PURPOSE: To eliminate the futile cost and an extra space for a virtual computer system by sharing an SYSOUT writer, an SYSOUT management table, a data management part, and an input/output management part with plural virtual computer operating systems in a system shared address space.

CONSTITUTION: The coincidence is secured between the address spaces formed among an SYSOUT writer means, an SYSOUT input/output means, a print means, an input/output management means, and an SYSOUT management table which are provided in an operating system 2 and the address spaces formed among an SYSOUT writer means, an SYSOUT input/output means, a print means, an input/output management means, and an SYSOUT table which are provided in an operating system 3. In such a constitution, an SYSOUT writer means 5, an SYSOUT management table 6, a data management part 7, and an input/output management part 8 can be shared among both systems 2 and 3.