To provide an inexpensive and compact system with high versatility by centralized processing the network system using a distributed processing and LAN by means of client/server by parallel CPU boards in one computer and sharing a distributed processing function.

The plural CPU boards and hard disks are stored in one unit (computer main body) and a simple various types communication method connecting the unit with the input/output devices of a keyboard, a display and a printer is provided. A function similar to the computer constructed by conventional LAN is provided. A floppy drive, a CD-ROM drive and a MODEM device are basically shared by one unit. Although only one computer exists, data processings can be realized in plural input devices (keyboards) and the function similar to the construction of a LAN system is provided by sharing the plural hard disks.