— air traffic
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 chosen arena.
- Play the named game. If
the game listed is not one of the ones printed by the
-l option, the default game is played.
- Same as -f.
- Print a list of available games and exit. The first game
name printed is the default game.
- 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 quietly (no bells).
- Set the random seed. This option can be used to replay a
- 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 successfully
- Same as -s.
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
Several things will cause the end of the game. Each plane has a destination (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 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 used, the atc
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
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 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 purpose is
to offer a place of easy reference to the plane pilots. See
The Delay Command
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 flying 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 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
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
The third area of the display is the input area. It is here that your input is
reflected. See the INPUT
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 appropriate
plane. If an error is discovered during the check, the offending statement
will be underscored and a (somewhat) descriptive message will be printed under
The command syntax is broken into two parts: Immediate
commands happen on the next
commands also happen on the
next update unless they are followed by an optional predicate called the
In the following tables, the syntax [0-9]
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 direction.
All commands start with a plane letter. This indicates the recipient of the
command. Case is ignored.
- a [
cd+- ] number
- Altitude: Affect a plane's altitude, possibly requesting
takeoff. ‘+’ and ‘-’ are the same as
‘c’ and ‘d’.
- Go to the given altitude (thousands of feet).
- Climb: Relative altitude change (thousands of
- Descend: Relative altitude change (thousands of
- Mark: Display in highlighted mode. Plane and command
information is displayed normally.
- Ignore: Do not display highlighted. Command information is
displayed as a line of dashes if there is no command.
- 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.
- Circle: Have the plane circle.
- t [
l-r+LR ] [ dir ] or tt
[ abe* ] number
- Turn: Change direction.
- Turn to the absolute compass heading given. The
shortest turn will be taken.
- Left: Turn counterclockwise (45 degrees by default).
- 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
- Right: Turn clockwise (45 degrees by default).
- Analogous to turn left <dir>.
- Turn counterclockwise 90 degrees.
- Turn clockwise 90 degrees.
- Towards: Turn towards a beacon, airport or exit. The
turn is just an estimate.
- Turn towards the specified beacon.
- Equivalent to
- Turn towards the specified exit.
- Turn towards the specified airport.
(a/@) command may be appended to any
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).
- At: Do the given delayable command when the plane reaches
the given beacon.
- The letter is redundant to allow for expansion.
‘@’ can be used instead of ‘a’.
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
. An unmarked
plane is drawn in unhighlighted 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 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.
plane is treated the same as an unmarked
plane, except that it will automatically switch to
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.
- Plane A: turn left at beacon #1
- Plane C: circle
- Plane G: turn towards exit #4 at beacon #2
- Plane M: altitude: climb 2000 feet
- Plane S: turn to 315
- Plane X: ignore
- Jets move every update; prop planes move every other
- All planes turn at most 90 degrees per movement.
- Planes enter at 7000 feet and leave at 9000 feet.
- Planes flying at an altitude of 0 crash if they are not
over an airport.
- Planes waiting at airports can only be told to take off
(climb in altitude).
- 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
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
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:
, indicating the number of
seconds between forced updates;
(about) the number of updates between new plane entries;
, indicating the width of the play field; or
, 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:
- (x y) ... ;
- (x y direction) ... ;
- (x y direction) ... ;
- [ (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 endpoints may be anywhere
within the field, so long as the lines are horizontal, vertical or
# 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 ) ] ;
- Name to be recorded in high score file.
Files are kept in a special directory, which can be shown by using the
- Score file.
- The list of playable games.
, UC Berkeley:
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.