Stand-alone

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Stand-alone is a loosely defined term used to sort computer programs. It tries to draw some distinction between programs invoked by some computer event and those invoked by other programs.

However this distinction does not stand up to scrutiny outside the context of certain embedded systems, since the computer has usually to be running some program that prepares (and sometimes initially processes) the "stand-alone" program to begin with. Hence all programs are launched or prepared/processed by other programs (with the sole exception of the bootstrap loader), and no code can really be said to stand alone.

If "stand-alone" is more widely defined as a program not needing the services of other programs (except maybe firmware) once it is running, then most operating systems can also justifiably be called "stand-alone", since they need the bootstrap loader only for starting up. This is the definition of a "stand-alone application" that is used e.g. in the C programming language standards. Normal applications are called "hosted applications" in contrast.

In some embedded systems, the one and only application that they run is truly stand-alone, in the sense that it includes all the code that's ever going to be seen by the CPU of those systems. This kind of application has to contain its own (possibly very basic) operating system.

A distinction might be drawn between programs that run as operating system processes and those that are loaded as an add-on in the context of an existing process, e.g. a plugin. This distinction may make some sense, but the term "stand-alone" has been used inconsistently: for instance, on the Macintosh platform, the plugin code has often been referred to as being stand-alone.

A less ambiguous terminology refers to application and non-application code, since "application" seems to be a commonly-accepted cross-platform term for a program that runs as a separate process and is invoked as a direct result of some user action. The "non-application" code then has to be loaded and run as part of the process context of the "application" code, and there is no ambiguity about which is which.

[edit] Other usages

In computer games, a stand-alone game is one that can be played without requiring another game to provide most of its operating code (as opposed to an expansion pack, which adds to a previous game).

Computers themselves are often termed "stand-alone" if they are not connected to a network.

In serial fiction, such as a television series or comic books, stand-alone refers to a story that is unrelated or unconnected to the broader plots of the overall series; it "stands alone" and can be enjoyed without detailed knowledge of the rest of the series (or of storylines that are active at the time of the "stand-alone" material's release), or missed without impacting one's understanding of the series.

In molecular biology, the term "stand-alone protein domain" refers to protein domains that exist as a single domain, and as such are believed to perform a single function. Sometimes, these domains are also found in a non-stand-alone context, fused to other protein domains that have a different function. Well-known examples of stand-alone domains are ligand-sensing regulatory domains, that exist as single-domain proteins, but also fused to other domains as part of multi-domain proteins, such as enzymes or transcriptional regulators.

In baking, the term refers to cupcakes molds that do not need a cupcake pan to hold themselves up.