On the fly is a phrase used to describe something that is being changed while the process that the change affects is ongoing. It is used in the automotive, computer, and culinary industries. In cars, on the fly can be used to describe the changing of the cars configuration while it is still driving. Processes that can occur while the car is still driving include switching between two wheel drive and four wheel drive on some cars and opening and closing the roof on some convertible cars. In computing, on the fly CD writers can read from one CD and write the data to another without saving it on a computer's memory. Switching programs or applications on the fly in multi-tasking operating systems means the ability to switch between native and/or emulated programs or applications that are still running and running in parallel while performing their tasks or processes, but without pausing, freezing, or delaying any, or other unwanted events. Switching computer parts on the fly means computer parts are replaced while the computer is still running. It can also be used in programming to describe changing a program while it is still running. In restaurants and other places involved in the preparation of food, the term is used to indicate that an order needs to be made right away.

Colloquial usage

In colloquial use, "on the fly" means something created when needed. The phrase is used to mean: # something that was not planned ahead # changes that are made during the execution of same activity:

ex tempore ''Ex tempore'' (Latin for "out of the moment“) is a legal term that means 'at the time'. A judge who hands down a decision in a case soon or straight after hearing it is delivering a decision ''ex tempore''. Another way a judge may deliver a de ...

impromptu An impromptu (, , loosely meaning "offhand") is a free-form musical composition with the character of an ''ex tempore'' improvisation as if prompted by the spirit of the moment, usually for a solo instrument, such as piano. According to ''Allgeme ...

Automotive usage

In the automotive industry, the term refers to the circumstance of performing certain operations while a vehicle is driven by the engine and moving. In reference to

four-wheel drive Four-wheel drive, also called 4×4 ("four by four") or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer ca ...

vehicles, this term describes the ability to change from two to four-wheel drive while the car is in gear and moving. In some

convertible A convertible or cabriolet () is a passenger car that can be driven with or without a roof in place. The methods of retracting and storing the roof vary among eras and manufacturers. A convertible car's design allows an open-air driving expe ...

models, the roof can be folded electrically on the fly, whereas in other cases the car must be stopped. In harvesting machines, newer monitoring systems let the driver track the quality of the grain, while enabling them to adjust the rotor speed on the fly as harvesting progresses.

Computer usage

In multitasking computing an operating system can handle several programs, both native applications or emulated software, that are running independent, parallel, together in the same time in the same device, using separated or shared resources and/or data, executing their tasks separately or together, while a user can switch on the fly between them or groups of them to use obtained effects or supervise purposes, without waste of time or waste of performance. In operating systems using

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

very often it is done by switching from an active window (or an object playing similar role) of a particular software piece to another one but of another software. A computer can compute results on the fly, or retrieve a previously stored result. It can mean to make a copy of a removable media (

CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both com ...

, DVD, etc.) directly, without first saving the source on an intermediate medium (a harddisk); for example, copying a CD-ROM from a CD-ROM drive to a CD-Writer drive. The copy process requires each block of data to be retrieved and immediately written to the destination, so that there is room in the working memory to retrieve the next block of data. When used for encrypted data storage, ''on the fly'' the

data stream In connection-oriented communication, a data stream is the transmission of a sequence of digitally encoded coherent signals to convey information. Typically, the transmitted symbols are grouped into a series of packets. Data streaming has b ...

is automatically encrypted as it is written and decrypted when read back again, transparently to software. The acronym OTFE is typically used. On-the-fly programming is the technique of modifying a program without stopping it. A similar concept,

hot swapping Hot swapping is the replacement or addition of components to a computer system without stopping, shutting down, or rebooting the system; hot plugging describes the addition of components only. Components which have such functionality are said ...

, refers to on-the-fly replacement of computer hardware.

On-the-fly computing

On-the-fly computing (OTF computing) is about automating and customizing software tailored to the needs of a user. According to a requirement specification, this software is composed of basic components, so-called basic services, and a user-specific setting of these basic components is made. Accordingly, the requested services are compiled only at the request of the user and then run in a specially designed data center to make the user the functions of the (on-the-fly) created service accessible.

Restaurant usage

In restaurants, cafes, banquet halls, and other places involved in the preparation of food, the term is used to indicate that an order needs to be made right away. This is often because a previously-served dish is inedible, because a waiter has made a mistake or delayed, or because a guest has to leave promptly.

Usage in sports

ice hockey Ice hockey (or simply hockey) is a team sport played on ice skates, usually on an ice skating rink with lines and markings specific to the sport. It belongs to a family of sports called hockey. In ice hockey, two opposing teams use ice ...

, it is both legal and common for teams to make line changes (player substitutions) when the puck is in play. Such line changes are referred to as being done "on the fly".

References

{{Reflist Computer jargon category:Restaurant terminology Technical terminology