Bài giảng Hệ điều hành - Chapter 12: Operating System Design

Operating System Design Chapter 12 12.1 The nature of the design problem 12.2 Interface design 12.3 Implementation 12.4 Performance 12.5 Project management 12.6 Prends in operating system design Paradigms (1) Algorithmic code Paradigms (2) Event-driven code Implementation One possible design for a modern layered operating system Layer Naming Directories are used to map external names onto internal names Static Versus Dynamic Structures Code for searching the process table for a given PID. Searching a static table for a pid Hiding the Hardware (1) CPU-dependent conditional compilation Hiding the Hardware (2) Word-length dependent conditional compilation Space-Time Trade-offs (1) A procedure for counting bits in a byte (a) A procedure to count the 1 bits in a byte Space-Time Trade-offs (2) A macro to count the bits A macro to access bit count in a table (b) Macro to count the bytes (c) Macro to look up the count Space-Time Trade-offs (3) (a) Part of an uncompressed image with 24 bits per pixel (b) Same part compressed with GIF, 8 bits per pixel (c) The color palate Caching Part of an i-node cache Software team Structure Mills’ proposal for populating a 10-person chief programmer team The Role of Experience (1) Traditional software design progresses in stages The Role of Experience (2) Alternative design produces a working system that does nothing starting on day 1