Programming Environments

The term programming environment is sometimes reserved for environments containing language specific editors and source level debugging facilities; here, the term will be used in its broader sense to refer to all of the hardware and software in the environment used by the programmer. All programming can therefore be properly described as takin place in a programming environment.
Programming environments may vary considerably in complexity. An example of a simple environment might consist of a text editor for program preparation, an assembler for translating programs to machine language, and a simple operating system consisting of input-output drivers and a file system. Although card input and non-interactive operation characterized most early computer systems, such simple environments were supported on early experimental time-sharing systems by 1963.
Although such simple programming environments are a great improvement over the bare hardware, tremendous improvements are possible. The first improvement which comes to mind is the use of a high level language instead of an assembly language, but this implies other changes. Most high level languages require more complicated run-time support than just input-output drivers and a file system. For example, most require an extensive library of predefined procedures and functions, many require some kind of automatic storage management, and some require support for concurrent execution of threads, tasks or processes within the program.
Many applications require additional features, such as window managers or elaborate file access methods. When multiple applications coexist, perhaps written by different programmers, there is frequently a need to share files, windows or memory segments between applications. This is typical of today's electronic mail, database, and spreadsheet applicatons, and the programming environments that support such applications can be extremely complex, particularly if they attempt to protect users from malicious or accidental damage caused by program developers or other users.
A programming environment may include a number of additional features which simplify the programmer's job. For example, library management facilities to allow programmers to extend the set of predefined procedures and functions with their own routines. Source level debugging facilities, when available, allow run-time errors to be interpreted in terms of the source program instead of the machine language actually run by the hardware. As a final example, the text editor may be language specific, with commands which operate in terms of the syntax of the language being used, and mechanisms which allow syntax errors to be detected without leaving the editor to compile the program.