SAIL(6) BSD SAIL(6)
NAME
sail - multi-user wooden ships and iron men
SYNOPSIS
sail [ -s [ -l ] ] [ -x ] [ -b ] [ num ]
DESCRIPTION
sail is a computer version of Avalon Hill's game of fighting sail
originally developed by S. Craig Taylor.
Players of sail take command of an old fashioned Man of War and fight
other players or the computer. They may re-enact one of the many
historical sea battles recorded in the game, or they can choose a
fictional battle.
As a sea captain in the sail Navy, the player has complete control over
the workings of his ship. He must order every maneuver, change the set
of his sails, and judge the right moment to let loose the terrible
destruction of his broadsides. In addition to fighting the enemy, he
must harness the powers of the wind and sea to make them work for him.
The outcome of many battles during the age of sail was decided by the
ability of one captain to hold the "weather gauge."
OPTIONS
-s Print the names and ships of the top ten sailors.
-l Show the login name. Only effective with -s.
-x Play the first available ship instead of prompting for a choice.
-b No bells.
HISTORICAL INFO
Old Square Riggers were very maneuverable ships capable of intricate
sailing. Their only disadvantage was an inability to sail very close to
the wind. The design of a wooden ship allowed only for the guns to bear
to the left and right sides. A few guns of small aspect (usually 6 or 9
pounders) could point forward, but their effect was small compared to a
68 gun broadside of 24 or 32 pounders. The guns bear approximately like
so:
\
b----------------
---0
\
\
\ up to a range of ten (for round shot)
\
\
\
An interesting phenomenon occurred when a broadside was fired down the
length of an enemy ship. The shot tended to bounce along the deck and
did several times more damage. This phenomenon was called a rake.
Because the bows of a ship are very strong and present a smaller target
than the stern, a stern rake (firing from the stern to the bow) causes
more damage than a bow rake.
b
00 ---- Stern rake!
a
Most ships were equipped with carronades, which were very large, close
range cannons. American ships from the revolution until the War of 1812
were almost entirely armed with carronades. The period of history
covered in sail runs approximately from the 1770's until the end of
Napoleonic France in 1815.
Fighting ships came in several sizes classed by armament. The mainstays
of any fleet were its "Ships of the Line", or "Line of Battle Ships".
They were so named because these ships fought together in great lines.
They were close enough for mutual support, yet every ship could fire both
its broadsides. We get the modern words "ocean liner," or "liner," and
"battleship" from "ship of the line." The most common size was the the
74 gun two decked ship of the line. The two gun decks usually mounted 18
and 24 pounder guns.
The pride of the fleet were the first rates. These were huge three
decked ships of the line mounting 80 to 136 guns. The guns in the three
tiers were usually 18, 24, and 32 pounders in that order from top to
bottom.
Various other ships came next. They were almost all "razees," or ships
of the line with one deck sawed off. They mounted 40-64 guns and were a
poor cross between a frigate and a line of battle ship. They neither had
the speed of the former nor the firepower of the latter.
Next came the "eyes of the fleet." Frigates came in many sizes mounting
anywhere from 32 to 44 guns. They were very handy vessels. They could
outsail anything bigger and outshoot anything smaller. Frigates didn't
fight in lines of battle as the much bigger 74's did. Instead, they
harassed the enemy's rear or captured crippled ships. They were much
more useful in missions away from the fleet, such as cutting out
expeditions or boat actions. They could hit hard and get away fast.
Lastly, there were the corvettes, sloops, and brigs. These were smaller
ships mounting typically fewer than 20 guns. A corvette was only
slightly smaller than a frigate, so one might have up to 30 guns. Sloops
were used for carrying dispatches or passengers. Brigs were something
you built for land-locked lakes.
SAIL PARTICULARS
Ships in sail are represented by two characters. One character
represents the bow of the ship, and the other represents the stern.
Ships have nationalities and numbers. The first ship of a nationality is
number 0, the second number 1, etc. Therefore, the first British ship in
a game would be printed as "b0". The second Brit would be "b1", and the
fifth Don would be "s4".
Ships can set normal sails, called Battle Sails, or bend on extra canvas
called Full Sails. A ship under full sail is a beautiful sight indeed,
and it can move much faster than a ship under Battle Sails. The only
trouble is, with full sails set, there is so much tension on sail and
rigging that a well aimed round shot can burst a sail into ribbons where
it would only cause a little hole in a loose sail. For this reason,
rigging damage is doubled on a ship with full sails set.
A ship with full sails set has a capital letter for its nationality. For
example, a French ship, normally "f0", with full sails set would be
printed as "F0".
When a ship is battered into a listing hulk, the last man aboard "strikes
the colors." This ceremony is the ship's formal surrender. The
nationality character of a surrendered ship is printed as "!". Thus, the
French ship of the last example would soon be "!0".
A ship has a random chance of catching fire or sinking when it reaches
the stage of listing hulk. A sinking ship has a tilde (~) printed for
its nationality, and a ship on fire and about to explode has a pound sign
(#) printed.
Captured ships become the nationality of the prize crew. Therefore, if
an American ship captures a British ship, the British ship will have an
"a" printed for its nationality. In addition, the ship number is changed
to "&","'", "(", ,")", "*", or "+" depending upon the original number, be
it 0,1,2,3,4, or 5. E.g., the "b0" captured by an American becomes the
"a&". The "s4" captured by the French becomes the "f*".
MOVEMENT
Movement is the most confusing part of sail to many. Ships can head in 8
directions:
0 0 0
b b b0 b b b 0b b
0 0 0
The stern of a ship moves when it turns. The bow remains stationary.
Ships can always turn, regardless of the wind (unless they are becalmed).
All ships drift when they lose headway. If a ship doesn't move forward
at all for two turns, it will begin to drift. If a ship has begun to
drift, then it must move forward before it turns, if it plans to do more
than make a right or left turn, which is always possible.
Movement commands to sail are a string of forward moves and turns. An
example is "l3". It will turn a ship left and then move it ahead 3
spaces. In the drawing above, the "b0" made 7 successive left turns.
When sail prompts you for a move, it prints three characters of import,
e.g.,
move (7, 4):
The first number is the maximum number of moves you can make, including
turns. The second number is the maximum number of turns you can make.
Between the numbers is sometimes printed a single quote ('). If the
quote is present, it means that your ship has been drifting, and you must
move ahead to regain headway before you turn (see note above). Some of
the possible moves for the example above are as follows:
move (7, 4): 7
move (7, 4): 1
move (7, 4): d /* drift, or do nothing */
move (7, 4): 6r
move (7, 4): 5r1
move (7, 4): l1r1r2
Because square riggers performed so poorly sailing into the wind, if at
any point in a movement command you turn into the wind, the movement
stops there:
move (7, 4): l1l4
Movement Error;
Helm: l1l
Moreover, whenever you make a turn, your movement allowance drops to the
lesser of a) what's left and b) what you would have at the new attitude.
In short, if you turn closer to the wind, you most likely won't be able
to sail the full allowance printed in the "move" prompt.
Old sailing captains had to keep an eye constantly on the wind. Captains
in sail are no different. A ship's ability to move depends on its
attitide to the wind. The best angle possible is to have the wind off
your quarter, that is, just off the stern. The direction rose on the
side of the screen gives the possible movements for your ship at all
positions to the wind. Battle sail speeds are given first, and full sail
speeds are given in parenthesis.
0 1(2)
\|/
-^-3(6)
/|\
| 4(7)
3(6)
Pretend the bow of your ship (the "^") is pointing upward and the wind is
blowing from the bottom to the top of the page. The numbers at the
bottom "3(6)" will be your speed under battle or full sails in such a
situation. If the wind is off your quarter, then you can move "4(7)".
If the wind is off your beam, "3(6)". If the wind is off your bow, then
you can only move "1(2)". Facing into the wind, you can't move at all.
Ships facing into the wind were said to be "in irons".
WINDSPEED AND DIRECTION
The windspeed and direction is displayed as a little weather vane on the
side of the screen. The number in the middle of the vane indicates the
wind speed, and the + to - indicates the wind direction. The wind blows
from the + sign (high pressure) to the - sign (low pressure). E.g.,
|
3
+
The wind speeds are 0 = becalmed, 1 = light breeze, 2 = moderate breeze,
3 = fresh breeze, 4 = strong breeze, 5 = gale, 6 = full gale, 7 =
hurricane. If a hurricane shows up, all ships are destroyed.
GRAPPLING AND FOULING
If two ships collide, they run the risk of becoming tangled together.
This is called "fouling." Fouled ships are stuck together, and neither
can move. They can unfoul each other if they want to. Boarding parties
can only be sent across to ships when the antagonists are either fouled
or grappled.
Ships can grapple each other by throwing grapnels into the rigging of the
other.
The number of fouls and grapples you have are displayed on the upper
right of the screen.
BOARDING
Boarding was a very costly venture in terms of human life. Boarding
parties may be formed in sail to either board an enemy ship or to defend
your own ship against attack. Men organized as Defensive Boarding
Parties fight twice as hard to save their ship as men left unorganized.
The boarding strength of a crew depends upon its quality and upon the
number of men sent.
CREW QUALITY
The British seaman was world renowned for his sailing abilities.
American sailors, however, were actually the best seamen in the world.
Because the American Navy offered twice the wages of the Royal Navy,
British seamen who liked the sea defected to America by the thousands.
In sail, crew quality is quantized into 5 energy levels. "Elite" crews
can outshoot and outfight all other sailors. "Crack" crews are next.
"Mundane" crews are average, and "Green" and "Mutinous" crews are below
average. A good rule of thumb is that "Crack" or "Elite" crews get one
extra hit per broadside compared to "Mundane" crews. Don't expect too
much from "Green" crews.
BROADSIDES
Your two broadsides may be loaded with four kinds of shot: grape, chain,
round, and double. You have guns and carronades in both the port and
starboard batteries. Carronades only have a range of two, so you have to
get in close to be able to fire them. You have the choice of firing at
the hull or rigging of another ship. If the range of the ship is greater
than 6, then you may only shoot at the rigging.
The types of shot and their advantages are:
Round Range of 10. Good for hull or rigging hits.
Double Range of 1. Extra good for hull or rigging hits. Double takes
two turns to load.
Chain Range of 3. Excellent for tearing down rigging. Cannot damage
hull or guns, though.
Grape Range of 1. Sometimes devastating against enemy crews.
On the side of the screen is displayed some vital information about your
ship:
Load D! R!
Hull 9
Crew 4 4 2
Guns 4 4
Carr 2 2
Rigg 5 5 5 5
"Load" shows what your port (left) and starboard (right) broadsides are
loaded with. A "!" after the type of shot indicates that it is an
initial broadside. Initial broadside were loaded with care before battle
and before the decks ran red with blood. As a consequence, initial
broadsides are a little more effective than broadsides loaded later. A
"*" after the type of shot indicates that the gun crews are still loading
it, and you cannot fire yet. "Hull" shows how much hull you have left.
"Crew" shows your three sections of crew. As your crew dies off, your
ability to fire decreases. "Guns" and "Carr" show your port and
starboard guns. As you lose guns, your ability to fire decreases.
"Rigg" shows how much rigging you have on your 3 or 4 masts. As rigging
is shot away, you lose mobility.
EFFECTIVENESS OF FIRE
It is very dramatic when a ship fires its thunderous broadsides, but the
mere opportunity to fire them does not guarantee any hits. Many factors
influence the destructive force of a broadside. First of all, and the
chief factor, is distance. It is harder to hit a ship at range ten than
it is to hit one sloshing alongside. Next is raking. Raking fire, as
mentioned before, can sometimes dismast a ship at range ten. Next, crew
size and quality affects the damage done by a broadside. The number of
guns firing also bears on the point, so to speak. Lastly, weather
affects the accuracy of a broadside. If the seas are high (5 or 6), then
the lower gunports of ships of the line can't even be opened to run out
the guns. This gives frigates and other flush decked vessels an
advantage in a storm. The scenario Pellew vs. The Droits de L'Homme
takes advantage of this peculiar circumstance.
REPAIRS
Repairs may be made to your Hull, Guns, and Rigging at the slow rate of
two points per three turns. The message "Repairs Completed" will be
printed if no more repairs can be made.
PECULIARITIES OF COMPUTER SHIPS
Computer ships in sail follow all the rules above with a few exceptions.
Computer ships never repair damage. If they did, the players could never
beat them. They play well enough as it is. As a consolation, the
computer ships can fire double shot every turn. That fluke is a good
reason to keep your distance. The driver figures out the moves of the
computer ships. It computes them with a typical distance function and a
depth-first search to find the maximum "score."
COMMANDS
Commands are given to sail by typing a single character. You will then
be prompted for further input.
f Fire broadsides if they bear
l Reload
L Unload broadsides (to change ammo)
m Move
i Print the closest ship
I Print all ships
F Find a particular ship or ships (e.g. "a?" for all Americans)
s Send a message around the fleet
b Attempt to board an enemy ship
B Recall boarding parties
c Change set of sail
r Repair
u Attempt to unfoul
g Grapple/ungrapple
v Print version number of game
CTRL/L Redraw screen
Q Quit
C Center your ship in the window
U Move window up
D, N Move window down
H Move window left
J Move window right
S Toggle window to follow your ship or stay where it is
SCENARIOS
Here is a summary of the scenarios in sail:
Ranger vs. Drake:
Wind from the N, blowing a fresh breeze.
(a) Ranger 19 gun Sloop (crack crew) (7 pts)
(b) Drake 17 gun Sloop (crack crew) (6 pts)
The Battle of Flamborough Head:
Wind from the S, blowing a fresh breeze.
This is John Paul Jones' first famous battle. Aboard the Bonhomme
Richard, he was able to overcome the Serapis's greater firepower by
quickly boarding her.
(a) Bonhomme Rich 42 gun Corvette (crack crew) (11 pts)
(b) Serapis 44 gun Frigate (crack crew) (12 pts)
Arbuthnot and Des Touches:
Wind from the N, blowing a gale.
(b) America 64 gun Ship of the Line (crack crew) (20 pts)
(b) Befford 74 gun Ship of the Line (crack crew) (26 pts)
(b) Adamant 50 gun Ship of the Line (crack crew) (17 pts)
(b) London 98 gun 3 Decker SOL (crack crew) (28 pts)
(b) Royal Oak 74 gun Ship of the Line (crack crew) (26 pts)
(f) Neptune 74 gun Ship of the Line (average crew) (24 pts)
(f) Duc Bougogne 80 gun 3 Decker SOL (average crew) (27 pts)
(f) Conquerant 74 gun Ship of the Line (average crew) (24 pts)
(f) Provence 64 gun Ship of the Line (average crew) (18 pts)
(f) Romulus 44 gun Ship of the Line (average crew) (10 pts)
Suffren and Hughes:
Wind from the S, blowing a fresh breeze.
(b) Monmouth 74 gun Ship of the Line (average crew) (24 pts)
(b) Hero 74 gun Ship of the Line (crack crew) (26 pts)
(b) Isis 50 gun Ship of the Line (crack crew) (17 pts)
(b) Superb 74 gun Ship of the Line (crack crew) (27 pts)
(b) Burford 74 gun Ship of the Line (average crew) (24 pts)
(f) Flamband 50 gun Ship of the Line (average crew) (14 pts)
(f) Annibal 74 gun Ship of the Line (average crew) (24 pts)
(f) Severe 64 gun Ship of the Line (average crew) (18 pts)
(f) Brilliant 80 gun Ship of the Line (crack crew) (31 pts)
(f) Sphinx 80 gun Ship of the Line (average crew) (27 pts)
Nymphe vs. Cleopatre:
Wind from the S, blowing a fresh breeze.
(b) Nymphe 36 gun Frigate (crack crew) (11 pts)
(f) Cleopatre 36 gun Frigate (average crew) (10 pts)
Mars vs. Hercule:
Wind from the S, blowing a fresh breeze.
(b) Mars 74 gun Ship of the Line (crack crew) (26 pts)
(f) Hercule 74 gun Ship of the Line (average crew) (23 pts)
Ambuscade vs. Baionnaise:
Wind from the N, blowing a fresh breeze.
(b) Ambuscade 32 gun Frigate (average crew) (9 pts)
(f) Baionnaise 24 gun Corvette (average crew) (9 pts)
Constellation vs. Insurgent:
Wind from the S, blowing a gale.
(a) Constellation 38 gun Corvette (elite crew) (17 pts)
(f) Insurgent 36 gun Corvette (average crew) (11 pts)
Constellation vs. Vengeance:
Wind from the S, blowing a fresh breeze.
(a) Constellation 38 gun Corvette (elite crew) (17 pts)
(f) Vengeance 40 gun Frigate (average crew) (15 pts)
The Battle of Lissa:
Wind from the S, blowing a fresh breeze.
(b) Amphion 32 gun Frigate (elite crew) (13 pts)
(b) Active 38 gun Frigate (elite crew) (18 pts)
(b) Volage 22 gun Frigate (elite crew) (11 pts)
(b) Cerberus 32 gun Frigate (elite crew) (13 pts)
(f) Favorite 40 gun Frigate (average crew) (15 pts)
(f) Flore 40 gun Frigate (average crew) (15 pts)
(f) Danae 40 gun Frigate (crack crew) (17 pts)
(f) Bellona 32 gun Frigate (green crew) (9 pts)
(f) Corona 40 gun Frigate (green crew) (12 pts)
(f) Carolina 32 gun Frigate (green crew) (7 pts)
Constitution vs. Guerriere:
Wind from the SW, blowing a gale.
(a) Constitution 44 gun Corvette (elite crew) (24 pts)
(b) Guerriere 38 gun Frigate (crack crew) (15 pts)
United States vs. Macedonian:
Wind from the S, blowing a fresh breeze.
(a) United States 44 gun Frigate (elite crew) (24 pts)
(b) Macedonian 38 gun Frigate (crack crew) (16 pts)
Constitution vs. Java:
Wind from the S, blowing a fresh breeze.
(a) Constitution 44 gun Corvette (elite crew) (24 pts)
(b) Java 38 gun Corvette (crack crew) (19 pts)
Chesapeake vs. Shannon:
Wind from the S, blowing a fresh breeze.
(a) Chesapeake 38 gun Frigate (average crew) (14 pts)
(b) Shannon 38 gun Frigate (elite crew) (17 pts)
The Battle of Lake Erie:
Wind from the S, blowing a light breeze.
(a) Lawrence 20 gun Sloop (crack crew) (9 pts)
(a) Niagara 20 gun Sloop (elite crew) (12 pts)
(b) Lady Prevost 13 gun Brig (crack crew) (5 pts)
(b) Detroit 19 gun Sloop (crack crew) (7 pts)
(b) Q. Charlotte 17 gun Sloop (crack crew) (6 pts)
Wasp vs. Reindeer:
Wind from the S, blowing a light breeze.
(a) Wasp 20 gun Sloop (elite crew) (12 pts)
(b) Reindeer 18 gun Sloop (elite crew) (9 pts)
Constitution vs. Cyane and Levant:
Wind from the S, blowing a moderate breeze.
(a) Constitution 44 gun Corvette (elite crew) (24 pts)
(b) Cyane 24 gun Sloop (crack crew) (11 pts)
(b) Levant 20 gun Sloop (crack crew) (10 pts)
Pellew vs. Droits de L'Homme:
Wind from the N, blowing a gale.
(b) Indefatigable 44 gun Frigate (elite crew) (14 pts)
(b) Amazon 36 gun Frigate (crack crew) (14 pts)
(f) Droits L'Hom 74 gun Ship of the Line (average crew) (24 pts)
Algeciras:
Wind from the SW, blowing a moderate breeze.
(b) Caesar 80 gun Ship of the Line (crack crew) (31 pts)
(b) Pompee 74 gun Ship of the Line (crack crew) (27 pts)
(b) Spencer 74 gun Ship of the Line (crack crew) (26 pts)
(b) Hannibal 98 gun 3 Decker SOL (crack crew) (28 pts)
(s) Real-Carlos 112 gun 3 Decker SOL (green crew) (27 pts)
(s) San Fernando 96 gun 3 Decker SOL (green crew) (24 pts)
(s) Argonauta 80 gun Ship of the Line (green crew) (23 pts)
(s) San Augustine 74 gun Ship of the Line (green crew) (20 pts)
(f) Indomptable 80 gun Ship of the Line (average crew) (27 pts)
(f) Desaix 74 gun Ship of the Line (average crew) (24 pts)
Lake Champlain:
Wind from the N, blowing a fresh breeze.
(a) Saratoga 26 gun Sloop (crack crew) (12 pts)
(a) Eagle 20 gun Sloop (crack crew) (11 pts)
(a) Ticonderoga 17 gun Sloop (crack crew) (9 pts)
(a) Preble 7 gun Brig (crack crew) (4 pts)
(b) Confiance 37 gun Frigate (crack crew) (14 pts)
(b) Linnet 16 gun Sloop (elite crew) (10 pts)
(b) Chubb 11 gun Brig (crack crew) (5 pts)
Last Voyage of the USS President:
Wind from the N, blowing a fresh breeze.
(a) President 44 gun Frigate (elite crew) (24 pts)
(b) Endymion 40 gun Frigate (crack crew) (17 pts)
(b) Pomone 44 gun Frigate (crack crew) (20 pts)
(b) Tenedos 38 gun Frigate (crack crew) (15 pts)
Hornblower and the Natividad:
Wind from the E, blowing a gale.
A scenario for you Horny fans. Remember, he sank the Natividad against
heavy odds and winds. Hint: don't try to board the Natividad, her crew
is much bigger, albeit green.
(b) Lydia 36 gun Frigate (elite crew) (13 pts)
(s) Natividad 50 gun Ship of the Line (green crew) (14 pts)
Curse of the Flying Dutchman:
Wind from the S, blowing a fresh breeze.
Just for fun, take the Piece of cake.
(s) Piece of Cake 24 gun Corvette (average crew) (9 pts)
(f) Flying Dutchy 120 gun 3 Decker SOL (elite crew) (43 pts)
The South Pacific:
Wind from the S, blowing a strong breeze.
(a) USS Scurvy 136 gun 3 Decker SOL (mutinous crew) (27 pts)
(b) HMS Tahiti 120 gun 3 Decker SOL (elite crew) (43 pts)
(s) Australian 32 gun Frigate (average crew) (9 pts)
(f) Bikini Atoll 7 gun Brig (crack crew) (4 pts)
Hornblower and the battle of Rosas
Wind from the E, blowing a fresh breeze.
The only battle Hornblower ever lost. He was able to dismast one
ship and stern rake the others though. See if you can do as well.
(b) Sutherland 74 gun Ship of the Line (crack crew) (26 pts)
(f) Turenne 80 gun 3 Decker SOL (average crew) (27 pts)
(f) Nightmare 74 gun Ship of the Line (average crew) (24 pts)
(f) Paris 112 gun 3 Decker SOL (green crew) (27 pts)
(f) Napolean 74 gun Ship of the Line (green crew) (20 pts)
Cape Horn:
Wind from the NE, blowing a strong breeze.
(a) Concord 80 gun Ship of the Line (average crew) (27 pts)
(a) Berkeley 98 gun 3 Decker SOL (crack crew) (28 pts)
(b) Thames 120 gun 3 Decker SOL (elite crew) (43 pts)
(s) Madrid 112 gun 3 Decker SOL (green crew) (27 pts)
(f) Musket 80 gun 3 Decker SOL (average crew) (27 pts)
New Orleans:
Wind from the SE, blowing a fresh breeze.
Watch that little Cypress go!
(a) Alligator 120 gun 3 Decker SOL (elite crew) (43 pts)
(b) Firefly 74 gun Ship of the Line (crack crew) (27 pts)
(b) Cypress 44 gun Frigate (elite crew) (14 pts)
Botany Bay:
Wind from the N, blowing a fresh breeze.
(b) Shark 64 gun Ship of the Line (average crew) (18 pts)
(f) Coral Snake 44 gun Corvette (elite crew) (24 pts)
(f) Sea Lion 44 gun Frigate (elite crew) (24 pts)
Voyage to the Bottom of the
Wind from the NW, blowing a fresh breeze.
This one is dedicated to Richard Basehart and David Hedison.
(a) Seaview 120 gun 3 Decker SOL (elite crew) (43 pts)
(a) Flying Sub 40 gun Frigate (crack crew) (17 pts)
(b) Mermaid 136 gun 3 Decker SOL (mutinous crew) (27 pts)
(s) Giant Squid 112 gun 3 Decker SOL (green crew) (27 pts)
Frigate Action:
Wind from the E, blowing a fresh breeze.
(a) Killdeer 40 gun Frigate (average crew) (15 pts)
(b) Sandpiper 40 gun Frigate (average crew) (15 pts)
(s) Curlew 38 gun Frigate (crack crew) (16 pts)
The Battle of Midway:
Wind from the E, blowing a moderate breeze.
(a) Enterprise 80 gun Ship of the Line (crack crew) (31 pts)
(a) Yorktown 80 gun Ship of the Line (average crew) (27 pts)
(a) Hornet 74 gun Ship of the Line (average crew) (24 pts)
(j) Akagi 112 gun 3 Decker SOL (green crew) (27 pts)
(j) Kaga 96 gun 3 Decker SOL (green crew) (24 pts)
(j) Soryu 80 gun Ship of the Line (green crew) (23 pts)
Star Trek:
Wind from the S, blowing a fresh breeze.
(a) Enterprise 450 gun Ship of the Line (elite crew) (75 pts)
(a) Yorktown 450 gun Ship of the Line (elite crew) (75 pts)
(a) Reliant 450 gun Ship of the Line (elite crew) (75 pts)
(a) Galileo 450 gun Ship of the Line (elite crew) (75 pts)
(k) Kobayashi Maru 450 gun Ship of the Line (elite crew) (75 pts)
(k) Klingon II 450 gun Ship of the Line (elite crew) (75 pts)
(o) Red Orion 450 gun Ship of the Line (elite crew) (75 pts)
(o) Blue Orion 450 gun Ship of the Line (elite crew) (75 pts)
IMPLEMENTATION
sail is really two programs in one. Each player starts up a process
which runs his own ship. In addition, a driver process is forked (by the
first player) to run the computer ships and take care of global
bookkeeping.
Because the driver must calculate moves for each ship it controls, the
more ships the computer is playing, the slower the game will appear.
If a player joins a game in progress, he will synchronize with the other
players (a rather slow process for everyone), and then he may play along
with the rest.
To implement a multi-user game, the communicating processes must use a
common temporary file as a place to read and write messages. In
addition, a locking mechanism must be provided to ensure exclusive access
to the shared file. For example, sail uses a temporary file named
/tmp/#sailsink.21 for scenario 21, and corresponding file names for the
other scenarios. To provide exclusive access to the temporary file, sail
uses a technique stolen from an old game called "pubcaves" by Jeff Cohen.
Processes do a busy wait in the loop
for (n = 0; link(sync_file, sync_lock) < 0 && n < 30; n++)
sleep(2);
until they are able to create a link to a file named /tmp/#saillock.??.
The "??" correspond to the scenario number of the game. Since UNIX
guarantees that a link will point to only one file, the process that
succeeds in linking will have exclusive access to the temporary file.
CONSEQUENCES OF SEPARATE PLAYER AND DRIVER
When players do something of global interest, such as moving or firing,
the driver must coordinate the action with the other ships in the game.
For example, if a player wants to move in a certain direction, he writes
a message into the temporary file requesting the driver to move his ship.
Each "turn," the driver reads all the messages sent from the players and
decides what happened. It then writes back into the temporary file new
values of variables, etc.
The most noticeable effect this communication has on the game is the
delay in moving. Suppose a player types a move for his ship and hits
return. What happens then? The player process saves up messages to be
written to the temporary file in a buffer. Every 7 seconds or so, the
player process gets exclusive access to the temporary file and writes out
its buffer to the file. The driver, running asynchronously, must read in
the movement command, process it, and write out the results. This takes
two exclusive accesses to the temporary file. Finally, when the player
process gets around to doing another 7 second update, the results of the
move are displayed on the screen. Hence, every movement requires four
exclusive accesses to the temporary file (anywhere from 7 to 21 seconds
depending upon asynchrony) before the player sees the results of his
moves.
In practice, the delays are not as annoying as they would appear. There
is room for "pipelining" in the movement. After the player writes out a
first movement message, a second movement command can then be issued.
The first message will be in the temporary file waiting for the driver,
and the second will be in the file buffer waiting to be written to the
file. Thus, by always typing moves a turn ahead of the time, the player
can sail around quite quickly.
If the player types several movement commands between two 7 second
updates, only the last movement command typed will be seen by the driver.
Movement commands within the same update "overwrite" each other, in a
sense.