In computer science, an anonymous pipe is a simplexFIFO communication channel that may be used for one-way interprocess communication (IPC). An implementation is often integrated into the operating system's file IO subsystem. Typically a parent program opens anonymous pipes, and creates a new process that inherits the other ends of the pipes, or creates several new processes and arranges them in a pipeline.
Full-duplex (two-way) communication normally requires two anonymous pipes.
Pipelines are supported in most popular operating systems, from Unix and DOS onwards, and are created using the "|" character.
Pipelines are an important part of many traditional Unix applications and support for them is well integrated into most Unix-like operating systems. Pipes are created using the pipesystem call, which creates a new pipe and returns a pair of file descriptors referring to the read and write ends of the pipe. Many traditional Unix programs are designed as filters to work with pipes.
The concept of pipelines was invented by Douglas McIlroy at Unix's ancestral home of Bell Labs, prior to the actual invention of the operating system, and implemented in Unix at his insistence, shaping its toolbox philosophy. It is named by analogy to a physical pipeline. The standard shell syntax for pipelines is to list multiple programs to invoke in one command, separated by vertical bars:
Each program is assumed to take input and give output on its standard streams. Each "|" tells the shell to connect the standard output of the left program to the standard input of the right program by an inter-process communication mechanism called an (anonymous) pipe, implemented in the operating system. Since pipes are unidirectional, data flows through the pipeline from left to right.
An organ pipe is a sound-producing element of the pipe organ that resonates at a specific pitch when pressurized air (commonly referred to as wind) is driven through it. Each pipe is tuned to a specific note of the musical scale. A set of organ pipes of similar timbre tuned to a scale is known as a rank or a stop.
Metal pipes are usually made of lead; for increased rigidity it is alloyed with tin along with trace amounts of antimony and copper. The percentage of each metal in the alloy influences the characteristics of the resulting pipe. A high proportion of tin results in a slightly brighter colouring. In addition, high amounts of tin give a gleaming and long-lasting polish, which may be desired if the pipe is clearly visible. The cost of each metal is also a factor, as tin is more expensive than lead. Cost considerations may also lead to the use of the inferior rolled zinc especially for the lower tones that take a lot of material. In addition, pipes have been made of many metals, including copper, aluminium, goldelectroplate, silver, brass, and iron.
The Pennsylvanian is a once a day replacement of the Keystone service between New York and Pittsburgh, offering Business Class seating as an upgrade to the coach-only seating on Keystone trains. Prior to Amtrak, the route was known as the Duquesne, named after Fort Duquesne in Pittsburgh, and operated by the Pennsylvania Railroad. The Pennsylvanian began on April 27, 1980, as a state-supported daylight train between Philadelphia and Pittsburgh, with connecting service to New York. Amtrak would later extend the train to serve New York directly. Between 1998–2005 Amtrak shifted the endpoints west to Chicago and Philadelphia, providing daylight service to Cleveland, Ohio. In 2005 the Pennsylvanian reverted to a Pittsburgh–New York schedule. On its inauguration the Pennsylvanian used Amfleet equipment and continues to be so equipped.
Fable II Pub Games is an Xbox Live Arcade title that includes three pub game-styled minigames called Keystone, Fortune's Tower and Spinnerbox for the Xbox 360, developed by Carbonated Games under the supervision of Lionhead Studios, which all share functionality with Fable II. The games are included in both editions of Fable II. Fable II Pub Games was also free for those who pre-ordered Fable II from participating retailers.
The Pub Games offer players a chance to win money and items for their Fable II character, to be given to them once their character has reached adulthood. For every piece of gold won in the tournament section of Pub Games, a piece of gold is added to the Fable II character's wallet, giving players a chance to have a rich character from the start of the game. Conversely, if the player accumulates debt in the Pub Games, negative consequences will befall their character. Fifteen unique items can also be won in the Pub Games' tournaments, ranging from weapons to clothing or tattoos that can be used by their Fable II character.