An Analog/mixed signal automatic test system includes a software architecture that creates a virtual composite instruments through novel software dynamic allocation of low level resources. These virtual composite instruments provide backwards and forwards compatibility to a variety of automatic test equipment, known or available on the market. The virtual composite instruments are free from the normal constraints imposed by hardware implementations. Creation of the virtual composite instruments allows a single piece of automatic test equipment system to emulate many implementations of automatic test equipment, providing higher utilization, and therefore a lower cost test solution for device manufacturers. The test instruments are preferably object controls and are preferably instantiated and controlled by the test system server. This allows multiple users to control the tester simultaneously across, for example, the Internet.