct slot (30 + 50-pin)
Internal IDE hard disk connection (44-pin)
Video See Falcon video. Some examples:
Colour palette of 4,096 colours
320 x 200 x 16 colours ST low resolution
640 x 200 x 4 colours ST medium resolution
640 x 400 x 2 colours ST high resolution
TV/video colour palette of 262,144 colours
640 x 400 x 65,536 colours (16-bit)
640 x 400 x 32,768 colours (15-bit overlay mode)
VGA palette of 262,144 colours
640 x 480 x 256 colours
320 x 480 x true-colour
Programmable overscan
All modes can be Genlocked. True-colour modes support
overlays
Hardware assisted fine scrolling
Sound Stereo 16-bit digital DMA audio output
Stereo 16-bit digital DMA audio input
8 channel 16-bit PCM digital record/playback
Stereo 8-bit PCM sound (compatible with TT, STE and Mega
STE)
3 channel PSG sound (compatible with ST)
Total MIDI compatibility
Internal mono speaker (which can be disabled)
Keyboard Integral QWERTY keyboard, 95 keys, numeric keypad, cursor
keys, 10 function keys, (support for 300 dpi mouse)
Mouse 128 dpi 2 button
Real-Time Clock Rechargeable battery backed RTC with 50 bytes of non-
volatile RAM
Power Internal PSU
Operating System TOS 4 with GEM and NewDesk Desktop in ROM
Falcon audio
The Falcon has a sophisticated digital processing and audio system centred
around a 32 MHz Motorola 56001 Digital Signal Processor or DSP. Separate eight
channel (four stereo), 16-bit digital sound record and playback channels which
can operate in parallel with each other are provided, making it possible to
record eight channel 16-bit stereo data and play back a different four
channels of 16-bit stereo data simultaneously using the SoundDMA. All this is
independent of any other processor or task. A separate, third party, external
DSP device providing the extra ADCs and DACs with the timing crystals for CD
44.1 kHz and DAT 48 kHz sampling rates will be required for full eight track
recording and editing. A 16-bit stereo Codec provides a stereo DAC and ADC.
The DAC output is directed to the internal loudspeaker (which can be turned
off), to the monitor port (for monitors with a built-in speaker) and the
stereo headphones jack on the back panel. The DAC attenuation can be
controlled for left and right channels independently through operating system
calls. The 16-bit stereo ADC is connected to the microphone jack on the back
panel and its gain can be controlled by operating system calls. The PSG chip
signals can also be fed to the ADC input. All this is linked together with a
data path matrix, the DSP send and receive, DMA record and playback, CODEC and
input and output external connectors can all be connected in any way so that
any receiving device can have its data path connected to any one source
device. All data transfers are serial data paths which include a bit clock,
data and synchronization signal.
There are three possible clock signals, internal 25.175 MHz and 32 MHz and an
external clock. The CODEC can only use the internal 25.175 MHz or external
clock. The bit clock is taken from the master clock divided by a programmable
value of four to 24, in increments of four. The sample rate is the bit rate
divided by 128 giving room for eight 16-bit samples per sample period. A
sample rate of 49.17 kHz (50 kHz) can be obtained from the 25.175 MHz clock
signal and 62.5 kHz from the 32 MHz master clock. However, the CODEC cannot
support this sampling rate as it cannot use the 32 MHz clock signal. The
25.175 MHz clock is used to support STE compatible 50 kHz, 25 kHz and 12.5 kHz
sound sample rates. The 32 MHz clock can be used to provide an 8 MHz bit rate
(1 Mb per second) which is the maximum transfer rate of the DSP external
interface. The external clock comes from the DSP connector and third party
developers provide the necessary interface box (for instance, AES/EBU SPDIF
interfaces which allow direct connection to DAT players and CD mastering
recorders) with the crystal necessary to obtain a sampling rate of 44.1 kHz
(CD quality) from a 22.5792 MHz signal and 48.0 kHz (DAT quality) from a
24.576 MHz signal.
The DMA record and playback channels have a maximum data transfer rate of 1 Mb
per second. The DMA input channel provides a fast path to system memory with a
32-byte FIFO on the data path which is synchronized with a memory addressing
module which can fill memory in linear, continuous or looping mode. The DMA
output channel provides a fast data channel from system memory to subsystem
devices also with a 32-byte FIFO which ensures that it can keep up with the
real-time response required by certain devices, such as the CODEC DACs.
The DSP system has many features which make it ideal for audio processing but
the data being processed can also be video, graphics, and any other general
purpose data. Some possible applications include tone generation, noise
cancellation, pattern recognition, image enhancement, animation, spectral
analysis, speech processing, recognition and synthesis, voice mail, acoustic
equalizer, digital pre-amplifier and music synthesis. A high-speed software
modem is possible with direct connection of the DSP port to the telephone
socket.
Falcon video
There are just too many resolutions to give each resolution a name. In the
table below, TV/RGB means any video screen (such as a TV) and analog RGB
monitor (such as the Atari SC1224 or even a SM124/5). VGA means any standard
VGA monitor. Monitor adapters are necessary that plug into the monitor port to
inform the Falcon what kind of monitor is attached. Adapters for 15-pin VGA,
Atari SC and SM series monitors, SCART/Peritel cables and for composite
video/mixed audio are available. Interlace mode shows the odd numbered lines
on one vertical scan, and then the even numbered lines on the following
refresh, allowing for persistence of the phosphors to hold the first scan on
the screen, thus interlacing or mixing the two to get twice as many lines.
However, it takes two screen refreshes to draw one screen, therefore making
that frame frequency half of a non-interlaced screen. Unless this frequency is
very high in the first place, this causes flickering and uncomfortable
viewing.
VGA modes are not interlaced. There is a line-doubling mode where 240 lines
are used in memory and shown on the screen but each one is displayed twice,
doubling up the raster lines to 480 to fill the screen. As each consecutive
pair of lines is the same, there is no extra information displayed on the
screen as with interlace mode. 640 x 240 is the true resolution in this mode
even though 480 raster lines appear on the screen. This mode is a way of
halving the memory use of the screen in situations where memory is a
constraint.
Table F2: Falcon Video Modes
From a palette of 262,144 colours:
40 column modes
4 colour normal TV/RGB: 320 x 200 4 colours 2 planes
16 colour normal TV/RGB: 320 x 200 16 colours 4 planes
256 colour normal TV/RGB: 320 x 200 256 colours 8 planes
True-colour normal TV/RGB: 320 x 200 true-colour
4 colour interlace TV/RGB: 320 x 400 4 colours 2 planes
16 colour interlace TV/RGB: 320 x 400 16 colours 4 planes
256 colour interlace TV/RGB: 320 x 400 256 colours 8 planes
True-colour interlace TV/RGB: 320 x 400 true-colour
4 colour normal VGA: 320 x 480 4 colours 2 planes
16 colour normal VGA: 320 x 480 16 colours 4 planes
256 colour normal VGA: 320 x 480 256 colours 8 planes
True-colour normal VGA: 320 x 480 true-colour
4 colour line-doubling VGA: 320 x 240 4 colours 2 planes
16 colour line-doubling VGA: 320 x 240 16 colours 4 planes
256 colour line-doubling VGA: 320 x 240 256 colours 8 planes
True-colour line-doubling VGA: 320 x 240 true-colour
80 column modes
2 colour normal TV/RGB: 640 x 200 2 colours 1 plane
4 colour normal TV/RGB: 640 x 200 4 colours 2 planes
16 colour normal TV/RGB: 640 x 200 16 colours 4 planes
256 colour normal TV/RGB: 640 x 200 256 colours 8 planes
True-colour normal TV/RGB: 640 x 200 true-colour
4 colour interlace TV/RGB: 640 x 400 4 colours 2 planes
16 colour interlace TV/RGB: 640 x 400 16 colours 4 planes
256 colour interlace TV/RGB: 640 x 400 256 colours 8 planes
True-colour interlace TV/RGB: 640 x 400 true-colour
2 colour normal VGA: 640 x 480 2 colours 1 plane
4 colour normal VGA: 640 x 480 4 colours 2 planes
16 colour normal VGA: 640 x 480 16 colours 4 planes
256 colour normal VGA: 640 x 480 256 colours 8 planes
4 colour line-doubling VGA: 640 x 240 4 colours 2 planes
16 colour line-doubling VGA: 640 x 240 16 colours 4 planes
256 colour line-doubling VGA: 640 x 240 256 colours 8 planes
ST low, ST medium and ST high resolutions are available on both VGA monitors
and analog RGB monitors where on a colour monitor ST high resolution is
achieved by using the interlace mode.
The ST monochrome monitor (SM124 or SM125) will work with the Falcon030 as
well. However, it only supports the ST high resolution mode.
All of these modes can be accessed through the GEM VDI. In the case of true-
colour mode, there is no colour palette to allow for changing the colour of
pixels that have already been drawn. The VDI provides 256 virtual pens for
drawing with, which act like the physical pens in other modes except that once
the pixel is drawn it cannot be changed using vs_color().
The 1-, 2-, 4- and 8-bit per pixel modes are arranged as they are in a ST, STE
or TT. This consists of 16 bits of each plane in adjacent words until all
planes are accounted for. The 16-bit per pixel, true-colour mode is organized
as packed pixels. Each 16-bit word contains all of the information for a
pixel. Since this mode is a true-colour mode, there is no palette to convert
the data into RGB information for the video system. The data is encoded in
each pixel as RRRRRGGGGGXBBBBB. The least significant 'G' bit ('X' bit) is
also used as the overlay bit and should not be used in graphic data.
Typically, this bit will be used to select between Falcon and externally
generated video on a pixel by pixel basis and is essentially a one bit chroma-
key for overlays and video titling. Use of the overlay bit will, of course,
drop the number of colours in true-colour mode from 65,536 to 32,768. Most
sources argue that true-colour is, in fact, 24-bit colour with over 16 million
colours on screen at a time (even though the human eye cannot differentiate
the difference between most of them). 65,536 colours is certainly a high
colour mode, but not true-colour as experienced on the Apple Mac and other
computers. However, it is adequate enough but for the most discerning video
and graphics specialist.
Overscan is available on all modes on a TV or analog RGB monitor by
multiplying the X and Y resolution by 1.2. For example, modes with 320 pixels
of horizontal resolution (X resolution) will become 384 pixels across and
modes with 640 pixels will become 768 across. Overscanning is done in the X
and Y resolution together not independently. On a VGA monitor, overscan is
'faked'. The video hardware doesn't have the capability to do overscan on a
VGA monitor. Atari made it so that if an overscan mode is set on a VGA
monitor, the normal size screen is seen but the screen is a window on to the
bigger overscanned image. This was done for compatibility. A game that has an
overscanned start-up picture can use the same picture on both the VGA monitor
and the TV or RGB monitor.
Overscan cannot be set from the Desktop. The AES and Desktop will work with it
but because the parts of the screen cannot be seen Atari thought that that
option shouldn't be available from the Desktop. However, overscan can be set
using a new XBIOS call Vsetmode().
Software can make new resolution calls whilst running, placing the machine
into a new video mode where the AES will be unavailable but the VDI is fully
supported. This is primarily for games or paint and animation packages that
will run their interface in the current user video mode, but be able to render
or output in another, say 768 x 400, true-colour mode. A preview window could
be in 16-colour mode with the application doing a wind_update() call and go to
the desired final output mode, then back to the user mode releasing
wind_update().
Two pins on the monitor port, 18 and 19, are Monitor Select 1 and 0 and are
internally pulled high and are read by the operating system to determine the
type of monitor connected. TOS then uses this information to set up video
timing values suitable for that particular monitor. The values assigned are
(where 1 is +5 V and 0 is Ground):
M1 M0 Monitor type
0 0 ST Monochrome
0 1 ST Colour
1 0 VGA
1 1 TV
Fallback
To change to a different mode of operation as a result of a failure of the
main mode.
False
One of two logic conditions represented by a 0-bit and opposite to 'true'.
Fan fold
A term applied to continuous stationery where the individual sheets are folded
successively in opposite directions forming a stack.
FAQ
Frequently Asked Questions. Commonly used shorthand in e-mail and other
messages.
Fast Fourier transform - FFT
A processing technique for improving the detection and interpretation of
signals in the presence of noise. Although a normal computer is capable of
performing such a complex task, to achieve acceptable performance in real-time
requires the presence of a digital signal processor designed for the job, such
as the Falcon030's DSP.
Fastload bit
Normally, when a program is loaded into the memory of a ST-Falcon all the RAM
has to be cleared first to accommodate it, even if it doesn't use it. Rainbow
TOS (1.4) introduced the ability to set a program for 'fastload' where a bit
in the program file header is set and tells TOS that the program can be loaded
without having all of the memory cleared for it. The only memory that is
cleared is that required by the program's uninitialized data section (BSS).
This feature is most useful on machines with a lot of memory where clearing 4
Mb or more of RAM can take several seconds. That, by itself, is not much but
this process can take some considerable time when booting up many programs
from the AUTO folder and accessories each one clearing RAM. Also, if programs
are being run from other programs (such as in a programming environment, for
instance) saving a second on each program makes the computer feel much more
responsive. MAKEFAST.PRG by Atari is a program which will set or unset the
fastload bit on any program.
Fast RAM
RAM having an access speed of 80 ns or less, or specifically the 32-bit RAM in
the TT also known as TT RAM, Alternative RAM or single purpose RAM. The video
chip can only display screen data from ST RAM and so Alternative RAM does not
have the video timing constraints of the ST or dual purpose RAM taking up any
of the cycles, so it can be made to appear faster to the processor. This RAM
uses nybble mode to facilitate burst mode filling of the 68030 caches which
means that the CPU fills its cache at one cycle per subsequent access. Fast
RAM is available on the TT only through an expansion board with its own MCU. A
board contains four SIMM slots allowing 4 Mb or 16 Mb of RAM with 1 Mbit or 4
Mbit chips. A switch on the TT can be selected to place this RAM in burst mode
and another set of jumpers can select its start address which is normally
$01000000.
Any program can run in Fast RAM providing that they do not set the screen base
address in Fast RAM or play DMA sound from there, do not try to make a device
driver do DMA from or to there (unless the driver knows about the differences
between ST RAM and Alternative RAM) and the program must not do DMA itself
from or to Fast RAM. Since programs written before the introduction of
Alternative RAM are not aware of the rules, the user must inform GEMDOS as to
whether a program is eligible to use Alternative RAM or not. A distinction can
also be made as to whether the program uses Alternative RAM for its Malloc()
calls (memory allocation function), so that a program that allocates a screen
buffer can still load into Alternative RAM but its Malloc() calls are
satisfied from ST RAM.
As of TOS 1.4, one of the reserved long words in the header of executable
files acquired a meaning. The least significant bit is the Fastload bit. The
next two bits relate to Alternative RAM use. Bit 1, when clear, means that the
program must be loaded into ST RAM and bit 2, when clear, means that any
Malloc() calls by that program must be satisfied from ST RAM. When these bits
are set, then Alternative RAM is used. If there isn't enough Fast RAM to
satisfy a request then ST RAM is used. If there isn't enough of that, the
request fails. 'Enough' is relative. Some programs have a priority on speed
rather than on memory and so 'enough' would be, say, 256 K more than its
declared requirements (text + data + BSS). Others need as much memory as
possible.
A new field in the program's header, called TPAsize, reflects the memory
requirements of the program. If the program load bit is clear (load into ST
RAM) then this field is ignored. If the program can be loaded into Alternative
RAM and there is more of this than ST RAM, the program is loaded into
Alternative RAM and this field is ignored. This field is used when Alternative
RAM is required and there is more ST RAM available, where its value determines
how much Alternative RAM is 'enough'. If there is enough alternative memory,
it loads there, if not, then in ST RAM. The value in the TPAsize field
increases in 128 K steps and is added to the declared size of the program. The
field is four bits wide and is the high four bits of the program flags long
word. The amount is the field's value times 128 K, plus 128 K so a value of
zero is 128 K. The maximum value is fifteen, meaning 2 Mb.
Programs written after the introduction of this program header long word and
Alternative RAM can use Mxalloc() instead of Malloc() for getting memory
blocks from either ST RAM or alterative RAM. See ST RAM, Malloc, Program
header.
FAT
File Allocation Table. A data structure on a disk representing a map of all
the disk's clusters (two sectors) so that the operating system knows where to
look for a certain file. Under GEMDOS, each entry is a 12-bit number which
points to the next cluster of a file, indicates whether it is the last cluster
or whether the cluster is free or unusable. GEMDOS keeps two copies of the FAT
on each disk, providing a convenient means of checking the validity of the
main one.
Father
The term applied to the first update version of a file. See Generation.
Fault
An abnormal hardware or software condition that reduces performance but not
necessarily causing a failure.
FAX
FACSimile (FAXimile). The transmission of data as images over a telephone line
and printed out as such at the receiving station. The FAX machine essentially
consists of a scanner, a modem and a printer. The original standard, Group 1,
was a very slow analogue system which could take up to six minutes to scan a
page and send a poor quality image. The Group 2 standard was faster but still
using analogue signals. A computer could not manipulate these analogue signals
and so the Group 3 standard was established which most FAX machines and FAX
modems conform to today. The document is scanned at a resolution of eight
pixels per millimetre horizontally and 3.85 pixels/mm vertically giving 203 x
98 dpi. All Group 3 machines must also be able to receive 'Fine' mode
transmissions at double the vertical resolution, i.e. 203 x 196 dpi. A minimum
data speed of 2,400 bits per second must be supported even though the most
common speed is 9,600 bps. If a reliable link is not established the data rate
can fall down to as low as 300 bps. The data is compressed to reduce the
length of transmission time.
FCC
Federal Communications Commission. A US organization which allocates
frequencies for radio communications. It also tests all electrical and
electronic equipment for radio frequency emissions issuing a certificate of
compliance to federal rules if they pass. Without this FCC approval,
electrical equipment is difficult to sell in the US. The Atari TT's
introduction into the US market was greatly delayed by failing FCC tests.
FDC
Floppy Disk Controller.
FDD
Flexible Disk Drive or Floppy Disk Drive.
Feed
To move paper through a printer.
Feedback
Returning the output of a device to its input to modify or control its
operation.
Fetch
To locate an operand or instruction in main storage and load it into a CPU
register for processing.
Fetch cycle
That part of execution in which a fetch occurs.
FF
Form Feed. ASCII character 12 used to cause a new form (page) to be displayed
on a VDU screen or more usually, to vertically tabulate a printer to the
beginning of the first line of the next sheet of paper or eject the sheet from
the printer.
FFT
Fast Fourier Transform.
FidoNet
The largest bulletin board system network in the world, mainly based on IBM PC
compatibles and consisting of around 18,000 nodes. There is a very wide choice
of conferences with large amounts of message traffic in most of them and for
the most part, access is free.
Field
In databases, that part of the record that consists of a single piece of
information used for processing, i.e. the 'name' field in an address database
file. In GEM dialog boxes, it is a single user input line requesting a
particular item of data, such as a file name. Also, that part of a display
surface to which data can be written and also where a product is sold and used
('a report from the field').
FIFO
First In First Out. An algorithm used in determining the order of access of
data elements where the next item to be processed is the one that has been
waiting the longest. It is the basis of a queue.
File
In databases, a collection of individual related records, such as an address
file. It is now synonymous with any individually accessible unit of related
storage, such as a program or data file on a disk.
File access
The process of reading data from or writing data to a file, making transfers
between RAM and backing storage.
File attribute
An item that identifies a file, such as its name, size or type of access. Also
see Attributes.
File conversion
The process of converting the format of a file to suit another computer or
program, e.g. converting a Degas PC3 image file to a GEM IMG image file.
File copy
To duplicate individual files (as opposed to a disk copy) from one storage
medium to another. See Copy.
File creation
The process of opening a new file, writing data to it and closing it.
File description
A directory entry identifying a particular file, consisting of its name and
size and the date and time of its creation or last update.
File directory
A list of files on a storage device as maintained by the operating system. On
some systems, such as GEMDOS and MS-DOS, directories may contain other
directories called subdirectories. Under GEMDOS, a directory is usually called
a 'folder'.
File menu
Usually the second menu in a GEM program where access to the disk input and
output operations on the program's data is provided. Items should normally
include "New", "Open", the "Load" and "Save" oriented operations, "Import" and
"Export", the "Printer" operations and "Quit".
File name
A character string that uniquely identifies a file within a directory. Under
TOS it consists of up to eight alphanumeric characters (not punctuation marks)
separated by a full stop from the optional three character extender.
File protect
The prevention of writing to a file by opening the disk write protect hole or
setting the file attributes to read-only. This is used as a safeguard to
accidental loss or corruption of data.
File selector
A GEM routine or a user installed TSR program that enables the user to select
files, paths and drives from presented lists when asked to input a file name
prior to a file load or save operation. A replacement for the poor built-in
TOS file selector is almost a necessity. Martin Patzel's Fselect, Little Green
Football's Little Green Selector, Selectric (all shareware) and Universal Item
Selector (commercial) are all recommended.
Filespec
File specifier. The search criterion used in a file selector when displaying
files for the user to choose from, e.g. *.DOC only shows files with the .DOC
extender.
Fill
To write a pattern of bits to a memory location, such as to colour an area of
screen display in a graphics program.
Filter
A command or program that takes input from a program, transforms it in some
way and then outputs it to the screen or a file. The filter may alter the data
in any way, such as to sort it into alphabetical order, to spell check it, to
delete every alternate word etc. Filters are often used with pipes and
redirection. See Pipes, Redirection.
Find
A program routine to search for a particular data item.
Finger
A UNIX command and consequently used across the Internet, which examines the
user log on a system for a particular name. It will also tell you if that user
is currently logged on.
Firmware
A term used for programs stored on ROMs, 'firm' being intermediate between
'software' (programs) and 'hardware' (ROM chips).
First generation computer
A computer utilizing thermionic vacuum tubes or valves, circa 1940s.
Fixed disk
A magnetic disk that cannot be removed from its housing, such as a Winchester
hard disk.
Fixed-length record
A database record that is of the same length as all other records in that
database regardless of the data it contains. Although often a waste of storage
space, it enables search operations to be quicker and makes database
management simpler.
Flag
An indicator showing the existence of a certain condition when set and the
absence of that condition when clear.
Flame
In a telecommunications network, an abusive message showing strong
disagreement or feelings towards another's message.
Flash
To blink, a state of cursors.
Flatbed plotter
A plotter in which the pen moves in two dimensions over the paper.
Flat file
A non-relational database file representation of a manual card index file.
Flat screen display
A display screen that is relatively thin in relation to its width and height,
and normally refers to non-CRT displays, such as LCD and gas plasma displays.
Flexible disk
See Floppy.
Floating point
The representation of numbers that consist of the fractional part or mantissa
(the digits) and the exponent (the position of the radix point). The exponent
is the power to which the base (normally ten) is raised e.g. 123.4 = 1.234 E2
or 1.234 02 which is equivalent to 1.234 x 10^2.
Floating point coprocessor
An integrated circuit device designed to perform floating point mathematical
calculations at optimum speed and thus relieving the CPU from those tasks. See
FPU.
FLOPS
FLoating point OPerations per Second. A measurement of the speed of operation
of a FPU.
Floppy disk
This refers to the flexible magnetic disk rather than the case that protects
it which for a 3.5 inch floppy disk is hard. A floppy disk rotates at 300 rpm
and the drive has two read/write heads, one for each surface. The track
density is usually 135 tracks per radial inch and the track to track access
time is 3 ms on a double density drive. The data transfer rate on the ST is
250 Kbits per second. Early STs had single-sided disk drives which were
replaced with double-sided ones in 1985-86 using double density format giving
720 K storage space. High density 1.44 Mb floppy disks were introduced in
1991-92 with the TT, Mega STE and Falcon030. See Disk.
Floppy disk controller - FDC
The WD1772 chip controlling the floppy disk drive on the ST range or the AJAX
chip on the TT and Falcon. It takes the disk access requests from TOS and
converts them into the electrical pulses necessary to make the disk drive's
heads seek tracks and read and write data.
Floppy disk interface
The ST-TT range have a port to accept an external floppy disk drive, such as
an Atari SF314 or a third party device. See the Connectors Appendix C.
Flow
The movement of items between two points in a stream or sequence.
Flowchart
A diagram used to aid program construction showing the movement of control
through an algorithm.
FM
Frequency Modulation.
FMail
A private message in a bulletin board system network to a specific recipient
with a separate file attached for downloading.
FMV
Full-Motion Video. A term used to describe the ability of a CD-ROM system to
store moving pictures rather than just stills.
FNet
ForemNet. An international bulletin board system network catering specifically
for the Atari range of computers and largely replaced by the TurboNet system
in 1992 in Europe. It is now mostly confined to the US.
Folder
The Atari TOS name for a subdirectory containing related files within the main
disk directory. It has its own icon which looks like a cardboard manila folder
on the Desktop.
FOLDRXXX.PRG
An official freeware Atari patch program which increases the size of the
Operating System pool of memory buffers. It is designed to overcome the
infamous 40 folder bug which is especially prevalent in TOS 1.0 and 1.2.
Although some effort has been made to lessen the symptoms of this problem, it
does still exist in all TOS versions. See Forty folder bug.
Folio
The original name for the Portfolio, an Atari-badged (almost) IBM PC
compatible hand-held computer.
Font
A particular instance of a typeface in a particular style and size, such as a
12 point Times italic font. In computing this definition tends to be relaxed
and can mean any character set of the same general design for display on
screen or printer including all its derivatives of style and size, in other
words it is confused with 'typeface'.
FONTGDOS
FONT Graphic Device Operating System. An updated version of GDOS with some
extra features such as b‚zier curve support, font caching and faster printer
drivers. It is essentially the same as FSMGDOS but without the font scaling
routines, therefore only being capable of handling bitmapped fonts. It
requires the EXTEND.SYS file used by FSMGDOS but takes the FSMCACHE value as
the value for a miscellaneous cache for itself for internal buffers and data
structures (using all of it towards the cache as opposed to just a
percentage). The second FSMCACHE value is ignored. The printer drivers are
faster than the older GDOS ones. The FONTGDOS.PRG file must be placed in the
AUTO folder as with the GDOS set up and the ASSIGN.SYS and EXTEND.SYS files
placed in the root directory. Three accessories which also come in CPX module
form are also supplied which help construct the ASSIGN.SYS and EXTEND.SYS
files. FONTGDOS.ACC allows the ASSIGN.SYS file to be altered, selecting the
bitmapped fonts, drivers and print quality. FSM.ACC allows the cache sizes in
EXTEND.SYS to be changed, and FSMPRINT.ACC is used to change the parameters of
the printer, such as paper size, quality and colours. FONTGDOS was issued
almost as an apology for the continued delays with FSMGDOS in early 1992. To
the programmer and user, it is essentially to be used the same as GDOS 1.1
except for the b‚zier curve features and the advantages of the caches. Tests
have shown it to be better behaved and faster than GDOS 1.1 and compatible
with GDOS software. See FSMGDOS, GDOS, SpeedoGDOS, ASSIGN.SYS, EXTEND.SYS,
Outline fonts.
Foreground
A program in a multiprogramming environment that takes priority over other
programs.
ForemNet
See FNet.
Form
To a programmer, a graphic object containing one or more other objects, such
as text, boxes, buttons, images and icons, for instance a GEM dialog box. Some
forms are very sophisticated, such as the whole Desktop in NeoDesk.
Formal parameter
A value entered in a program to establish the type, size or structure of an
item of data that will be inserted during compilation or at run time.
Format
The initialization of a disk ready for use, physically removing all previous
data. The process consists of checking each track for defects and writing
identifying and control data to each track and sector for access purposes. The
correct term for such a procedure is 'initialize', where formatting was only
one part of it. In micros, at least, the term formatting has taken over to
mean all the operations of disk initialization.
A ST double density disk formatted to the normal Desktop standard has 80
concentric tracks with track 0 on the outside and track 79 nearest the centre.
Each track is divided into nine sectors, numbered 1 to 9. On a single-sided
disk the tracks and sectors are arranged as follows:
Track 0, Sector 1 Boot Sector
Track 0, Sector 2-6 FAT 1
Track 0, Sector 7-Track 1, Sector 2 FAT 2
Track 1, Sector 3-9 Directory
Track 2-Track 79 File data
A double-sided disk has 80 tracks with nine sectors per track on each side of
the disk and is arranged as follows:
Side A, Track 0, Sector 1 Boot Sector
Side A, Track 0, Sector 2-6 FAT 1
Side A, Track 0, Sector 7-9 and
Side B, Track 0, Sector 1-2 FAT 2
Side B, Track 0, Sector 3-9 Directory
Side A and B, Track 1-Track 79 File data
Each sector holds a maximum of 512 bytes of data and sectors are arranged in
clusters which are the smallest storage units, which is two sectors. Only one
file may be allocated a cluster, so that if a file does not fill the whole
1,024 bytes of a cluster, the excess remains empty and unusable. For instance,
ten Degas fill pattern files, normally 64 bytes each, would occupy 10,240
bytes on a disk rather than 640 bytes! Larger files are obviously stored more
efficiently but the last cluster of any file will always be partly empty and
unused.
Nonstandard disk formats are common on the ST, where an increase in the number
of tracks or sectors per track is achieved. Using ten sectors per track is
generally safe and portable between computers, going beyond that (fourteen has
been tried) is generally not recommended because the quality of disk drives
and disks varies so much. The same applies to sectors. Up to 86 sectors per
track has been tried but generally a mechanical stop in the drive unit itself
normally prevents the read/write heads from going too far towards the centre
of the disk. Using software to move the head too far inwards will result in
rather unpleasant noises coming from the disk drive and can force the heads
out of alignment. Again, one or two extra sectors may be acceptable, any more
is definitely not recommended.
A high density floppy disk has twice the number of sectors per track as a
double density disk. In order to achieve this, the FDC clock signal needs to
be twice the normal rate, at 16 MHz.
At the time of format the disk can be given a volume name which has the same
form as a file name and stored on the disk. This can help to identify a disk's
contents.
Also, the term is used to describe the physical organization of data within a
file or on screen, such as arranging the text layout to conform to left and
right margin settings and justification. See Boot Sector, Cluster, Directory
sectors, FAT, Interleave, Sectors, Tracks.
Formatter
An operating system routine or utility program that enables the formatting of
disks usually with options to extend the disk's 'normal' capacity and/or
access speed.
Form Feed
See FF.
FORTH
A high-level language designed for real-time control applications.
FORTRAN
FORmula TRANslation. The first high-level language designed for mathematical
and scientific applications by IBM and released in 1957.
Forty folder bug
TOS allows for 80 blocks of RAM buffer in its system 'OS Pool'. Whenever a
folder is 'active' TOS creates and uses two of these blocks to store its
directory structure contents. An active folder is one which is the root
directory of the device it's on, or which has open files, or which is the
current directory of one or more processes for that drive, or which has an
'active' subdirectory. Each process has a current directory on every logical
drive. In addition, one block is used per open file and one quarter block is
used per memory chunk (allocated or free) in the system TPA. When files are
closed, processes terminated, or memory chunks are freed these blocks are
given back to the OS pool.
However, for TOS 1.0 and 1.2 'active' meant 'seen'. Getting a list of the
files in a directory causes all the folders there to take up blocks of the OS
pool regardless of whether they are opened or not. In addition, blocks never
get freed in the pool. Also, once blocks have been used for managing TPA
memory chunks, they were unavailable for managing folders, and vice versa.
Eventually - and quickly with a hard disk - the OS pool runs out and
unpredictable and serious problems can occur which normally ends with out of
memory errors and a system crash. TOS 1.4 lifts these restrictions and so
fixes this particular 40 folder bug. There are still limits, the 80 block OS
pool can still run out but this is unlikely except under extreme circumstances
of having an inordinate number and depth of folders and open files. The Atari
FOLDRXXX program was released to add memory to the OS pool. Naming it
FOLDR100.PRG and placing it in the AUTO folder gives the OS pool another 200
blocks, room for 100 additional active folders. This can still be used with
TOS 1.4 and later if a user does have deeply structured directories and gets
the "Out of Internal Memory" error.
Closely associated with this 40 folder problem are the bugs in the GEMDOS
Malloc() function which is used to allocate memory blocks to a program. The
version of Malloc() in TOS 1.0 and 1.2 had a limit of 20 allocated blocks per
process and attempting to allocate more would crash the system. Again,
FOLDRXXX would help alleviate this problem as Malloc() uses the OS pool.
However, another bug was introduced in TOS 1.4. Many programmers have been
relying on the fact that Malloc() in TOS 1.0 and 1.2 used to allocate two
blocks of memory contiguously in memory. As so many programs relied on this,
the new Malloc() function had to accommodate this behaviour. The bug was
introduced into the routine that coalesces contiguous memory blocks into one
free memory block. A patch program called POOLFIX.PRG is used to frequently
coalesce free memory blocks so that the bugged routine never executes.
Unfortunately, POOLFIX and POOLFIX2 are bugged and should not be used.
POOLFIX3 is the official Atari patch program which should be run from the AUTO
folder. POOLFIX4 was introduced by Claus Brod in Germany to fix a problem
POOLFIX3 had with some hard disks.
On systems that install a cookie jar, the _OOL Cookie shows that the POOLFIX
TOS patch program is installed.
Forward channel
A message channel, a communications channel used to carry data in an
asymmetric duplex system.
Fount
See Font.
FPATCH2.PRG
An official freeware Atari patch program that fixes two problems in the Falcon
BIOS in TOS 4.00-4.04. Sound is not initialized properly and the Bconmap()
function doesn't work. This patch supersedes FPATCH1.PRG which worked by
hooking into the BIOS trap and intercepting all the Bconxxx() function calls.
Version 2 fixes the Bconmap() problem directly by setting the Bconmap() table
size to its correct value and hence requires no resident code. It also has the
benefit of allowing the Falcon LAN port to be accessed via the BIOS. It should
be run from the AUTO folder.
FPU
Floating Point processor Unit. An integrated circuit device designed to
perform floating point mathematical calculations at optimum speed and
relieving the CPU from those tasks. This chip is often a coprocessor to the
main CPU but in the latest CPU's, such as the MC68040 and the Intel 80486, the
coprocessor is integrated into the main chip architecture. However, the
processor, as with any FPU, will only speed up the mathematical operations of
programs that are specifically written to use it, of which there are very few
on the ST-Falcon even though most C compilers have floating point routine
libraries. The Mega ST and Mega STE can both support MC68881 FPUs and the TT
and Falcon030 support a MC68882 FPU in coprocessor mode. See SFP004, MC68881,
MC88882.
Fragmentation
The state of a disk when files do not occupy contiguous sectors on its
surface. When files are deleted from a disk their sectors become available to
other files which may need more than these sectors for storage. The other
sectors are found elsewhere on the disk making them non-contiguous across the
disk surface. With increasing deletion and copying this fragmentation of the
newer files gets worse. Consequently, it takes longer for the disk's
read/write heads to read the data from all these scattered tracks and it takes
longer to find empty sectors to write data to, thus making all disk operations
slower. Some programs can defragment a disk but because of the way they work,
a disk backup is always recommended beforehand. A full disk backup, zeroing
the disks and copying the files back again will defragment a disk.
Frame
A term used to describe the 'box' within which text or graphic images are
placed in WIMP environment DTP and graphic processing programs. Such frames
are usually moveable and re-sizable by use of handles and if so, are often
called rubber boxes.
Frame rate
The refresh rate.
Framing
Using beginning and ending delimiters around data items to distinguish one
item from another, especially in a stream of such items.
Framing bits
Start and stop bits.
Free space
The available memory on disk or RAM for use.
Free standing
A functional unit contained within its own case and not enclosed within the
main system. Also, an intelligent terminal in a network.
Freeware
Programs that are freely available and generally distributed by PD libraries
and bulletin board networks but to which the programmer keeps all rights. The
usage fee may be free or voluntary, the user being under no obligation to pay
as with shareware. Freeware programs are not public domain, the copyright is
still retained by the programmer and they cannot be sold for profit. See
Public domain, Shareware.
Frequency
The number of times per second that a sequence of conditions is repeated, such
as waves of sound or current. The unit of measurement is a Hertz (Hz).
Frequency modulation
In communications and a system using a carrier wave, the method of modulation
in which the frequency of the carrier wave is changed in an analogue manner to
transmit speech or data. Also, a method of data recording onto magnetizable
surfaces in which the direction of current in the coil of the read/write head
(and hence the direction of orientation of the magnetizable articles) is
changed at intervals established by a clock sequence. The direction is changed
at the midpoint of an interval to write a 1-bit and left unchanged for a 0-
bit.
Frequency-shift keying
A method of data transmission in which a carrier wave is modulated at only a
limited number of frequencies, each of which represents a bit or an
established group of bits, such as a dibit. It is normally used for low-speed
transmissions, such as 300 bps.
Friction feed
A printer that does not use sprockets to move the paper but relies on the
friction of the platen against the paper to move it.
Front end
The user input/output interface program between the user and the operating
system, such as the GEM Desktop and the MS-DOS command line.
FSFMV
Full-Screen, Full-Motion Video. A term used to describe the attributes of some
CD-ROM systems which can display a moving picture the same size as the display
device being used.
FSMGDOS
Font Scaling Module Graphic Device Operating System. A replacement for GDOS
allowing use of scalable outline fonts as well as GDOS bitmapped ones. FSMGDOS
generates character bitmaps of any point size for devices of any resolution
with independent height and width settings for compressed and expanded font
styles. Output can be mirrored on the X and Y axis as well as rotated and
skewed. Font caching for bitmapped fonts is an important feature enabling only
the fonts currently in use to be loaded into memory. As long as the memory
size of the BITCACHE, which can be specified by the user, is larger than the
biggest font, FSMGDOS will be able to use as many bitmap fonts as the user
wishes in a limited memory space. Another cache for the scalable outline fonts
is also provided. This cache, FSMCACHE, holds the actual character data when a
character is requested and FSMGDOS builds the bitmap from the font data. This
first generation of any character will be slow so the bitmap is retained in
memory for later use so that each character doesn't have to be generated every
time. These caches can be saved to disk. A third cache (second FSMCACHE
parameter) is used for internal buffers and data structures and its size
depends on how many fonts are used and their point sizes.
Support for b‚zier curves and pair or track kerning control is present.
FSMGDOS should be compatible with all programs using GDOS. An install program
should make installation of FSMGDOS easy and three accessories are provided
(also in CPX module format) to alter this configuration. FSM Font Manager
allows the configuration of the fonts, which ones to use and their sizes. It
also allows manipulation of the FSM caches and creation of width tables. The
FSM Printer Configuration accessory is used to change the printer driver
configuration including the page size, quality and number of colours. The last
accessory, GDOS Printer Selector, is used to manage the old bitmaps fonts and
effectively manipulates the ASSIGN.SYS file.
Although developer's versions abound with regular updates, consistent problems
have caused great delays with promises of its appearance for several years.
FSMGDOS was to be available at the end of 1992 but was replaced by SpeedoGDOS
using the scaling technology of the Bitstream Speedo Font Scaler. See GDOS,
FONTGDOS, SpeedoGDOS, ASSIGN.SYS, EXTEND.SYS, Outline font.
FTP
File Transfer Protocol. A protocol for transferring files under TCP/IP across
the Internet. Also, the name of the program itself, usually UNIX-based.
Fuji
The Atari icon formed by Atari characters 14 and 15, being a representation of
Mount Fuji in Japan and the company's trademark.
Full box
The icon in the top right-hand corner of a GEM window which, when clicked on,
will open the window to the maximum size of the screen and when clicked on
again, back to the previous size. It is sometimes referred to as the Zoom box.
Fulling
The act of clicking on the Full box and making the GEM window take on the size
of the whole screen.
Function
That which is done or performed. Also, a sequence of instructions provided to
accomplish a particular operation and providing a single result or output for
any input arguments and is invoked by making a call to its name supplying the
arguments. Sometimes called a routine. Also, an expression.
Function key
A special key on a keyboard [F1]-[F10] assigned a program independent
operation. Although there is a de facto standard for their use on the PC
compatibles, i.e. [F1] provides Help, there is no such standard on the ST-
Falcon range. NewDesk allows them to be used to launch programs.
Functional unit
An item of hardware which performs some function within a computer system,
such as a modem, printer, disk drive or the computer itself.
FUNNEL
An Atari ASIC chip for the TT. ST RAM on the TT is 64 bits wide and as the
68030 has only a 32-bit width, the FUNNEL interleaves the 64 bits down to 32
bits for the 68030 and the sixteen bits required for the sound and elsewhere.
See ST RAM.
Fuse
A current-limiting device that protects a circuit from excessive current flow
by melting, thus breaking a circuit and stopping that current.
FWIW
For What It's Worth. Commonly used shorthand in e-mail and other messages.
FYI
For Your Information. Commonly used shorthand in e-mail and other messages.
F
115 entries
EOF