This book provides a complete introduction to system software including coverage of assemblers, loaders, linkers, macro prossesors, compilers and operating systems. A central theme of the book is the relationship between system software and the architecture of the machine it is designed to support. The book first presents th fundamental concepts and basic design of each type of software in a machineindependent extensions to the basic concept and gives examples of actual system software. A hypothetical machine, the Simplified instructional (SIC), is used to present the fundamental funetions of each piece of solftware.