An Ecosystem of Distributions

Many hundreds of GNU/Linux distributions are in active use today. A quick look at Distrowatch�s database (distrowatch.com) demonstrates the staggering number and growth of distributions. One of the first GNU/Linux distributions was called Softlanding Linux System, or SLS. For a number of reasons, a programmer named Patrick Volkerding thought he could improve on SLS. Because SLS was free software, Volkerding had the freedom to make a derivative version of SLS and distribute it. Volkerding did just this when he took SLS�s code and used it as the framework or model upon which to create his own variant called Slackware. Subsequently, Slackware became the first widely successful GNU/Linux distribution and is maintained to this day.With time, the landscape of GNU/Linux distribution has changed....

What Is a Distribution?

It�s clear to most people that Ubuntu is an OS. The full story is a little more complex. Ubuntu is what is called a distribution of GNU/Linux�a distro for short. Understanding exactly what that means requires, once again, a little bit of history. In the early days of GNU and Linux, users needed a great deal of technical knowledge. Only geeks needed to apply. There were no Linux operating systems in the sense that we usually use the term there was no single CD or set of disks that one could use to install. Instead, the software was dozens and even hundreds of individual programs, each built differently by a different individual, and each distributed separately. Installing each of the necessary applications would be incredibly time consuming at best. In many cases, incompatibilities and the...

The Two Faces of Privacy on Facebook

With Facebook starting out as a personal network, it has been a hard transition for people to become used to it as also a professional network. Most use LinkedIn as a professional network, Facebook as a personal network, and Twitter is a hybrid that people are still trying to figure out. But with the growth rate of Facebook, many have started to turn to it as a personal branding tool and professional network. Marketers have begun turning to Facebook with Facebook Pages, Groups, and advertisements as a way to reach out to their prospects, customers, and fans.This transition has created a dilemma for many folks because they are resistant to using Facebook as a professional network, yet their colleagues, competition, and companies are becoming active on the network. Also, as we develop friends...

Pinguy OS: Linux For Dummies

It�s an old trope, one that has almost entirely lost its meaning over time, but there�s another Linux distro that is designed for the average (or slightly below average) computer user.This one, however, is about as close as any have come to creating an idiot-proof Linux distro. Pinguy OS (www.pinguyos.com) is based on Ubuntu and is mighty fun to play with.A Little BackgroundPinguy OS was built by a fellow named Antoni Norman who wanted a Linux OS that he could give to friends and family�without having to constantly provide tech support. He�d been recommending Ubuntu but grew frustrated with how stark it was. Even though it�s relatively easy to add software, codecs, and the like with Ubuntu�s repositories, he found that many novice users were still having trouble finding everything they needed...

Ubuntu Subprojects, Derivatives, and Spin-offs

Finally, no introduction to Ubuntu is complete without an introduction to a growing list of Ubuntu subprojects and derivatives. While Ubuntu was derived from Debian, the project has also developed a number of derivatives of its own.First and foremost among these is Kubuntu�a version of Ubuntu that uses KDE instead of GNOME as the default desktop environment. However, it is important to realize that the relationship between Kubuntu and Ubuntu is different from the relationship between Ubuntu and Debian. From a technical perspective, Kubuntu is fully within the Ubuntu distribution. Organizationally, the Kubuntu team works fully within Ubuntu as well.A similar organization exists with the Edubuntu project, which aims to help develop Ubuntu so that a configuration of the distribution can be easily...

The History of Computing V - Linux

Some thought that the problem with Windows wasn�t that it was nearly universal�there are advantages to everyone, as far as that�s concerned�but that it was proprietary. That is, it was owned or controlled by one company, which means that no one outside of that company knows exactly how the product works. In computer science, the opposite of proprietary is open-source. That is, no one company owns or controls the product, and anyone can look at how the product works and even make suggestions on how to improve it.In 1991, Linus Torvalds, a student in Finland, made an innocent post to an e-mail group. He wrote that he was working on a free version of UNIX, an operating system that had been in use for twenty years. The Torvalds version, which came to be called Linux (Linus UNIX), was released...

The History of Computing IV - Microsoft Windows

Those earning microsoft certifications may be interested to know more about the history of the company. When IBM was readying its PC for launch, they needed an operating system, which is th core program that allows a computer to function. This is the program that starts to run when you turn on a computer, before you touch the keyboard or the mouse. Microsoft purchased an operating system from another company and adapted it for use on the IBM PC, calling its software MS-DOS, for Microsoft Disk Operating System.In 1985, Microsoft�s initial fortunes were made with MS-DOS, but once Microsoft chairman Bill Gates saw the Apple Macintosh, he knew the days of MS-DOS were numbered. Microsoft developed its own GUI, a program that would run on top of MS-DOS, and called it �Windows.�Few people remember...

The History of Computing III - Apple Macintosh

Although a great improvement over punch cards, some computer scientists saw limitations in a computer with only a keyboard for input and text for output. It was fine for researchers and computer experts to interact with the machine through obscure commands and oblique text messages, but if the computer was going into every home, it needed to interact with users in a different way.In the early 1970s, researchers at Xerox developed a series of computers that communicated with the user through pictures, not just words. The culmination of their early efforts was the Xerox Star. It had �windows,� a �mouse,� and many other elements you would recognize today. Eventually this method of computer use�mostly visual, with little text�would be called a graphical user interface (or GUI), and every computer...

The History of Computing II - The IBM PC

For decades after World War II, computers were shared. Though they had grown smaller since the days of ENIAC, they were still very large and expensive. As a consequence, entire universities or companies, or even groups of schools and companies, would share the use of a single, large, and�for the time�powerful computer.The people who used this mainframe, as these computers were called, would often never see it. The computer was generally locked in a secure location, and users would connect to it through phone lines or other wiring. At first, all the user saw was a teletype, which is like a combination of an electric typewriter and a printer. But later, video screens were introduced, which showed green or orange text on a black background.By the late 1970s, computer scientists realized that...

History of Computing I

The AbacusThe first efforts toward mechanical assistance aided in counting, not computation. An abacus is a mechanical device with beads sliding on rods, which is used as a counting device. It dates to at least the Roman Empire, and its ancestor, the counting board, was in use as far back as 500 B.C. The abacus is considered a counting device because all the computation is still done by the person using the device. The abacus did show, however, that a machine could be used to store numbers.Jacquard�s Mechanical LoomA loom is a machine for weaving a pattern into fabric. Early loom designs were operated by hand. For each �line� in the design, certain threads were �pulled� by an experienced weaver (or a poor worker under the direction of a weaver) to get the finished pattern. As you might guess,...

SUBJECT AREAS IN COMPUTER SCIENCE

Within the computer science field, computer scientists can work in many areas. Depending on the profession, some computer scientists may need to know a little about each area, while others may need deep knowledge of one or two areas.Artificial IntelligenceArtificial intelligence can be described as programming computers to perform tasks that require intelligence if humans were performing the tasks. This is not the only definition, though, and of all the areas in computer science, this one has perhaps the most contentious boundaries. Some researchers believe artificial intelligence must mimic the processes of the human brain; others are interested only in solving problems that seem to require intelligence, like understanding a request written in English.Theory of ComputationThe theory of computation...

What is COMPUTING ?

Computers have become a ubiquitous feature of modern life. It would be difficult to get through a day without some activity involving a computer, be it composing e-mail on a computer sitting on a desk, using a computer hidden inside a cell phone, or receiving a bill generated by a computer at the power company. Computer science allows all these activities to happen.But what is computer science? It sounds simple enough�computer science is a branch of science that studies computers. But not everyone who works with computers is a computer scientist. The use and development of computers comprises a number of overlapping disciplines.Before these disciplines are discussed, you need to understand a few terms.A program is a series of steps to accomplish a given task. In general usage, a program might...

iPhone E-mail

Unlike many other smartphones, your iPhone can send, receive, and browse e-mail without getting weighed down with compromise. The iPhone doesn�t settle for cramped, odd presentations. Your e-mail looks the way it should�the way it would if you were reading it on your home computer. That�s because the iPhone provides an HTMLcompatible rich-text client. Mail looks better because the client is better. It�s made to work right.iPhone mail works with most industry-standard e-mail systems. With it, you can send and receive photos; view Excel spreadsheets, PDF files, and Word documents; manage your accounts; and more. CompatibilityiPhone Mail is surprisingly compatible. It works with virtually all major e-mail providers, including Gmail, AOL, Yahoo!, and Comcast. For businesses, iPhone plays relatively...

Three Ways iPhone Messaging Is Better Than What�s Available on Other Phones

When it comes to messaging, the iPhone offers several advantages over the rest of the field. First, there�s the keyboard. The iPhone keyboard is far easier to use than any other cell phone keyboard. It makes it simple to type and edit messages.For years, teenagers have been wearing their fingers to a nub texting each other. Texting on standard cell phones is hard work. Because of this, an entire language of texting shorthand has sprung up from �lol� (laughing out loud) to �pos� (parents are watching over my shoulder) to �kthxbai� (OK, thank you, good bye). The idea is to keep everything short and easy to type. Unfortunately, clarity is sacrificed to ease of typing. The iPhone brings simple typing back and allows you to properly say �thank you,� instead of �ty� or �thx.�Second, the iPhone remembers...

A Variety of Chats with iPhone

Your iPhone is not only a powerful phone but also a messaging heavyweight. It supports text and multimedia messaging out of the box, can do AIM-style instant messaging and Internet chats with third-party apps, and can even be used for voice and video chats. Social networking services have expanded exponentially over the past few years, and the iPhone has been at the forefront of this explosion.Messaging allows you to communicate instantly with colleagues and friends. It brings people closer together without relying on the immediacy of a phone call. Instant messaging is asynchronous; you send a message, and the recipient can respond to it (or not) at their leisure. That�s unlike a phone conversation, which is synchronous, where you and the recipient have an immediate back-and-forth interchange...

Analyzing Facebook Ad Performance

Facebook provides an excellent reporting tool to gauge the performance of your ad campaign. Analyzing performance is important so that you can make adjustments, not only after your campaign but also during the campaign. By monitoring your performance in real time, or near real time, you can make immediate changes that can turn the tides of a lagging campaign that�s only draining your bank account.When you head into the analytics area, you�re immediately greeted with a dashboard where you get an immediate glance at your campaign. From here you can edit your campaign, its status, the daily budget, or duration. You can also see a roll-up report of the major key performance indicators of your campaign including� Status� Bid� Type (CPC or CPM)� Clicks� Impressions� CTR % (Click-through rate)� Avg....

Common Reasons for an Ad on Facebook to be Rejected

Before we creating a Facebook ad, it is useful to consider the common reasons that your ad could be rejected. Make sure that you don�t use any of these tactics and your ad should pass with flying colors. According to Facebook, the following are the 12 most common reasons for an ad to be rejected:1. Capitalization of every word: Capitalizing every word can give you an unfair advantage over the ads that are running. Also, it is not proper grammar.2. Capitalization of entire words: One of the easiest ways to scream �SPAM� to your target audience is with the capitalization of entire words. We�ve all seen these messages before. Admit it; you�re usually, if not always, turned off by messages such as LEARN HOW TO IMPROVE YOUR SALARY. Even if the message is useful to you, the capitalization of every...

Architecture-Neutral Distribution Format

Within the framework of the OSF (Open Software Foundation) created at the end of the 1980s by a group of information processing systems manufacturers, whose initial goal was to develop a UNIX operating system independent of Sun and ATT, there was an attempt to promote a distribution technology independent of processor architecture. However, this technology, called ANDF was not adopted by industry players. It consisted of distributing the applications in a form of intermediate code (compilers produced this intermediate code instead of generating computer code). Installation then required translation of the intermediate code into computer code. One reason for the failure of this approach could be that software vendors using it might have been presented with a support problem, since the approach...

System Abstraction Layer

SAL allows the portability of the operating systems�in binary format� between various platforms based on the same processor architecture. The role of this layer is to hide the specific details of the platform from the operating systems. Among the principal functions of a SAL are:� The assumption of responsibility of initialization, test and the configuration of the hardware resources of the platform� Providing the operating system with data structures describing the configuration� Provision of basic services for resource management, such as choice of which processor will load (�bootstrap�) the system; basic hardware error management and error logging� Hiding differences arising from the use of different processor architectures, or the use of different processors within a single architectural...

Flynn�s Classification of Parallel Architectures

On the level of systems architectures, Michael Flynn proposed a classification of parallel architectures:� SISD (Single Instruction Single Data), in which just one stream of instructions performs a transformation on a single stream of data (this is the simplest model and corresponds to the computer architecture model described by John von Neumann.)� SIMD (Single Instruction Multiple Data), in which the same stream of instructions is applied to disjoint sets of data� MISD (Multiple Instruction Single Data) in which several instruction streams are applied to the same stream of data, (some sources hold that pipelined execution is the closest approximation to this approach, but we feel that this is a somewhat artificial view, since in a pipelined machine there is but one instruction stream)� MIMD...

Insecure Websites in DMZ Still Pose a Risk

Level of TrustNormally, a website is considered to be a part of the untrusted outer perimeter of a company network infrastructure. Hence, system administrators usually put a web server in the DMZ part of a network and assume the information security risk from the website to the network is mitigated. However, several industry security standards have been imposed to protect the public infrastructure such as webs servers and name servers in addition to the services directly subjected to the standard application scope. Some companies are hiring people with computer forensics degrees to find out where threats are coming from. Why is it so important to protect your website even if it is not closely connected to your critical data infrastructure?Social ImpactHumans are the weakest link in the chain...

The Power and Reach of Facebook Connect

Although 400+ million people is a lot, it still isn�t everyone. Therefore, Facebook must continually come up with new ways to find users. Also, as it�s out searching for new users, it also wants to ensure that it entices back its current user base as often as possible. This provides more opportunities for you, as a marketer, because it increases the possibility for you to connect with new prospects, current customers, and fans of your brand.To accomplish all these goals, Facebook created Facebook Connect. Facebook Connect was released in December 2008. After approximately only one year, Facebook Connect had been integrated, in one form or another, on more than 80,000 websites. On those 80,000 websites, approximately 60 million users have engaged with Facebook Connect. That means that, as of...

Creating a Personalized Experience with Facebook Connect

The capability of Facebook Connect to create a personalized experience is something that we�ve only seen the tip of so far. Facebook Connect has the capability to use some of your information such as age, gender, location, or content that you�ve uploaded to Facebook to help create a story that has been created just for you.To fully understand what creating a personalized experience with Facebook Connect actually means, it is easiest to learn about how some have chosen to use this feature.During Shark Week, the Discovery Channel sought to find ways to pull people in to watch the programming that it had for Shark Week. The Discovery Channel realized that one of the ways to pull people in would be to reach out into the communities where they�re already hanging out. Instead of hoping that they...

Using Facebook Connect as a Single Sign On

The concept of single sign on is something that has continued to float around the Internet as users become increasingly frustrated with how many different websites they have to be signed up for to access content. Such concepts as OpenID have attempted to create a single sign on that people would use on all the websites they visit. The problem with OpenID though is that it requires website administrators to add OpenID functionality to their website. During the middle of this debate over single sign on, Facebook implemented Facebook Connect and instantly enabled 400+ million users to have a single sign on. Yes, just like with OpenID, website administrators need to add additional code to their websites; however, unlike OpenID Facebook Connect also gives you access to the many other features that...

Sharing Stories into Your Stream with Facebook Connect

The ability to share stories into your stream is a feature of some more socially forward websites such as Yelp. On Yelp, once you rate a restaurant, you�re able to push that review and restaurant information to your Wall as a status update. Where this differs from the Share functionality is that with the Share feature, you�re sharing an article from a website or blog. With the ability to stream stories, you�re able to automatically push information to your Facebook Wall while you�re interacting on other websites. This is beneficial to the websites that are able to integrate it because the stream story usually carries some of the branding from the website such as a logo thus bringing increased brand awareness.Several websites allow you the option of publishing your activity to Facebook. You�ll...

An Ecosystem of Distributions

Many hundreds of GNU/Linux distributions are in active use today. A quick look at Distrowatch�s database (distrowatch.com) demonstrates the staggering number and growth of distributions. One of the first GNU/Linux distributions was called Softlanding Linux System, or SLS. For a number of reasons, a programmer named Patrick Volkerding thought he could improve on SLS. Because SLS was free software, Volkerding had the freedom to make a derivative version of SLS and distribute it. Volkerding did just this when he took SLS�s code and used it as the framework or model upon which to create his own variant called Slackware. Subsequently, Slackware became the first widely successful GNU/Linux distribution and is maintained to this day.With time, the landscape of GNU/Linux distribution has changed....

Useful Software Development Tools

Here�s a quick survey of some other candidates for every programmer�s toolbox.Testing ToolsFitNesse: http://fitnesse.org/FitNesse is an acceptance testing tool that allows tests to be expressed as tables of input data and expected output data, described in Fit for Developing Software: Framework for Integrated Tests.Watir: http://wtr.rubyforge.org/Watir is an open source library for automating web browsers allowing automated testing of web applications. It started out on Internet Explorer on Windows but is in the process of being ported to other browsers.Selenium: http://selenium.openqa.org/Selenium is a cross-platform suite of tools to automate web application testing.Sahi: http://sahi.co.in/Sahi is an automation and testing tool for web applications that runs as a proxy server.The Grinder:...

Useful Software Development Libraries

Not all tools are stand-alone�many, covered in this section, come in the form of libraries that we need to link with our own code.TestingThe last few years have seen an explosion in the number of test frameworks, many of which are based upon the seminal JUnit. There�s no way that I can begin to cover them all here, so I will restrict myself to referencing the �big two� in the Java community:JUnit: http://www.junit.org/This is the library that started it all.TestNG: http://testng.org/This is a more recent test framework, which builds upon the ideas in JUnit but takes a few different approaches and is starting to gain a considerable following.Debugging Memory AllocatorsDebugging Memory Allocators, on in languages like C and C++ that don�t provide memory management, a debugging memory allocator...