Monday, January 16, 2012

Registering Your Domain Name Is Easy

In order for the internet to work, domain names are essential. Your website cannot be easily found without a domain name. The domain name system (DNS) is used for converting human friendly names to IP addresses. A hostname or fully qualified domain name (FQDN), identifies a specific device within the DNS namespace, for example www.example.com identifies the device 'www' within the example.com domain.

Domain Registration Process

The process of claiming a domain name within the public DNS infrastructure is called domain name registration. It's a very simple procedure, costing very little these days. If you want to run a website a domain name is an essential prerequisite. There are many levels to the domain name system. A top level domain creates the basis of all internet registered domains. Top-level domains include:
  • .com
  • .org
  • .net
  • .co.uk
  • + many more.
Top level domains can have many secondary level domains, for instance domain1.com, where domain1 is this second level domain.

Nowadays there are numerous domain name extensions available for use. During the early days of the internet, there were just a few like .com, .net, .org, etc. Now many more extensions have become available, for example .me, .tv, etc., due to the huge increase in web sites being built.

Naming Conventions

There is a specific naming convention used for all domain names without exception. A domain name has the following restrictions:
  • Must use ASCII letters (A-Z and 0 to 9)
  • Maximum 255 characters in total.
  • Can include hyphens (-)
A domain tree is created by separating each level of the domain with a period (.) character.
Most domain names can be registered on a yearly cycle, but it is recommended that you register your domains for as many years as you can manage upfront. However, some domain extensions do not allow you to register on a yearly basis and demand that you pay for a minimum of two years registration in advance. One example of a domain extension that does apply this restriction is the .co.uk domain.
Computing devices use IP addresses, such a 192.168.0.1 to exchange data with one another, however, remembering these addresses is difficult for humans, so the Domain Naming System (DNS) converts human friendly names to IP addresses. There is another service for changing IP addresses to domain names, called reverse DNS (rDNS). The system is employed to match up IP addresses to domain names, i.e. the contrary of DNS.

Monday, January 9, 2012

Young Toddler Gets Verbal Abuse Out Of Apple Siri

The mother of a 10-year-old youngster from Coventry has been expressing her shock following having a demonstration unit of Apple’s iPhone 4S swear at her son.

Local Tesco

Kim Le Quesne informed the Coventry Telegraph that her child Charlie was out shopping with his dad in a local branch of Tesco, discovered the device in a showcase and asked the Siri personal helper application what number of people there were on the planet. The product answered by telling the lad that it wasn’t sure exactly what he was saying, and telling him to "Shut the f*** up, you ugly t***."
"It's verbal abuse," Mrs Le Quesne claimed. "We can’t believe the filth it came out with. He showed my husband what the phone had said to him and my husband found the store manager and said "it shouldn’t be saying that."

Sent For Diagnostics

Tesco stated the gadget will be shipped away to Apple for diagnostics, however it appears likely that some merry prankster had modified the login name on the unit to the offending seven words, so the mobile phone would default to the sentence regardless of the question. Apple is unavailable for comment during the holiday period.

Phone Still On Display

Mrs Le Quesne told the paper the woman's child went back to the retailer the next day and saw the exact same phone seemed to be still on the display case. The newspaper doesn't say whether the poor lad felt abused, or instead tried it again and dissolved in to fits of giggles.

Thursday, January 5, 2012

Installing Linux Server Modules Within The Command Line

The task of adding Linux kernel modules is a vital task for any Linux server system administrator. This article will provide a basis to understand the concepts and tools concerned. There are a number of terms used to refer to these modules, the formal phrase being "loadable kernel modules". However, you will commonly see them referred to as "modules" or "kernel modules".

Modular Kernel

The modern day Linux kernel uses a modular model allowing users to add additional functionality to the core of the operating system as and when required. In other operating systems a monolithic kernel model is used, requiring all functionality to be compiled into the kernel prior to this system being booted. In the past a monolithic kernel was preferred, as it is more efficient with regards the usage of memory resources, however nowadays most computers have multiple gigabytes of RAM available, so this is less of an issue. Being able to dynamically load kernel modules when required far outweighs any disadvantages of using slightly more memory.

So what is a kernel module? A kernel module is similar to a windows driver. A module will more often than not, provide software to handle a specific hardware device or type of device. Examples include:
  • video adapters
  • providing access to hard drives
  • DVD players
  • serial devices

Linux Kernel Tools

It is normal for kernel modules to be loaded at boot time, however due to their dynamic nature they can also be loaded at any time. A number of commands are available to the administrator for loading, unloading and finding out further information about a module.
The simplest commands for loading and unloading modules consist of "insmod" and "rmmod". The insmod command inserts a module in to the kernel, the rmmod command removes a module from your kernel. You will find a number of other commands which can be useful to understand when dealing with kernel modules. These are:
  • lsmod - lists all currently loaded modules
  • depmod - determine any dependencies a module has
  • modinfo - displays the .modinfo section of the module object file (i.e. a file with a .ko or .o file)
It is important hat to have a thorough understanding of each of the above commands when loading and unloading kernel modules. The modinfo command provides detailed information about the module, such as the kernel version that the module was compiled for, which can be critical when troubleshooting any problems found when attempting to load a kernel module. A higher level module administration command exists for dealing with kernel modules. It is:
  • modprobe - intelligently inserts or removes a Linux kernel module and all dependencies.
The modprobe command is basically a wrapper around insmod, rmmod and depmod, providing a single, user-friendly command. It is recommended for you to look at the help manual for modprobe if you're thinking of doing any work with loading or unloading Linux kernel modules.

Linux kernel modules are typically found under /lib/modules/[kernel-version] where by [kernel-version] is the kernel version number you are looking at. It is likely that you will see many different kernel versions in this directory and you should ensure that any modules you compile are placed in the directory matching to the kernel version you are doing work on.