When this form of the HELP command prints out these usage messages the fol- lowing conventions apply: number Compulsory numeric input string Compulsory input (often a filename) [number] Optional numeric input [string] Optional input These usage messages tell you what input formats are acceptable to 1616/OS command parser. Typing in commands which comply with this format will not cause a ‘syntax error’ message, however they may still be rejected by 1616/OS . More detailed help messages are given from Version 3.2c on, and this includes a full list of option parameters. Page 94 User Tutorial Manual 1616/OS Commands