What is a file management block?

File control block (FCB), also called descriptor of the file, is the type of data structure that is temporarily assigned by a computer operating system to maintain the status of the created or otherwise manipulated data file. In most cases, to store basic information about the file, such as the name, extension and location on logical unity, and dynamic information, such as the current address within, within most instances, the file control block is used in most instances. Originally, the file control block has been a very well -defined structure in some operating systems, but since then it has become a more general term for a structure used to monitor the actively processed file. One important purpose of file control block is to help file system system to monitor the state of the file to avoid different operations in an attempt to edit a file of contradictory ways, such as reading from the file to which it is currently registered. The structure is not turned onBut for data files, it can also be used to monitor address information information, although the data structure is usually shortened to remove unnecessary fields because the directory cannot contain data.

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two operating systems, namely the Microsoft® (MS-DOS) disk system (MS-DOS) and the microprocessors control program (CP/M), were the first operating systems to use file controls to manage files. These systems used very similar structures to help manage the files to which it was accessible. When other operating systems and file systems have been developed, the concept of file control block remained, but the implementation changed and the data structure was very different from one system to another. Most of the computer operating systems used in 2011 use some form of file control, especially when using your own file systems for removable hardware,Although the structure of the data is used, it is not compatible with earlier versions without emulation and is generally larger and hidden from most programming applications at a high level.

General, file control block contains information that can be changed while using a file by the operating system. In addition to the name and location, memory indicators are kept on different points in the file itself. This allows sequential reading and writing, as well as reading and writing random access when paired with a variable in FCB, which stores the size of random access. File permissions are also monitored, such as reading or executable file status. The use of FCB also provides a mechanism that prevents two or more processes in operation on the same file unpredictable as an attempt to connect information to the end of the file, while the same file is copied to another location.