The degree to which a system, product, or component can be migrated from one hardware, software, or other operating (or using) environment to another.

The ability of software on a computer to be transferred to another computer. Software migration is an equivalent relation to the realization of functions, not an equivalent relation. The main mark of software portability is: this kind of software has a common standard text; They are independent of the specific computer

The independence of software relative to a specific computer, in a narrow sense, means that portable software should be independent of the computer hardware environment; In a broad sense, portable software should also be independent of computer software, that is, high-level standardized software, whose functions are independent of machine system structure and can cross many machine boundaries. When porting software from one computer to another, consider first the interface of the ported software to the host hardware and operating system, and then try to replace it with the interface to the target machine. Therefore, whether the interface transformation is easy or not is one of the main indicators to measure the portability of a software