COMPSCI 377 Lecture Notes - Lecture 2: Parent Process, Child Process, Program Counter
17 Feb 2018
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Time sharing: the os runs one process, stops it, runs another one, etc. Policies: algorithms to ensure the best performance while switching processes. Changes data accessed or effected from the system during execution. How to handle interrupts e. g. displaying data on a monitor. Each os had its own design as there"s no perfect solution. Need to be flexible (portability and backwards compatibility) Reliable (small bugs could ruin the entire experience) Performance (user to kernel mode transfers are expensive) Tabs on a browser, databases, office apps, etc. + syscall is the parent process and it creates child processes. + createprocess() is very complex due to accounting for i/o, privilege, scheduling, etc. +create, destroy, wait, miscellaneous control (e. g. suspend/resume), and status functionalities. Load code and data to memory the address space of the process. Can be loaded eagerly (whole program) or lazily (only necessary pieces of code and data) Start the process by running the main routine.
