NOS (Network Operating System) is a discontinued operating system with time-sharing capabilities, written by Control Data Corporation in the 1970s. NOS ran on the 60-bit CDC 6000 series of mainframe computers and their successors. NOS replaced the earlier CDC Kronos operating system of the 1970s. NOS was intended to be the sole operating system for all CDC machines, a fact CDC promoted heavily. NOS was replaced with NOS/VE on the 64-bit Cyber-180 systems in the mid-1980s. Version 1 of NOS continued to be updated until about 1981; NOS version 2 was released early 1982. Time-sharing commands ACCESS – selects the access subsystem APL – selects APL programing language ASCII – select fill 128-character ASCII ATTACH – links to a permanent file AUTO – automatically generate five-digit line numbers BASIC – selects BASIC system BATCH – selects the batch system BEGIN – starts processing of CCL procedure (control language file) BINARY – selects binary input mode BRIEF – suppresses headers BYE – log off the system CALL – starts processing KCL procedure file (control language before CCL) CATLIST – lists user's permanent files CHANGE – changes parameters of a permanent file CHARGE – set charge number and project number CLEAR – releases all local files CONVERT – converts character sets (CR) – Carriage Return – requests terminal status if it is the first thing on a line CSET – selects the terminal character-set mode DAYFILE – lists a record of the user's activity DEBUG – activates or terminates CYBER interactive Debug DEFINE – create a direct-access permanent file DIAL – sends a one-line message to another terminal EDIT – Selects the text editor ENQUIRE – Requests the current job status EXECUTE – selects the Execute subsystem FORTRAN – selects the FORTRAN subsystem (FORTRAN 5) FTNTS – Selects the FORTRAN Extended Version 4 compiler (CDC's enhanced version of FORTRAN 4) FULL – Selects full-duplex mode GET – gets a copy of a permanent file GOODBYE – same as BYE HALF – clears full-duplex mode HELLO – logs out and starts login HELP – gets descriptions of NOS commands LENGTH – requests the length of a file LIB – get a copy of a permanent file LIMITS – lists the user's limits LIST – lists the contents of a file LNH – same as LIST except no headers LOGIN – same as HELLO LOGOUT – same as BYE MONITOR – connects to a