Quick Reference Search Tool Webopedia Jobs Link to Us Advertising Tech Support Submit a URL Request a Term Report an Error Internet News Internet Investing Internet Technology Windows Internet Tech. The name of a file .
All files have names.
Different operating systems impose different restrictions on filenames. Most operating systems, for example, prohibit the use of certain characters in a filename and impose a limit on the length of a filename. In addition, many systems , including DOS and UNIX , allow a filename extension that consists of one or more characters following the proper filename. The filename extension usually indicates what type of file it is. Within a single directory , filenames must be unique.