COMP 310 Lecture 1: Notes

• School: McGill University
• Department: Computer Science (Sci)
• Course: COMP 310
• Professor: Rola Harmouche

Document Summary

Based on professor"s comp 310 lecture slides, with additions and clarifications by author. Some elements from textbook or allan wang"s website. What is an operating system: trusted software interposed between the hardware and application/utilities to improve efficiency and usability, needs to be protected. Interposed between hardware and applications: most computing systems have some form of operating system, hard to use computer systems without os. Main idea of computer: read input, process output, process jobs. In the beginning : computers cost millions of , hard to operate (done using console switches, hard to program particularly device i/o, every second counts! Expensive machines cannot idle utilization should be very high. Idea: minimize computer idle time: batch processing was devised, programming done offline and subroutine were created for common tasks. I/o and processing overlap obtained via buffering and interrupts. 1: cost of computers (i. e. : computer time, cost of people (i. e. : user time)