Systems programming

Systems programming, or system programming, is the activity of programming

Systems programming requires a great degree of hardware awareness. Its goal is to achieve efficient use of available resources, either because the software itself is performance critical or because even small efficiency improvements directly transform into significant savings of time or money.

Overview

The following attributes characterize systems programming:

• The programmer can make assumptions about the hardware and other properties of the system that the program runs on, and will often exploit those properties, for example by using an algorithm that is known to be efficient when used with specific hardware.
• Usually a low-level programming language or programming language dialect is used so that:
  • Programs can operate in resource-constrained environments
  • Programs can be efficient with little
    runtime overhead, possibly having either a small runtime library
    or none at all
  • Programs may use direct and "raw" control over memory access and control flow
  • The programmer may write parts of the program directly in assembly language
• Often systems programs cannot be run in a debugger. Running the program in a simulated environment can sometimes be used to reduce this problem.^{[dubious – discuss]}

In systems programming, often limited programming facilities are available. The use of

may have extremely elaborate logging subsystems.

Implementing certain parts in operating systems and networking requires systems programming, for example implementing paging (virtual memory) or a device driver for an operating system.

History

Originally systems programmers invariably wrote in

also has applications as a systems language. In the 1970s, C became widespread, aided by the growth of Unix. More recently a subset of C++ called Embedded C++ has seen some use, for instance it is used in the I/O Kit drivers of macOS.^[2] Engineers working at In 2015 Rust came out, a general-purpose programming language often used in systems programming. Rust was designed with memory safety in mind and to be as performant as C and C++.

Alternative meaning

For historical reasons, some organizations use the term systems programmer to describe a job function which would be more accurately termed

software products had substantial code contributions from customer programming staff. This type of programming is progressively less common, and increasingly done in C rather than Assembly, but the term systems programmer is still used as the de-facto job title for staff administering IBM mainframes even in cases where they do not regularly engage in systems programming activities.

See also

• Ousterhout's dichotomy
• System programming language
• Scripting language
• Interrupt handler
• Computer Programming

References

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Further reading

• Systems Programming by John J. Donovan