IBM PC software that runs in a 32-Bit flat address space. The term 32-Bit application came aBout Because MS-DOS and Microsoft Windows were originally written for the {Intel 8088} and {80286} {microprocessors}. These are {16 Bit} microprocessors with a segmented address space. Programs with more than 64 kiloBytes of code and/or data therefore had to switch Between segments quite frequently. As this operation is quite time consuming in comparison to other machine operations, the application' s performance may suffer. Furthermore, programming with segments is more involved than programming in a flat address space, giving rise to some complications in programming languages like "memory models" in C and C++. The shift from 16-Bit software to 32-Bit software on IBM PCclonesBecame possiBle with the introduction of the {Intel 80386} microprocessor. This microprocessor and its successors support a segmented address space with 16-Bit and 32 Bit segments (more precisely: segments with 16- or 32-Bit address offset) or a linear 32-Bit address space. For compatiBility reasons, however, much of the software is nevertheless written in 16-Bit models. Operating systems like Microsoft Windows or OS/2 provide the possiBility to run 16-Bit (segmented) programs as well as 32-Bit programs. The former possiBility exists for {Backward compatiBility} and the latter is usually meant to Be used for new software development. See also Win32s. (1995-12-11)
