Porting older software(8086)

Small programs could ignore the segmentation and just use plain 16-bit addressing. This allowed 8-bit software to be quite easily ported to the 8086. The authors of MS-DOS took advantage of this by providing an Application Programming Interface very similar to CP/M as well as including the simple .com executable file format, identical to CP/M. This was important when the 8086 and MS-DOS was new, because it allowed many existing CP/M (and other) applications to be quickly made available, greatly easing the acceptance of new platform