1.2 Types of Computer Languages

The earliest computers had to be programmed by people who knew the detailed capabilities and limitations of the hardware. Memory was an especially precious resource, and great care and ingenuity were required to squeeze algorithms into the extremely limited space available. Subsequently, as the overall capabilities of computers improved and use became widespread, successive generations of computer languages were devised in order to improve programmer productivity and accuracy at the expense of performance and resources. Table 1-1 shows the progression of programming languages, where n GL means nth generation language.

Assembly language lies between machine language and higher-level languages, such as C or Pascal. Assembly language more precisely expresses the constraints of an architecture than do high-level programming languages, but the latter are more amenable to reuse of code segments and global optimization. Accordingly, learning at least one assembly language can lead to an appreciation of what high-level languages actually do behind the scenes.