PPT Slide
The most basic developmental choice is that of the computing environment(which may be considered as the hardware and operating system employed). Historically major business systems were developed on the proprietary hardware and operating system of a major computer company. Examples were IBM's MVS or DEC's VMS.
The advent of the personal computer with its fairly monolithic operating environment paralleled the evolution of the "Open Systems" environment for multi-user applications. The various flavors of UNIX, LINUX and Windows NT belong in this grouping. The standards that form the basis of "Open Systems" permit the same application to run on a variety of computing platforms from various vendors. Even if a customer's legacy information systems run on a proprietary environment such as IBM AS/400, facilities are commonplace that make it easy to interface with "Open Systems" based applications. Hence WISL selected "Open Systems" as the computing environment on which to offer its products.