A computer system having a host computer and multiple terminals. The host computer (including any peripheral hubs or the like) has groups of at least three I/O ports (preferably USB ports) where the I/O ports of a single group are supposed to be used to connect I/O devices associated with a single terminal. When connecting up a new terminal, after a user connects two I/O devices into a group and affirmatively indicates, by user input, that these belong to the same terminal, then further devices subsequently connected into the same group of I/O ports will be automatically assigned to the terminal previously indicated by the user. Also, a computer system where multiple operating systems are respectively used to control multiple displays. A video output module creates a master frame display including display data for (at least) the displays of all of the operating systems. The master frame display is split into portions respectively corresponding to each operating system.