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In electronic systems and computing, firmware is a type of software that provides control, monitoring and data manipulation of engineered products and systems. Typical examples of devices containing firmware are embedded systems (such as traffic lights, consumer appliances, and digital watches), computers, computer peripherals, mobile phones, and digital cameras. The firmware contained in these devices provides the low-level control program for the device. As of 2013, most firmware can be updated. Firmware is held in non-volatile memory devices such as ROM, EPROM, or flash memory. Changing the firmware of a device may rarely or never be done during its economic lifetime; some firmware memory devices are permanently installed and cannot be changed after manufacture. Common reasons for updating firmware include fixing bugs or adding features to the device. This may require ROM integrated circuits to be physically replaced, or flash memory to be reprogrammed through a special procedure. Firmware such as the ROM BIOS of a personal computer may contain only elementary basic functions of a device and may only provide services to higher-level software. Firmware such as the program of an embedded system may be the only program that will run on the system and provide all of its functions. Before integrated circuits, other firmware devices included a discrete semiconductor diode matrix. The Apollo guidance computer had firmware consisting of a specially manufactured core memory plane, called "core rope memory", where data were stored by physically threading wires through (1) or around (0) the core storing each data bit. == History == Ascher Opler coined the term "firmware" in a 1967 ''Datamation'' article.〔 〕 Originally, it meant the contents of a writable control store (a small specialized high speed memory), containing microcode that defined and implemented the computer's instruction set, and that could be reloaded to specialize or modify the instructions that the central processing unit (CPU) could execute. As originally used, firmware contrasted with hardware (the CPU itself) and software (normal instructions executing on a CPU). It was not composed of CPU machine instructions, but of lower-level microcode involved in the implementation of machine instructions. It existed on the boundary between hardware and software; thus the name "firmware". Over time, popular usage extended the word "firmware" to denote anything ROM-resident, including processor machine instructions for BIOS, bootstrap loaders, or specialized applications. Until the mid-1990s, updating firmware typically involved replacing a storage medium containing firmware, usually a socketed ROM integrated circuit. Flash memory allows firmware to be updated without physically removing an integrated circuit from the system. An error during the update process may make the device non-functional, or "bricked", which the system is vulnerable to when the parts of flash storage containing the core software or update program are erased and reprogrammed. If the update process is interrupted abruptly, this core software may not be operational to run the device and retry the update, which can be avoided by having a protected read-only section of the flash storage that holds the core software. The downside for the manufacturer is that this read-only software cannot be corrected in the field, so it must be tested to a very high degree before the release. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「firmware」の詳細全文を読む スポンサード リンク
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