An interface providing portability for operating system kernels: the BIGSAM ideal machine

The design of a kernel/machine interface, which provides portability for an operating system kernel, and its implementation in the BIGSAM distributed operating system are discussed. The interface, consisting mostly of a set of procedure calls and the routines that implement them, provides an abstract or ideal machine on which the rest of the kernel runs. The basic concept of an ideal machine and its rationale as an aid to application and system portability is presented. Tradeoffs in designing an ideal machine and the principal areas of the interface are discussed. This is followed by a detailed examination of the three principal sets of ideal machine interfaces: ideal devices, ideal memory management and other ideal machine interfaces which include process/processor management and handling of system calls, interrupts and exceptions. The current status of the BIGSAM ideal machine is given