ATC(6) BSD Games Manual ATC(6)
atc -- air traffic controller game
atc [-u?lstp] [-gf game name] [-r random seed]
atc lets you try your hand at the nerve wracking duties of the air traffic controller with-
out 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 air-
ports. The speed (update time) and frequency of the planes depend on the difficulty of the
-u Print the usage line and exit.
-? Same as -u.
-l Print a list of available games and exit. The first game name printed is the default
-s Print the score list (formerly the Top Ten list).
-t Same as -s.
-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.
Play the named game. If the game listed is not one of the ones printed from the -l
option, the default game is played.
Same as -g.
Set the random seed. The purpose of this flag is questionable.
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 destination (see informa-
tion 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 in all three dimensions. A plane
leaving the arena in any other way than through its destination exit is an error as well.
Scores are sorted in order of the number of planes safe. The other statistics 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 phone?
Depending on the terminal you run atc on, the screen will be divided into 4 areas. It
should be stressed that the terminal driver portion of the game was designed to be reconfig-
urable, 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 for-
mat, however, should remain consistent. Control-L redraws the screen, should it become mud-
The first screen area is the radar display, showing the relative locations 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 terminals, prop planes are represented by a upper case let-
ter, 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 `^', `>', `<', and `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 purpose is to offer a
place of easy reference to the plane pilots. See THE DELAY COMMAND section below.
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 asso-
ciated 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 direc-
tion is as the game progresses.
Incoming planes will always enter at the same altitude: 7000 feet. For a plane to success-
fully depart through an entry/exit point, it must be flying at 9000 feet. It is not neces-
sary for the planes to be flying in any particular direction when they leave the arena
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 currently 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 destination, and the plane's
current command. Changing altitude is not considered 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 (South-West).
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 details.
This area is used simply to give credit where credit is due. :-)
A command completion interface is built into the game. At any time, typing `?' 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 appro-
priate plane. If an error is discovered during the check, the offending statement will be
underscored and a (hopefully) descriptive message 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 a
direction, given by the keys around the `s' key: ``wedcxzaq''. In absolute references, `q'
refers to North-West 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 direction.
All commands start with a plane letter. This indicates the recipient of the command. Case
IMMEDIATE ONLY COMMANDS
a [ cd+- ] number
Altitude: Change a plane's altitude, possibly requesting takeoff. `+' and `-' are the
same as `c' and `d'.
a number Climb or descend to the given altitude (in thousands of feet).
ac number Climb: relative altitude change.
ad number Descend: relative altitude change.
m Mark: Display in highlighted mode. Plane and command information is displayed nor-
i Ignore: Do not display highlighted. Command is displayed 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 [ lr ]
Circle: Have the plane circle.
cl Left: Circle counterclockwise.
cr Right: Circle clockwise (default).
t [ l-r+LR ] [ dir ] or tt [ abe* ] number
Turn: Change direction.
t<dir> Turn to direction: Turn to the absolute compass heading given. The short-
est turn will be taken.
tl [ dir ] Left: Turn counterclockwise: 45 degrees by default, or the amount speci-
fied in <dir> (not to <dir>.) `w' (0 degrees) is no turn. `e' is 45
degrees; `q' gives -45 degrees counterclockwise, that is, 45 degrees
t- [ dir ] Same as left.
tr [ dir ] Right: Turn clockwise, 45 degrees by default, or the amount specified in
t+ [ dir ] Same as right.
tL Hard left: Turn counterclockwise 90 degrees.
tR Hard right: Turn clockwise 90 degrees.
tt [abe*] Towards: Turn towards a beacon, airport or exit. The turn is just an
tta number Turn towards the given airport.
ttb number Turn towards the specified beacon.
tte number Turn towards an exit.
tt* number Same as ttb.
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).
Do the delayable command when the plane reaches the specified beacon. The `b' for
``beacon'' 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
ignored plane is drawn in unhighlighted mode, and a line of dashes is displayed in the com-
mand field of the information area. The plane will remain this way until a mark command 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 unmarked plane is treated the same as an ignored 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
As with all of the commands, marking, unmarking and ignoring will take effect at the begin-
ning of the next update. Do not be surprised if the plane does not immediately switch to
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 airport.
o Planes waiting at airports can only be told to take off (climb in altitude).
o Pressing return (that is, entering an empty command) will perform the next update imme-
diately. This allows you to ``fast forward'' the game clock if nothing interesting is
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 defini-
tion 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, indi-
cating 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 follows:
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 parenthesis). Airports and
exits require a third value, which is one of the directions 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 endpoints may be anywhere within
the field, so long as the lines are horizontal, 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. See the OPTIONS section for a way to print this path
out. It is normally /usr/share/games/atc.
This directory contains the file Game_List, which holds the list of playable games, as well
as the games themselves.
The scores are kept in /var/games/atc_score.
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 January 1, 2004 BSD