portability

operating system, programming The ease with which a piece of

software (or file format) can be "ported", i.e. made to run

on a new platform and/or compile with a new compiler.

The most important factor is the language in which the

software is written and the most portable language is almost

certainly C (though see Vaxocentrism for counterexamples).

This is true in the sense that C compilers are available for

most systems and are often the first compiler provided for a

new system. This has led several compiler writers to compile

other languages to C code in order to benefit from its

portability (as well as the quality of compilers available for

it).

The least portable type of language is obviously assemblycode since it is specific to one particular (family of)

processor(s). It may be possible to translate mechanically

from one assembly code (or even machine code) into another

but this is not really portability. At the other end of the

scale would come interpreted or semi-compiled languages

such as LISP or Java which rely on the availability of a

portable interpreter or virtual machine written in a lower

level language (often C for the reasons outlined above).

The act or result of porting a program is called a "port".

E.g. "I've nearly finished the Pentium port of my big bang

simulation."

Portability is also an attribute of file formats and depends

on their adherence to standards (e.g. ISO 8859) or the

availability of the relevant "viewing" software for different

platforms (e.g. PDF).

(1997-06-18)