CS3 Operating Systems 2013-14, Practical Exercise.

PHASE 1
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Background reading
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First, you should find some general descriptions of the Linux
kernel. Many such descriptions may go into more detail than we have so
far covered in the course; however, we have reviewed the high-level
structure of OSes, which should suffice. At this stage, you can ignore
more detailed descriptions of virtual memory structures, etc.,
although you are of course free to read up on this in advance of
lectures.

Warning: Linux is a rapidly evolving system. In this exercise, you
will be using kernel 2.6.21.1. This is older than the kernel now
running on DICE; we're using an older kernel because some of the
things we rely on have been locked down in new kernels. 
(In Linux kernel numbering, the second number is even for
production versions, and odd for development versions - 2.6 is the
current production series, but some people still use 2.4.)

Unfortunately, there is a shortage of good documentation about the 2.6
kernels. However, the basics have not undergone any really dramatic changes,
although many of the details have. Most high-level information and
quite a lot of detailed information about 2.4 or even
2.2 kernels can be (cautiously) applied to the 2.4 series.
Information about earlier releases should be carefully checked before
you assume it applies to modern kernels.

Suitable descriptions can be found OS textbooks that take Linux as a
case study. Stallings does not have a single chapter on Linux, but
several chapters contain sections on aspects of Linux: specifically
sections 2.7, 4.6, 8.4, 10.3. On the Stallings book website, there is
a PDF file collecting together all the Linux information. Silberschatz
has a chapter on Linux, of about the right level for this phase.

There are also many online resources, which are themselves sufficient.
The centre for Linux documentation is
    The Linux Documentation Project
    http://www.tldp.org/
You should look round this site, and consider particularly the
following items in the "Guides" section:

 + The Linux Users' Guide.
   This is a basic introduction to end-user use of Linux, covering
   such things as the use of the shell, etc. If you are not confident
   in traditional (i.e. command-line, not GUI) use of Linux, this
   guide may be useful. (Real system programmers don't use GUIs, of
   course.)

 + The Linux Kernel.
   Although this is very out-dated, it is probably the single most
   useful online resource (apart from the kernel source itself!). It
   provides a good description of the 2.0 kernel, and does not assume
   a great deal of pre-existing technical OS knowledge. You should
   read this document.

 + The Linux Kernel Hackers' Guide.
   This is more outdated, referring to the 1.0 and 1.1 releases.
   However, it may be useful in conjunction with other documents.

 + Linux Kernel 2.4 Internals
   This is the other main online resource. It provides quite detailed
   information on the implementation of the current kernel. It is
   written for a fairly expert audience, in a concise and unforgiving
   style. Note that the scheduler (which is the part we are most
   likely to look at) has been completely re-written between 2.4 and
   2.6 - hence ...

 + The Linux Kernel Module Programming Guide
   Since you're going to be writing a kernel module, it's well worth
   looking through this.

And from outside:   

 + Understanding the 2.6.8.1 Linux Scheduler 
   http://joshaas.net/linux/
   This is of course a bit out of date, but I don't think there are
   really serious scheduler changes between 2.6.8 and 2.6.21.


There are also several relevant HOWTOs. In particular:

 + The KernelAnalysis-HOWTO.
   This is a summary of the 2.4 kernel structure. Read it
   after reading the more leisurely "The Linux Kernel".

 + The Kernel-HOWTO.
   This describes the process of building the kernel. You will not be
   required to build a kernel, but it will do no harm to get an idea
   of what is involved.