Auto-hébergement (informatique)

In computer programming, self-hosting is the use of a program as part of the toolchain or operating system that produces new versions of that same program—for example, a compiler that can compile its own source code. Self-hosting software is commonplace on personal computers and larger systems. Other programs that are typically self-hosting include kernels, assemblers, command-line interpreters and revision control software. An operating system is self-hosted when the toolchain to build the operating system runs on that same operating system. For example, Windows can be built on a computer running Windows. Before a system can become self-hosted, another system is needed to develop it until it reaches a stage where self-hosting is possible. When developing for a new computer or operating system, a system to run the development software is needed, but development software used to write and build the operating system is also necessary. This is called a bootstrapping problem or, more generically, a chicken or the egg dilemma. A solution to this problem is the cross compiler (or cross assembler when working with assembly language). A cross compiler allows source code on one platform to be compiled for a different machine or operating system, making it possible to create an operating system for a machine for which a self-hosting compiler does not yet exist. Once written, software can be deployed to the target system using means such as an EPROM, floppy diskette, flash memory (such as a USB thumb drive), or JTAG device. This is similar to the method used to write software for gaming consoles or for handheld devices like cellular phones or tablets, which do not host their own development tools. Once the system is mature enough to compile its own code, the cross-development dependency ends. At this point, an operating system is said to be self-hosted. Software development using compiler or interpreters can also be self hosted when the compiler is capable of compiling itself.