1. An instrumentation system comprising: a computer; a plurality of instruments selectively controlled by input data and producing output data; bus means connecting said instruments to said computer for conveying input data and output data to and from selected instruments; a screen controlled by said computer; and software controlling operation of said computer implementing a plurality of virtual machines each comprising a set of computer instructions, said virtual machines being associated with respective ones of said instruments for providing input thereto or receiving output therefrom, a virtual machine controlling display on said screen of a virtual front panel depicting an instrument and able to display a representation of data associated with an instrument represented by a virtual front panel; said software further comprising: software responsive to operator input for enabling a selection of ones of said virtual front panels, said computer being responsive to said selection for generating a new virtual machine comprising a combined set of the computer instructions which comprises the virtual machines associated with the selection of ones of said virtual front panels, said new virtual machine controlling display of a new virtual front panel on said screen including representation of values conveyed on said bus with respect to instruments represented by said selection of ones of said virtual front panels, said new virtual machine initiating transmission of input data to one of said instruments in response to changes in values of input data represented by said new virtual front panel and for portraying an output data value as represented by the new virtual front panel in response to output data received from another one of said instruments.