ATC(6) BSD Games Manual ATC(6)
atc -- air traffic controller game
atc [-lpqstu?] [-f game] [-g game] [-r seed]
atc lets you try your hand at the nerve-wracking duties of an air traffic
controller without endangering the lives of millions of travelers each
year. Your responsibilities require you to direct the flight of jets and
prop planes into and out of the flight arena and airports. The speed
(update time) and frequency of the planes depend on the difficulty of the
-f game Play the named game. If the game listed is not one of the ones
printed by the -l option, the default game is played.
-g game Same as -f.
-l Print a list of available games and exit. The first game name
printed is the default game.
-p Print the path to the special directory where atc expects to
find its private files. This is used during the installation
of the program.
-q Play quietly (no bells).
-r seed Set the random seed. This option can be used to replay a spe-
-s Print the score list (formerly the Top Ten list). The scoring
information is the game time in ``radar updates'', the wall-
clock game time, and the number of planes that were success-
fully dealt with.
-t Same as -s.
-u Print the usage line and exit.
-? Same as -u.
Your goal in atc is to keep the game going as long as possible. There is
no winning state, except to beat the times of other players. You will
need to: launch planes at airports (by instructing them to increase their
altitude); land planes at airports (by instructing them to go to altitude
zero when exactly over the airport); and maneuver planes out of exit
Several things will cause the end of the game. Each plane has a destina-
tion (see information area), and sending a plane to the wrong destination
is an error. Planes can run out of fuel, or can collide. Collision is
defined as adjacency, horizontal or vertical. A plane leaving the arena
in any other way than through its correct destination exit is an error as
Scores are sorted in order of the number of planes safe. The other sta-
tistics are provided merely for fun. There is no penalty for taking
longer than another player (except in the case of ties).
Suspending a game is not permitted. If you get a talk message, tough.
When was the last time an Air Traffic Controller got called away to the
Depending on the terminal used, the atc screen will be divided into 4
areas. It should be stressed that the terminal driver portion of the
game was designed to be reconfigurable, so the display format can vary
depending on the version you are playing. The descriptions here are
based on the ASCII version of the game. The game rules and input format,
however, should remain consistent. Control-L redraws the screen, should
it become muddled.
The first screen area is the radar display, showing the relative loca-
tions of the planes, airports, standard entry/exit points, radar beacons,
and ``lines'' which simply serve to aid you in guiding the planes.
Planes are shown as a single letter with an altitude. If the numerical
altitude is a single digit, then it represents thousands of feet. Some
distinction is made between the prop planes and the jets. On ASCII ter-
minals, prop planes are represented by an upper case letter, jets by a
lower case letter.
Airports are shown as a number and some indication of the direction
planes must be going to land at the airport. On ASCII terminals, this is
one of '^', '>', '<', or 'v', to indicate north (0 degrees), east (90),
west (270), and south (180), respectively. The planes will also take off
in this direction.
Beacons are represented as circles or asterisks and a number. Their pur-
pose is to offer a place of easy reference to the plane pilots. See The
Delay Command under the input section of this manual.
Entry/exit points are displayed as numbers along the border of the radar
screen. Planes will enter the arena from these points without warning.
These points have a direction associated with them, and planes will
always enter the arena from this direction. On the ASCII version of atc,
this direction is not displayed. It will become apparent what this
direction is as the game progresses.
Incoming planes will always enter at the same altitude: 7000 feet. For a
plane to depart successfully through an entry/exit point, it must be fly-
ing at 9000 feet. It is not necessary for the planes to be flying in any
particular direction when they leave the arena (yet).
The second area of the display is the information area, which lists the
time (number of updates since start) and the number of planes you have
directed safely out of the arena. Below this is a list of planes cur-
rently in the air, followed by a blank line, and then a list of planes on
the ground (at airports). Each line lists the plane name and its current
altitude, an optional asterisk indicating low fuel, the plane's destina-
tion, and the plane's current command. Changing altitude is not consid-
ered to be a command and is therefore not displayed. The following are
some possible information lines:
B4*A0: Circle @ b1
g7 E4: 225
The first example shows a prop plane named 'B' that is flying at 4000
feet. It is low on fuel (note the '*'). Its destination is Airport #0.
The next command it expects to do is circle when it reaches Beacon #1.
The second example shows a jet named 'g' at 7000 feet, destined for Exit
#4. It is just now executing a turn to 225 degrees (Southwest).
The third area of the display is the input area. It is here that your
input is reflected. See the INPUT heading of this manual for more
This area is used simply to give credit where credit is due. :-)
A command completion interface is built into the game. At any time, typ-
ing '?' will list possible input characters. Typing a backspace (your
erase character) backs up, erasing the last part of the command. When a
command is complete, a return enters it, and any semantic checking is
done at that time. If no errors are detected, the command is sent to the
appropriate plane. If an error is discovered during the check, the
offending statement will be underscored and a (somewhat) descriptive mes-
sage will be printed under it.
The command syntax is broken into two parts: Immediate Only and Delayable
commands. Immediate Only commands happen on the next update. Delayable
commands also happen on the next update unless they are followed by an
optional predicate called the Delay command.
In the following tables, the syntax [0-9] means any single digit, and
<dir> refers to the keys around the 's' key, namely ``wedcxzaq''. In
absolute references, 'q' refers to Northwest or 315 degrees, and 'w'
refers to North, or 0 degrees. In relative references, 'q' refers to -45
degrees or 45 degrees left, and 'w' refers to 0 degrees, or no change in
All commands start with a plane letter. This indicates the recipient of
the command. Case is ignored.
IMMEDIATE ONLY COMMANDS
a [ cd+- ] number
Altitude: Affect a plane's altitude, possibly requesting takeoff.
'+' and '-' are the same as 'c' and 'd'.
a [0-9] Go to the given altitude (thousands of feet).
c [0-9] Climb: Relative altitude change (thousands of feet).
d [0-9] Descend: Relative altitude change (thousands of feet).
m Mark: Display in highlighted mode. Plane and command information
is displayed normally.
i Ignore: Do not display highlighted. Command information is dis-
played as a line of dashes if there is no command.
u Unmark: Same as ignore, but if a delayed command is processed, the
plane will become marked. This is useful if you want to forget
about a plane during part, but not all, of its journey.
c Circle: Have the plane circle.
t [ l-r+LR ] [ dir ] or tt [ abe* ] number
Turn: Change direction.
t<<dir>> Turn to the absolute compass heading given. The short-
est turn will be taken.
tl Left: Turn counterclockwise (45 degrees by default).
tl <<dir>> Turn ccw the given number of degrees. Zero
degrees ('w') is no turn; 45 degrees ccw is
'e'. The shortest turn will be taken; for
instance, if you specify a ccw turn of 315
degrees ('q'), which should take several
turns, the plane will really turn 45 cw,
which takes only one turn.
tr Right: Turn clockwise (45 degrees by default).
tr <<dir>> Analogous to turn left <dir>.
tL Turn counterclockwise 90 degrees.
tR Turn clockwise 90 degrees.
tt [abe*] Towards: Turn towards a beacon, airport or exit. The
turn is just an estimate.
ttb number Turn towards the specified beacon.
tt* number Equivalent to ttb.
tte number Turn towards the specified exit.
tta number Turn towards the specified airport.
THE DELAY COMMAND
The Delay (a/@) command may be appended to any Delayable command. It
allows the controller to instruct a plane to do an action when the plane
reaches a particular beacon (or other objects in future versions).
a/@ At: Do the given delayable command when the plane reaches
the given beacon.
ab number The letter is redundant to allow for expansion.
'@' can be used instead of 'a'.
MARKING, UNMARKING AND IGNORING
Planes are marked by default when they enter the arena. This means they
are displayed in highlighted mode on the radar display. A plane may also
be either unmarked or ignored. An unmarked plane is drawn in unhigh-
lighted mode, and a line of dashes is displayed in the command field of
the information area. The plane will remain this way until a mark com-
mand has been issued. Any other command will be issued, but the command
line will return to a line of dashes when the command is completed.
An ignored plane is treated the same as an unmarked plane, except that it
will automatically switch to marked status when a delayed command has
been processed. This is useful if you want to forget about a plane for a
while, but its flight path has not yet been completely set.
As with all of the commands, marking, unmarking and ignoring will take
effect at the beginning of the next update. Do not be surprised if the
plane does not immediately switch to unhighlighted mode.
atlab1 Plane A: turn left at beacon #1
cc Plane C: circle
gtte4ab2 Plane G: turn towards exit #4 at beacon #2
ma+2 Plane M: altitude: climb 2000 feet
stq Plane S: turn to 315
xi Plane X: ignore
o Jets move every update; prop planes move every other update.
o All planes turn at most 90 degrees per movement.
o Planes enter at 7000 feet and leave at 9000 feet.
o Planes flying at an altitude of 0 crash if they are not over an air-
o Planes waiting at airports can only be told to take off (climb in
o Pressing return (that is, entering an empty command) will perform the
next update immediately. This allows the player to ``fast forward''
the game clock if nothing interesting is happening.
The Game_List file lists the currently available play fields. New field
description file names must be placed in this file to be playable. If a
player specifies a game not in this file, his score will not be logged.
The game field description files are broken into two parts. The first
part is the definition section. Here, the four tunable game parameters
must be set. These variables are set with the syntax:
variable = number;
Variable may be one of: update, indicating the number of seconds between
forced updates; newplane, indicating (about) the number of updates
between new plane entries; width, indicating the width of the play field;
or height, indicating the height of the play field.
The second part of the field description files describes the locations of
the exits, the beacons, the airports and the lines. The syntax is as
beacon: (x y) ... ;
airport: (x y direction) ... ;
exit: (x y direction) ... ;
line: [ (x1 y1) (x2 y2) ] ... ;
For beacons, a simple x, y coordinate pair is used (enclosed in
parentheses). Airports and exits require a third value, a direction,
which is one of ``wedcxzaq''. For airports, this is the direction that
planes must be going to take off and land, and for exits, this is the
direction that planes will be going when they enter the arena. This may
not seem intuitive, but as there is no restriction on direction of exit,
this is appropriate. Lines are slightly different, since they need two
coordinate pairs to specify the line endpoints. These endpoints must be
enclosed in square brackets.
All statements are semi-colon (;) terminated. Multiple item statements
accumulate. Each definition must occur exactly once, before any item
statements. Comments begin with a hash (#) symbol and terminate with a
newline. The coordinates are between zero and width-1 and height-1
inclusive. All of the exit coordinates must lie on the borders, and all
of the beacons and airports must lie inside of the borders. Line end-
points may be anywhere within the field, so long as the lines are hori-
zontal, vertical or exactly diagonal.
FIELD FILE EXAMPLE
# This is the default game.
update = 5;
newplane = 5;
width = 30;
height = 21;
exit: ( 12 0 x ) ( 29 0 z ) ( 29 7 a ) ( 29 17 a )
( 9 20 e ) ( 0 13 d ) ( 0 7 d ) ( 0 0 c ) ;
beacon: ( 12 7 ) ( 12 17 ) ;
airport: ( 20 15 w ) ( 20 18 d ) ;
line: [ ( 1 1 ) ( 6 6 ) ]
[ ( 12 1 ) ( 12 6 ) ]
[ ( 13 7 ) ( 28 7 ) ]
[ ( 28 1 ) ( 13 16 ) ]
[ ( 1 13 ) ( 11 13 ) ]
[ ( 12 8 ) ( 12 16 ) ]
[ ( 11 18 ) ( 10 19 ) ]
[ ( 13 17 ) ( 28 17 ) ]
[ ( 1 7 ) ( 11 7 ) ] ;
Files are kept in a special directory, which can be shown by using the -p
/var/games/atc_score Score file.
/usr/share/games/atc/Game_List The list of playable games.
Ed James, UC Berkeley: firstname.lastname@example.org, ucbvax!edjames
This game is based on someone's description of the overall flavor of a
game written for some unknown PC many years ago, maybe.
The screen sometimes refreshes after you have quit.
BSD November 30, 2014 BSD