Linux Kernel Mailing List FAQ

One page I had not noticed, and which seems to contain lots of interesting features: the Linux Kernel Mailing List FAQ. There are some nice infos for newbies... But not so much information except a lot of very nice pointers to different useful places.

Linux Kernel: Copy on Write

Copy on Write is an important technique in the linux kernel memory management. The basic idea is to prevent the creation of unnecessary copies of structures when creating new processes. For this, when a child process is created, the kernel first provides only readable access to both parent and son. If one of the process need writable access, at the time it needs to write data in memory, the kernel throws a page fault indicating that a new copy should be created for the asking process. Thus, the data is actually copied only when the process actually tries to write.

Some information is of course available on Wikipedia on the Copy on Write page. Note that there is an acronym COW for Copy on Write.

Memory Management Documentation in Linux Kernel

As I was looking at the kernel newbies info. I found this post from Mel Gorman about documentation for the Memory Management under Linux. It contains links to two documents:

• Understanding The Linux Virtual Memory Manager
• Code Commentary On The Linux Virtual Memory Manager

Customer orientation

customer orientation is the regular acquisition of the wishes, needs and expectation of customers as well as their realization in products, services and interactive processes. The purpose is to ensure stable, reasonably economic relations with the clients. Two levels:

• Information level (what do we know of customers, which information collected, how are they organized, and how can they be used in processes: marketing, production..)
• Customer level
  • quality of products,
  • of services,
  • flexibility of services realization,
• qualification of salesperson as well as their
  • flexibility,
  • reliability and
  • friendliness,
• treatment of
  • sales
  • complaints
• interaction between customers and employees

Success formulas:

• personal interaction with customer
• knowledge of the customer (needs, expectation, desires)
• check customer satisfaction
• problem solving suggestions
• customer oriented organization
• customer oriented employees

Online C++ Documentation

I found a nice page as a C++ documentation: http://www.cplusplus.com/reference/.

C library

A number of headers are present in the standard C++ library, for example:

• asserts
• types
• errors
• floats
• Standard definitions
• localization
• limits of standard types
• maths
• C I/O library functions
• C strings
• C time
• C standard libraries
• Jump routines to preserve calling properties and environment ***
• and handling of variable arguments

I/O Streams

There is a number of headers existing for the C++ stream operations as well as a number of possible classes for all these headers information. The main reference page has a nice picture summarizing the relationship between these classes.

string header

The string headers is useful to represent characters sequence. It contains a number of operations which are described on a special page for the string operation topics. A nice aspect is also that these pages have examples. So it's quite nice to learn how to use them correctly.

Standard Template Libraries

One of the nice aspect of this page was for example the page on the Standard Template Library. It presents all the complexities of the different operation on the diverese containers which can be used with these structures. Dividing the different containers in three groups: sequence containers, container adapters and associative containers.

<algorithm>

But there is also one I was not aware of: the algorithm header, which provides a number of standard algorithms which are designed to work on ranges of elements. For example, it contains search, merge, sorting, heap, min/max as well as operation to modify sequences and structures (swapping, copying, partitioning).

Supplementary headers

There are 4 other headers which do not belong to the other above categories:

• functional
• iterator
• memory
• utility

Spanning Tree Protocol

Today I read the Linux Networking book, and learnr about bridging and the Spanning Tree Protocol which is used to improve communication in LANs by bridging different atomic LANs together. The idea behind this protocol is that some computer is chosen as the root of the network and a spanning tree is built to optimize creation of the spanning tree and to prevent loops to be created in the network. This protocol which has an IEEE specification has also two other successors: the Rapid Spanning Tree protocol and the Multiple Spanning Tree Protocol. I will probably update this entry in order to give an overview of the details of these protocols.

Personal Projects

Here is a list of personal pet technical projects I have:

• Web 2.0 gallery
• data mining web site
• data mining experiments
• data warehousing
• information extraction tool
• ontology learning
• linux kernel learning
• inference engine technology
• fca implementation
• database implementation aspects

Each of these project is already in some kind of planing or development stage.

Open Data Sources - presented By UK Governement

The U.K has set a number of interesting data sources for free use in order to ease the development of new tools. These data sources are found there.

Lguest - simple virtualization mechanism

From the article at LWN.net, I learnt that there is a small virtualisation framework for linux using an hypervisor: lguest. This virtualization framework allows the testing of drivers. So I should use this to test some kernel changes which might be problematic.

Weka Online

It seems that there is now the possibility to use Data Mining online using Weka. A company, CEO delegates, has built a web site where some arff files can be loaded as well as the corresponding data mining algorithms chosen.

It was actually partly one of the things I planed to do. But there are still lots of supplementary things which can be done. So let's see what happens.