Computers 3 Maintenance and repair 3 Microcomputers -- 3 Computer storage devices 2 Sound -- 2 Computer input - output equipment 1 Computer input and output equiment 1 Handbooks, manuals,etc 1 Handbooks,manual,etc 1 Internet working (Telecommunication) 1 Local area network(Computer network) 1 Operating system (computers) 1 Operating systems (Computers) 1 Recording and reproducing -- 1 Software configuration management 1 Wide are networks (Computer networks) 1 Wide area networks (computer networks) 1 recording and reproducing -- 1