ITecture, operating system> IBM PC software that runs in a 32-bITflat 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 PCclones became 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)
