Database Technology

If there was one single cause that precipitated the development of database systems, it was the large-scale introduction of cheap direct-access mass storage in the form of magnetic disks. Up to then all mass-storage handling was in the form of sequential file processing. With the advent of disks, index-sequential files appeared at first, to be followed within a few years’ time — at the end of the 1960s — by the first database systems. Since then, database technology has gone through a period of steady evolution towards mature software products as we know them today. And more importantly: the technology is well-prepared not only to survive all the new trends in hardware and system software such as novel processor architectures, workstations, computer networking, high-resolution screens, windowing and high-density magnetic and optic disks, but also to make the best possible use of these trends. The “best possible use” will, of course, be dictated as much by an application as by the underlying technologies. It is the first aspect, the usefulness to the application world, and in particular to engineering applications, which is the subject of Chap. 2.