Let’s start by taking a brief look at the history of database use, before introducing the architecture of the future. As you can see in Figure 1-1, we will not refer to dates, but version numbers, going back to the time when the Oracle Database became predominant.
When Oracle Database 8i and 9i were on the market, midrange computers became prevalent in data centers. We were moving from the mainframe era to a client/server era, and Oracle architecture was very well suited for that. Written in the C programming language, it was available on multiple platforms and with all user management contained within its data dictionary. It was ready for the client/server architecture, using the OS only to listen on a TCP/IP port and to store files. Furthermore, the architecture was scalable on minicomputers, thanks to the parallel server feature, which would later become RAC (Real Application Clusters).