Microkernel Operating Systems

Microkernel Operating Systems

Operating Systems

For a one-semester undergraduate course in operating systems for computer science, computer engineering, and electrical engineering majors. Winner of the 2009 Textbook Excellence Award from the Text and Academic Authors Association (TAA)! Operating Systems: Internals and Design Principles is a comprehensive and unified introduction to operating systems. By using several innovative tools, Stallings makes it possible to understand critical core concepts that can be fundamentally challenging. The new edition includes the implementation of web based animations to aid visual learners. At key points in the book, students are directed to view an animation and then are provided with assignments to alter the animation input and analyze the results. The concepts are then enhanced and supported by end-of-chapter case studies of UNIX, Linux and Windows Vista. These provide students with a solid understanding of the key mechanisms of modern operating systems and the types of design tradeoffs and decisions involved in OS design. Because they are embedded into the text as end of chapter material, students are able to apply them right at the point of discussion. This approach is equally useful as a basic reference and as an up-to-date survey of the state of the art.

A Zero Kernel Operating System

A secure kernel is the keystone upon which all software systems are built. Historically, memory corruption errors have accounted for a large portion of kernel bugs. These bugs are difficult to detect and avoid in memory-unsafe languages such as C. To mitigate such bugs, we build on top of an operating system written in a memory-safe language, Rust. Rust provides memory-safety guarantees while remaining as fast and flexible as other systems languages. Yet, some operations within operating systems, such as hand-written assembly for interrupt handling, do not fit within the scope of a language memory-safety model. To reduce the scope of these errors, microkernels isolate and reduce privilege by moving much of the traditional kernel into userspace services. However, their effectiveness is limited by the inflexibility of modern hardware. The Zero Kernel Operating System (ZKOS) emphasizes the high-level ideas of compartmentalization and least privileges on a tagged architecture. In particular, instead of relying on the Ring model and paging, which coarsely limit privilege and isolation granularity, a tagged architecture allows ZKOS to isolate at the memory word level and provide truly disjoint privileges. To this end, ZKOS slices kernelspace and userspace into fine-grained components based on function. Then, ZKOS defines specific entry and exit points between components and composes policies to limit component transitions and privileges. This increases the precision of isolation and privilege, and complements the local compile-time and runtime checks Rust performs to reduce the scope of bugs.