IBM OS 2 Question:

Your system performance depends largely on how OS/2 Warp 4 and the underlying hardware work together. The 32-bit OS/2 Warp 4 operating system exploits the Intel 32-bit X-86 architecture through the flat memory model, native protected mode and virtual 8086 mode though paging and multiple virtual DOS machine sessions. The flat memory model allows for a very large (4 GB) single address space referred to as flat memory. Call/return times are reduced by eliminating the need to switch segments manifested in a typical 16-bit application.