Courses/Computer Science/CPSC 457.F2013/Lecture Notes/WhatOS

What is an Operating System ?

In this session, we draw and discuss the boxes and arrows view of what an operating system is and contemplate the artificial split between userland and kernelspace.

So far, we have made some gentle progress on seemingly unrelated ideas:

• the command line (observing all the processes on a machine with 'ps aux' or 'top'
• observing program source code becoming a binary
• understanding the idea of time-multiplexing of the CPU

In this session, we will try to understand what the role of the OS is in managing a core OS abstraction: the idea of a process. Exactly what a process is and how it is created will be discussed in the next few sessions. We will take a look at LXR, which is a tool for "navigating" the linux source code.

• https://www.kernel.org/
• http://lxr.cpsc.ucalgary.ca/lxr/#linux/

Slides

• http://www.cpsc.ucalgary.ca/~locasto/teaching/2013/CPSC457-Fall/talks/whatos.pdf

Scribe Notes

• s1
• s2
• s3

Readings

• LKD Chapter 1