System programming language
A system programming language is a programming language used for system programming; such languages are designed for writing system software, which usually requires different development approaches when compared with application software. Edsger Dijkstra referred to these languages as machine oriented high order languages, or mohol.
General-purpose programming languages tend to focus on generic features to allow programs written in the language to use the same code on different computing platforms. Examples of such languages include ALGOL and Pascal. This generic quality typically comes at the cost of denying direct access to the machine's internal workings, and this often has negative effects on performance.
System languages, in contrast, are designed not for compatibility, but for performance and ease of access to the underlying computer hardware while still providing high-level programming concepts like structured programming. Examples include Executive Systems Problem Oriented Language (ESPOL) and Systems Programming Language (SPL), both of which are ALGOL-like in syntax but tuned to their respective platforms. Others are cross-platform software, but designed to work close to the hardware, like BLISS, JOVIAL, and BCPL.
Some languages straddle the system and application domains, bridging the gap between these uses. The canonical example is C, which is used widely for both system and application programming. PL/I was an early example. Some modern languages also do this such as Rust and Swift.