354 Chapter 11 File Systems and Directories available for use), and for each directory, it maintains a table that records information about the files in that directory. To create a file, the operating system finds free space in the file system for the file content, puts an entry for the file in the appropriate directory table, and records the name and location of the file. To delete a file, the operating system indicates that the memory space the file was using is now free, and the appropriate entry in the directory table is removed. Most operating systems require that a file be opened before read and write operations are performed on it. The operating system maintains a small table of all currently open files to avoid having to search for the file in the large file system every time a subsequent operation is performed. To close the file when it is no longer in active use, the operating system removes the entry in the open file table. At any point in time, an open file has a current file pointer (an address)
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