Soma: Created page with "==Video== The video for the lecture given on April 3, 2019 is now available: [https://homeostasis.scs.carleton.ca/~soma/os-2019w/lectures/comp3000-2019w-lec22-20190403-1.m4v..."

2019-04-04T01:11:29Z

Created page with "==Video== The video for the lecture given on April 3, 2019 is now available: [https://homeostasis.scs.carleton.ca/~soma/os-2019w/lectures/comp3000-2019w-lec22-20190403-1.m4v..."

New page

==Video==

The video for the lecture given on April 3, 2019 is now available: [https://homeostasis.scs.carleton.ca/~soma/os-2019w/lectures/comp3000-2019w-lec22-20190403-1.m4v Part 1], [https://homeostasis.scs.carleton.ca/~soma/os-2019w/lectures/comp3000-2019w-lec22-20190403-2.m4v Part 2].

==Notes==

<pre>
Lecture 22
----------

Atomic operations
Networking
hardware virtualization

Atomic operations
-----------------

atom means "indivisible" in the original greek?

an atomic operation is thus indivisible
- it completes or it doesn't happen

a transaction is a simulation of an atomic operation
- if parts of the transaction fail, you undo everything

Hardware virtualization
-----------------------
want to run multiple operating systems on one system
- so multiple kernels

But kernels are special. They expect access to:
- hardware-level interrupts
- run in supervisor mode
- devices
- page tables
- software interrupts (system call invocations)

Two strategies:
- fake it (emulation)
- to make it fast, just emulate the privileged operations
- original strategy of vmware on x86

- hardware virtualizes resources
- hypervisor mode over supervisor mode (ring -1)
- shadow page tables (virtualization of page tables)
- devices are faked or do their own virtualization
</pre>

Operating Systems 2019W Lecture 22 - Revision history

Soma: Created page with "==Video== The video for the lecture given on April 3, 2019 is now available: [https://homeostasis.scs.carleton.ca/~soma/os-2019w/lectures/comp3000-2019w-lec22-20190403-1.m4v..."