Pdf Operating System Lecture 01 Key Notes Doom. operating system. hardware: cpu, memory and devices. makes hardware useful to the programmer. usually: provides abstractions for applications. manages and hides details of hardware. . accesses hardware through low level interfaces unavailable to applications. . • a system can typically be in one of several contexts • user level – running an application • kernel process context running kernel code on behalf of a particular process e.g., performing system call also exception (mem. fault, numeric exception, etc.) or executing a kernel only process (e.g., network file server).
Lecture 2 Processes Part 1 Operating System Concepts Process: a running program. os creates and manages processes. each process has the illusion of having the complete cpu, i.e., os. virtualizes cpu. timeshares cpu between processes. enables coordination between processes. os manages the memory of the process: code, data, stack, heap etc. each process thinks it has a dedicated memory space for. On class: cs111acs111a is an extra 1 unit “pathfinders” or “ace” section for undergraduates with additional course support, practice. meets for an additional weekly section and has additional review sessions. section tues thurs 10:30 11:50am in 160 124. Lecture schedule •week 1 •introduction to operating systems, computer system structures, operating system structures •week 2 •processes and threads •week 3 •processes and threads, and cpu scheduling •week 4 •scheduling •week 5 •process synchronization 9. Solutions: – cpu preemption. * give application something, can always take it away (via clock interrupts) – dual mode operation. * when in the os, can do anything (kernel mode) * when in a user program, restricted to only touching that program’s memory (user mode) – interposition. * os between application and “stuff”.
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