7 : Multiple choice Digital devices usually use () number system to represent digital data. (1.0) A. Octal B. Binary C. Hexadecimal D. Decimal A O B O C O DA file cabinet or tree metaphor represents () helps the user to visualize the organization of computer files. (1.05 ) A. System operating model B. Disk management model C. Physical storage model D. Logical storage model A B O D9 : Multiple choice The () network establishes a dedicated connection between two devices, while the () network can divide messages into smaller packets and process them on a "first come, first served" basis. (1.05) A. packet-switched, circuit-switching B. satelite-switching, packet-switching C. packet-switching, TV-switching D. circuit switching, packet switching.