Tell-tale
Encyclopedia
A tell-tale or telltale is an indicator, signal, or sign that conveys the status of a situation, mechanism, or system.
to inform the driver that a system or device is operating, switched on, or that a problem has occurred with the vehicle.
context a tell-tale, sometimes known as a tell-tail, is a piece of cloth or fabric that is tied or attached to a stay
, any of several wires which hold a mast
in place on a sailboat
. Usually there will be one tell-tale on the port stay and one on a starboard stay.
Tell-tales can also be attached to a sail
, used as a guide when trimming (adjusting) a sail. On the mainsail
tell-tales are on the leech (aft edge) and when trimmed properly should be streaming backwards. On the jib
there are tell-tales on both sides of the luff of the sail. As a general guide, the windward tell-tale should stream aft (backwards) with an occasional lift, the leeward front tell-tale should stream aft. If one tell-tale begins to spiral, it is indicating the sail has incorrect air flow on that side. To correct this the sail needs to move towards that side.
A tell-tale compass is a special compass installed in the ceiling of a cabin and which can be read from below, for example when one is resting on a bed, or from the side in a mirror showing the card's underside. According to Herman Melville's Moby Dick, a tell-tale refers to the cabin-compass, "because without going to the compass at the helm, the captain, while below, can inform himself of the course of the ship."
spacecraft contains a tell-tale, developed by the University of Aarhus
in Denmark
, as part of its Meteorological Station. It is a small tube that is deflected by the martian
wind. The science payload’s stereo camera
recorded images of the tell-tale that are used to determine wind direction and speed.
the tell-tales are longitudinal holes drilled in the stays of the firebox to provide early warning of corrosion
.
A tell-tale is also a series of ropes suspended over the tracks above the height of a boxcar. These ropes are intended to give warning to a brakeman on the roof of the train that the train is approaching a low-clearance obstacle, such as a tunnel or a bridge. A Chesapeake and Ohio Railway
tell-tale had 17 of these ropes hanging from a tube suspended across the track, the bottom of the ropes 12" lower than the height of the obstruction, and placed 100 to 300 feet before the obstruction. On British Mark 1 carriages, a Tell Tale connects the emergency (communication) cord or chain to the train line to facilitate an emergency stop.
a tell-tale is a string of characters that occurs only within one language within a group of languages. A reader can be completely certain which language they are reading if he or she comes across a tell-tale. In this sense, a tell tale is a dead give away of what the language is.
More formally, a tell-tale of a member L of some language
class is a finite subset
of L such that no other language containing the subset in the class is a proper subset of L. In other words, a tell-tale is a finite subset that makes a language being a minimal consistent one in the class. The term is used in the field of artificial intelligence
and machine language learning
as well as linguistics.
Automotive
In a vehicle, a tell-tale is an indicator on or near the dashboardDashboard
A dashboard is a control panel placed in front of the driver of an automobile, housing instrumentation and controls for operation of the vehicle....
to inform the driver that a system or device is operating, switched on, or that a problem has occurred with the vehicle.
Sailing
In a nautical or sailingSailing
Sailing is the propulsion of a vehicle and the control of its movement with large foils called sails. By changing the rigging, rudder, and sometimes the keel or centre board, a sailor manages the force of the wind on the sails in order to move the boat relative to its surrounding medium and...
context a tell-tale, sometimes known as a tell-tail, is a piece of cloth or fabric that is tied or attached to a stay
Stays (nautical)
Stays are the heavy ropes, wires, or rods on sailing vessels that run from the masts to the hull, usually fore-and-aft along the centerline of the vessel...
, any of several wires which hold a mast
Mast (sailing)
The mast of a sailing vessel is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship...
in place on a sailboat
Sailboat
A sailboat or sailing boat is a boat propelled partly or entirely by sails. The term covers a variety of boats, larger than small vessels such as sailboards and smaller than sailing ships, but distinctions in the size are not strictly defined and what constitutes a sailing ship, sailboat, or a...
. Usually there will be one tell-tale on the port stay and one on a starboard stay.
Tell-tales can also be attached to a sail
Sail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
, used as a guide when trimming (adjusting) a sail. On the mainsail
Mainsail
A mainsail is a sail located behind the main mast of a sailing vessel.On a square rigged vessel, it is the lowest and largest sail on the main mast....
tell-tales are on the leech (aft edge) and when trimmed properly should be streaming backwards. On the jib
Jib
A jib is a triangular staysail set ahead of the foremast of a sailing vessel. Its tack is fixed to the bowsprit, to the bow, or to the deck between the bowsprit and the foremost mast...
there are tell-tales on both sides of the luff of the sail. As a general guide, the windward tell-tale should stream aft (backwards) with an occasional lift, the leeward front tell-tale should stream aft. If one tell-tale begins to spiral, it is indicating the sail has incorrect air flow on that side. To correct this the sail needs to move towards that side.
A tell-tale compass is a special compass installed in the ceiling of a cabin and which can be read from below, for example when one is resting on a bed, or from the side in a mirror showing the card's underside. According to Herman Melville's Moby Dick, a tell-tale refers to the cabin-compass, "because without going to the compass at the helm, the captain, while below, can inform himself of the course of the ship."
Space
The PhoenixPhoenix (spacecraft)
Phoenix was a robotic spacecraft on a space exploration mission on Mars under the Mars Scout Program. The Phoenix lander descended on Mars on May 25, 2008...
spacecraft contains a tell-tale, developed by the University of Aarhus
University of Aarhus
Aarhus University , located in the city of Aarhus, Denmark, is Denmark's second oldest and second largest university...
in Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
, as part of its Meteorological Station. It is a small tube that is deflected by the martian
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
wind. The science payload’s stereo camera
Stereo camera
A stereo camera is a type of camera with two or more lenses with a separate image sensor or film frame for each lens. This allows the camera to simulate human binocular vision, and therefore gives it the ability to capture three-dimensional images, a process known as stereo photography. Stereo...
recorded images of the tell-tale that are used to determine wind direction and speed.
Railroad
In a steam locomotiveSteam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
the tell-tales are longitudinal holes drilled in the stays of the firebox to provide early warning of corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
.
A tell-tale is also a series of ropes suspended over the tracks above the height of a boxcar. These ropes are intended to give warning to a brakeman on the roof of the train that the train is approaching a low-clearance obstacle, such as a tunnel or a bridge. A Chesapeake and Ohio Railway
Chesapeake and Ohio Railway
The Chesapeake and Ohio Railway was a Class I railroad formed in 1869 in Virginia from several smaller Virginia railroads begun in the 19th century. Led by industrialist Collis P...
tell-tale had 17 of these ropes hanging from a tube suspended across the track, the bottom of the ropes 12" lower than the height of the obstruction, and placed 100 to 300 feet before the obstruction. On British Mark 1 carriages, a Tell Tale connects the emergency (communication) cord or chain to the train line to facilitate an emergency stop.
Linguistics
In linguisticsLinguistics
Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....
a tell-tale is a string of characters that occurs only within one language within a group of languages. A reader can be completely certain which language they are reading if he or she comes across a tell-tale. In this sense, a tell tale is a dead give away of what the language is.
More formally, a tell-tale of a member L of some language
Formal language
A formal language is a set of words—that is, finite strings of letters, symbols, or tokens that are defined in the language. The set from which these letters are taken is the alphabet over which the language is defined. A formal language is often defined by means of a formal grammar...
class is a finite subset
Subset
In mathematics, especially in set theory, a set A is a subset of a set B if A is "contained" inside B. A and B may coincide. The relationship of one set being a subset of another is called inclusion or sometimes containment...
of L such that no other language containing the subset in the class is a proper subset of L. In other words, a tell-tale is a finite subset that makes a language being a minimal consistent one in the class. The term is used in the field of artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
and machine language learning
Machine learning
Machine learning, a branch of artificial intelligence, is a scientific discipline concerned with the design and development of algorithms that allow computers to evolve behaviors based on empirical data, such as from sensor data or databases...
as well as linguistics.