CS 1550 Lecture 2: CS 1550 Scheduling
Document Summary
Only way to truly run programs simultaneously, in parallel, is with multiple cpus. Cpu can run billions of instructions per second: enough to run processes in pseudo parallel. Contains items needed for process management, file management, and memory management. Can communicate without use of os (through their address space) Cooperative work & sharing information: webserver. Depends on what we want: isolation or cooperation. User threads vs. kernel threads: os choice (pthread library is a layer on top of this choice. Meant to protect user from caring how the os chooses: modern os, hybrid: implement kernel threading. Need the option of kernel threading: pthread in both, but the implementation is different for each. Abstraction is supposed to hide the implementation. Insert pthread yields no matter what: kernel. Os has full support for every thread operation (creating and managing) Scanf blocked issue: without support from os this is unsolvable. We want a way to side step blocking (non-blocking syscall: change scanf implementation.
