Meaning of URL

URL stands for Uniform Resource Locator. It specifies the global address of web documents and web resources. The basic reason behind locating or identifying a resource on the web is access or communication. Interaction between web users and the Internet resources is possible, only if each resource on the Internet is identified in a standardized manner. A URL serves this purpose. Let’s look at the different parts that compose it and what purpose each of them serves.
The first part of the address is the protocol identifier. HTTP and FTP are examples of protocol identifiers, which indicate the protocol in use. More rightly known as the scheme, this part of the URL denotes how to connect to the web resource. It is not case-sensitive but the canonical form is lowercase.
The second part of a URL is the resource name that comprises the IP address or the domain name of the web resource. It denotes where to connect. The domain name may be followed by a port number which is separated by a colon. When specified, a connection to that port number is established. If the port is not specified, the browser connects to the default http port which is 80.
The domain name may be followed by a path when a particular resource such as a file or a page needs to be retrieved. This part of the URL specifies what to retrieve. It is case-sensitive. On servers based on Microsoft, it is not. A URL may consist of a fragment identifier which denotes a specific location on the page. If it is a part of the URL, the browser displays that specified part of the page.
A uniform resource locator is synonymous with uniform resource identifier that is abbreviated as URI. By definition, URI is a string of characters that is used to identify resources on the Internet. Either it is the uniform resource locator or a uniform resource name (URN).
Typically, HTTP is the first part of a URL. As you know, it is the protocol identifier. It is followed by a colon and two forward slashes after which comes the domain name of the resource to be located. URLs are commonly referred to as website addresses. To reach any particular website, you need to type its URL in the address bar of your browser, which then retrieves the desired page for you.
An internationalized resource identifier (IRI) is a type of URL that includes Unicode characters. It allows one to create URLs using one’s local alphabet. The domain name is known as an internationalized domain name (IDN). It is converted into punycode, wherein Unicode characters are represented as ASCII characters that DNS supports. When a user specifies a URL in the local alphabet, it is converted to Unicode, and characters that are not a part of the URL character set are converted to English letters using percent-encoding.
Tim Berners-Lee and the URI working group of the Internet Engineering Task Force (IETF) standardized the Uniform Resource Locator in 1994. The Domain Name System created in 1985 was combined with the file path syntax.
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Open Source Software Examples

There are three major types of software – Programming Software, Systems Software and Application Software. Of the three, the latter two come in two broad classifications – open source and closed source. There are many different types of application software which are open source and most of us regularly download and use them on our PC/laptop, such as VLC. In this Buzzle article, we will take a look at some popular and highly recommended open source software examples for different types of operating systems.

An open source computer software is either a systems software or an application software that is available freely in the form of source codes and the users are permitted, under the software license, to study, modify and improve the software. The Open Source Initiative has set certain parameters to determine whether a software license renders the software open source or not. These parameters are very specific and are as laid down below. In order to be considered Open Source, a software must qualify on all of these parameters.

Parameter Elaboration
Free Redistribution The software license does not restrict anyone from selling or giving away the software as part of a software package which contains programs from various other sources. The license also should not require any royalty or fee for such sale or passing over of the software.
Source Code The program should essentially contain source code and the distribution should be permitted in source code as well as compiled form. If the source code is not provided free, the means of obtaining it should be well publicized and should not cost more than a reasonable charge, though the preferred mode of obtaining such code should be free downloading via the Internet. Deliberate obfuscation of source code is not permitted and outputs of processors and translators are against the rule.
Derived Works The software license must permit modifications to the source code and the distribution of such derived work must be allowed to be distributed under the same terms as the original software license.
Integrity of Author’s Source Code Distribution of source code in modified form can be restricted by the license only if the license necessitates distribution of patch files with the source code for modification of the program at the time of writing it. In such case, the license must be explicit in allowing distribution of software which is developed from modified source code and may require derived works to be known by a different name or version number from the original.
No Discrimination of Persons or Groups There should be no discrimination, whatsoever, by the license against any person or user group. What is made available to one must be made available to everyone else.
No Discrimination Against Fields of Endeavor There should be no restriction on the use of the software for any field of work. If it is free for business use, it must also be free for use in lab researches.
Distribution of License The rights to the program should apply to everyone, to whom the program is redistributed without any necessity for applying for additional license by such parties.
License Must Not be Specific to a Product The rights attached to the program must not be specific to the software of which it is a part. Even if the program is extracted from that particular software package and used elsewhere within the program’s license terms, the user of such an isolated program would have the same rights as he would have had on using the program along with the original software distribution.
License Must Not Restrict Other Software There should be no restriction on any other software that is distributed along with the licensed software. The other software may or may not be open sourced but that should not put any restrictions on their distribution on the same medium as the open source one.
License Must be Technology Neutral No part of the license should weigh upon any particular technology or interface style.

VLC, Mozilla Firefox and MySQL are prominent software examples which are open source. Linux and Ubuntu are prominent examples of open source operating systems. Let us browse through some examples for two major operating systems – Windows and Mac.

Popular Open Source Software for Windows
Firefox ~ web browsing
Miro ~ video player, bittorrent, pod casting
Pidgin ~ instant messaging
Miro Video Converter ~ convert any video to mp4 or theora
SkipScreen ~ skip unnecessary clicks and waiting time on media sharing sites such as zShare
Thunderbird ~ e-mail
RSSOwl ~ cross platform RSS client
Cabos ~ easy peer-to-peer file sharing
Gnucleus ~ Gnutella search and file sharing software
VLC ~ plays Quicktime, AVI, DIVX, OGG and many other video/audio formats
Media Player Classic ~ plays lots of media formats
Open Office ~ word processing and spreadsheet functions aka MS Office
AbiWord ~ word processing
Juice ~ great pod casting client
Handbrake ~ convert/rip DVD to MPEG-4 format, one of the best DVD ripping software
Audacity ~ sound recording software
Gipm ~ graphics editing aka Photoshop ~ similar to Gimp
Inkscape ~ application for vector graphics
Filezilla ~ FTP application
X-Chat2 ~ IRC client
PealZip ~ extracting and archiving functions
ZScreen ~ open source application for screen-capture functions
Launchy ~ open source program launcher that works on keystrokes
AutoHotkey ~ open source short-cut creator which enables you to create keyboard shortcuts for just about any task that is of repetitive nature
Notable Open Source Software for Mac
Mozilla Firefox ~ web browsing
Miro ~ video playing, bittorrent, pod casting
Audium ~ instant messaging
Miro Video Converter ~ convert any video to mp4 or theora
Vienna ~ RSS client
Mozilla Thunderbird ~ e-mail
SolarSeek ~ file sharing client
Q Emulator ~ running Windows on Mac
Perian ~ plugin allowing quicktime for playing additional media formats
VLC ~ plays Quicktime, AVI, DIVX, OGG and many other video/audio formats
iPodDisk ~ iPod ripping
Burn ~ CD/DVD burner
Vidalia ~ user anonymity on the web
Bean ~ word processor
KisMac ~ wireless scanning on Mac
Xee ~ fast image browsing and viewing
Scribus ~ DTP application
Cyberduck ~ great FTP program
Colloquy ~ IRC client
NVU ~ visual web designing and development software
Gipm ~ graphics editing aka Photoshop
Audacity ~ sound recording software
Camino ~ web browsing
OpenProj ~ open source project management application
jEdit ~ open source text editing software, especially useful for programmers
Stellarium ~ Open source 3D planetarium application
Most of these open source applications, as you can discern, are equally popular to Mac as well as Windows. The biggest advantages of open source computer software are their ease to penetrate the market without the companies offering them requiring to sweat over promoting them and providing a sense of empowerment and flexibility to users and developers. The greatest disadvantages are argued to be their being in a perennially developmental stage and the ignorance of system testing and documentation. This point of concern may be true in case of very small software projects but holds no water for larger, more successful projects which risk no such negligence and their software are well-defined and subject to rules regarding testing of modifications and documentation. Before downloading though, get thoroughly informed about free software download pros and cons to be on the safer side if you are downloading software from some obscure site.

We all have, sometime or the other, used and benefited from some of the best open source software available on the web. Most of you must be familiar with the aforementioned examples and know some of these to be the best things to have happened to web browsing, instant messaging, pod casting, media playing, photo editing and much more – the scopes are unlimited! Download these wicked open source applications and open yourself to more variety and computing convenience. Happy installing!
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