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Ininformation technology,bare machine (orbare-metal computer) is acomputer which has nooperating system.[1] The software executed by a bare machine, commonly called a "bare metal program" or "bare metal application",[2] is designed to interact directly with hardware. Bare machines are widely used inembedded systems, particularly in cases where resources are limited or high performance is required.[3]
Typically, a bare-metal application will run faster, use less memory and be more power efficient than an equivalent program that relies on an operating system, due to the inherent overhead imposed by system calls. For example, hardware inputs and outputs are directly accessible to bare metal software, whereas they must be accessed through system calls when using an OS.[4]
Bare metal applications typically require more effort to develop because operating system services such as memory management and task scheduling are not available.
Debugging a bare-metal program may be complicated by factors such as:
Bare-metal programming is generally done using a close-to-hardware language such asRust,C++,C, orassembly language.[5]
Early computers, such as thePDP-11, allowed programmers to load a program, supplied inmachine code, toRAM. The resulting operation of the program could be monitored bylights, and output derived frommagnetic tape, print devices, orstorage.
Bare machine programming is a common practice inembedded systems, in whichmicrocontrollers ormicroprocessors boot directly into monolithic, single-purpose software without loading an operating system. Suchembedded software can vary in structure. For example, one such program paradigm, known as "foreground-background" or "superloop" architecture, consists of an infinitemain loop in which each task is executed sequentially.[6]