ChiteCture, operating system> IBM PC software that runs in a 32-bit flat address spaCe. The term 32-bit appliCationCame 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)
