Evolution of Software Technology

This chapter reviews the evolution of software technology with its emphasis on the concepts of virtual memory, 64-bit architecture, operating systems, web servers, object models, and security models. Virtual memory eases software development by releasing programmers from some aspects of memory management. Virtual memory gives operating system (OS) the responsibility to manage the memory hierarchy, in a manner invisible to the applications programmer, enabling the use of objects, code, or data larger than the available physical memory without any explicit management activities on the programmer's part. 64-bit architecture offers several advantages primarily supporting directly and efficiently files or filing systems whose size is greater than two to four GB. The market share of operating systems is continually evolving. The choice of operating systems depends upon its scalability, reliability, availability and serviceability (RAS), distributed services and internet support, and system management. Web service is an interface that describes a collection of services accessible over the network by means of XML messages. It is noted that with the goal of facilitating web-based business transactions, elements, which form service architecture, are standardized.