File Access Operations affecting a file as a whole. (delete files, rename, truncate, etc.)

File filtering and processing Methods of filtering and processing files. (character translation, comparison, search, sort, word counts, etc.)

File Access Limits - Limiting access to files (permissions, locking, et al)

Stdio Stream file operations Buffered access of files and devices. fopen, fputc, fgetc, et al.

Low level file and device operations Unbuffered access of files and devices. (ioctl, fcntl, /dev, et al)

Text Editors and Word Processors

Data Compression

Directory Access Accessing directories of files, browsing, management, et al.

File Information Obtaining file information (status, configuration, et al)

File System Operations Operations for entire file-systems (quotas, configuration, consistency, mount, unmount, et al)

Specific Types of File Systems - Specific forms of file systems. DFS, NFS, MS-DOS, etc.

Local Process Communication - Communication between processes running on the same system. Synchronization. File locking. Signals. FIFOs, pipes, et al

Remote Process Communication - Methods of communicating to remote processes. Remote Procedure Calls, sockets, data format translation, et al

Terminal I/O - TTY (character based display and keyboard) and related routines.

File and Version Management RCS, CVS, distribution, etc.

File Transfer and Distribution - Protocols and Methods of transfering files and directories, distributing and installing software. (file collections and archives, FTP, cvsup, NFS, et al.)

Data integrity and Security, Checksums and Digests - cryptography, message digests, etc.