Software for software

Let's start with the standard textbook definition first.

System programming (or systems programming) is the activity of programming computer system software. The primary distinguishing characteristic of system programming when compared to application programming is that application programming aims to produce software that provides services directly to the user (for example, a word processor), whereas system programming aims to produce software and software platforms that provide services to other software, and are designed to work in performance-constrained environments, for example, operating systems, computational science applications, game engines and AAA video games, industrial automation, and software as a service applications.

The definition highlights two main concepts of what system applications are as follows:

• Software that is used by other software, not directly by the final user.
• The software is hardware aware (it knows how the hardware works), and is oriented toward performance.

This makes it possible to easily recognize as system software operating system kernels, hardware drivers, compilers, and debuggers, and not as system software, a chat client, or a word processor.

Historically, system programs were created using Assembly and C. Then came the shells and the scripting languages that were used to tie together the functionality offered by system programs. Another characteristic of system languages was the control of the memory allocation.