I had a front row seat at Microsoft to watch the first two application model transitions. Early mainframe and minicomputer systems were monolithic, with data storage, application code, and terminal services all in one box. When the microprocessor and Ethernet networks emerged during the 1980’s, they enabled lower-cost computers to work together and communicate over local area networks. PC’s and Unix workstations began to connect to servers, leveraging a new, multi-machine, client-server programming model for business applications. Client-server applications emerged with a graphical user interface coupled to a back-end SQL database (frequently Oracle Database or SQL Server).
Client-server applications were