Abstract: System isolation is a key enabling technology for reliability and scalability of computer system. Traditional system isolation is based on privilege layering, which is known as “layered isolation model”. Software is divided into different layers, the lower layer has the higher privilege, which is responsible for the isolation of up-layer software. Recently, as new hardware extensions keep evolving, including hardware assisted virtualization, ARM TrustZone, Intel SGX (Software Guard Extension), a new model, named “disaggregated isolation model”, is becoming a hot research topic, which brings new opportunities and challenges to traditional system software.

Key words: isolation, operating system, virtualization, hardware security extension