Realizing a virtual machine

Historically, microprogramming has been viewed as an emulation tool or a means of extending hardware instruction sets. This usually results in a piecemeal application of microprogramming techniques. The concept of a virtual machine, in which firmware realizes the complete functional structure of an idealized computer, is often debated but infrequently attempted. This paper examines microcoded interpretation of high-level languages and microcoded support of complex algorithms in a front-end peripheral processor as implemented for a commercial computer subsystem. The virtual machine and its supporting structure are outlined and specific advantages of microprogramming are discussed. Microprogramming is presented as a generalized systems resource.