mVSiy‖Opening and Closing Files
UxFz9‖Closes a specified file that was opened with the Open statement.
jM79E‖Returns the next available file number for opening a file. Use this function to open a file using a file number that is not already in use by a currently open file.
Etqck‖Opens a data channel.
iLCKn‖Closes all open files and writes the contents of all file buffers to the harddisk.