Computer Languages

Fourth-generation languages attempt to make communicating with computers as much like the processes of thinking and talking to other people as possible. The problem is that the computer still only understands zeros and ones, so a compiler and interpreter must still convert the source code into the machine code that the computer can understand. Fourth-generation languages typically consist of English-like words and phrases. When they are implemented on microcomputers, some of these languages include graphic devices such as icons and onscreen push buttons for use during programming and when running the resulting application.

Many fourth-generation languages use Structured Query Language (SQL) as the basis for operations. SQL was developed at IBM to develop information stored in relational databases. Eventually, it was adopted by the American National Standards Institute (ANSI) and later by the International Standards Organization (ISO) as a means of managing structured, factual data. Many database companies offer an SQL-type database because purchasers of such databases seek to optimize their investments by buying open databases, i.e., those offering the greatest compatibility with other systems. This means that the information systems are relatively independent of vendor, operating system, and computer platform.

Examples of fourth-generation languages include PROLOG, an artificial intelligence language that applies rules to data to arrive at solutions; and OCCAM and PARLOG, both parallel-processing languages. Newer languages may combine SQL and other high-level languages. IBM's Sonnet is being modified to use sound rather than visual images as a computer interface.

In 1991, development began on a refinement of C++ that would be adaptable to the Internet. The result, in 1995, was Java. The program formed the basis of the Netscape Internet browser. Java enables files to be acquired from the Internet in order to run programs or subprograms. This adaptability has made Java a very popular language.