top computer hacker

James gained notoriety when he became the first juvenile to be sent to prison for hacking. He was sentenced at 16 years old. In an anonymous PBS interview, he professes, "I was just looking around, playing around. What was fun for me was a challenge to see what I could pull off."
James's major intrusions targeted high-profile organizations. He installed a backdoor into a Defense Threat Reduction Agency server. The DTRA is an agency of the Department of Defense charged with reducing the threat to the U.S. and its allies from nuclear, biological, chemical, conventional and special weapons. The backdoor he created enabled him to view sensitive emails and capture employee usernames and passwords.
James also cracked into NASA computers, stealing software worth approximately $1.7 million. According to the Department of Justice, "The software supported the International Space Station's physical environment, including control of the temperature and humidity within the living space." NASA was forced to shut down its computer systems, ultimately racking up a $41,000 cost. James explained that he downloaded the code to supplement his studies on C programming, but contended, "The code itself was crappy . . . certainly not worth $1.7 million like they claimed."
Given the extent of his intrusions, if James, also known as "c0mrade," had been an adult he likely would have served at least 10 years. Instead, he was banned from recreational computer use and was slated to serve a six-month sentence under house arrest with probation. However, he served six months in prison for violation of parole. Today, James asserts that he's learned his lesson and might start a computer security company.

scanning images

A scanner's capability to capture dynamic range is governed by the bit depth used an output as well as system performence. the higher the pixels per inch(ppi), the longer it takes to scan the slide. to ensure a high quality scan, you ought to predetermine the scanning resolution and dynamic range required by the image. the scanning resolution should not be greater than the resolution of the display unit, which is usually 640*480 pexels.
when scanning images to be incorporated into a multimedia application, you should usually scan at a resolution between 300 and 600 dpi.
for exporting the scanned image into a multimedia application, you must change its resolution to 72 dpi.
different types of scanners have different resolution. for example: a flatbed scanner can scan at 300 to 400 dpi. high-end hand scanner offer 600 to 1200 dpi resolutions.
lowering the resolution while scanning adn increasing it later will delete some original colour resolution information and resulting image will not be as sharp as the original.

Instant Messaging (IM)

IM is an acronym for Instant Messaging. It is ‘a tool that successfully supports informal communication’. A form of IM is SMS technology. In an example of IM in practice, IM in its SMS form has proved to be extremely effective amongst a group of hearing impaired students. With the assistance of IM technology, these students were able to communicate in real time and use this medium as a tool to facilitate communication with their teachers without the support of an interpreter.

The most common use of IM within an e-learning context has been to produce a cooperative learning environment. Users if IM are said to be able to articulate ideas, issues and opinions in real time. As such, IM can be used to engage and maintain learner interest as correspondence occurs in a timely manner. Although some people may become confused by chat dialogue or the functionality of chat room discussion, it would appear that the positive facets of IM far outweigh limitation.

Challenges facing organizations are to find other way to engage and become part of the emerging technologies. SMS is a synchronous learning object which in an e-learning context can provide the student with real time and instant learning opportunities.  SMS or IM, as a real-time communication tool can also be utilize as delivery option for hearing-impaired students. This allows them to access teachers without a third party to interpret. Learners can also use this to get automated feedback from assignments or questions, freeing the tutor from any additional workload.

JavaScript’s Role in the World Wide Web and Beyond

Many of the technologies that make the World Wide Web possible
have far exceeded their original goals. Envisioned at the outset as
a medium for publishing static text and image content across a
network, the Web is forever being probed, pushed, and pulled by content
authors. By taking for granted so much of the ‘‘dirty work’’ of conveying the
bits between server and client computers, content developers and programmers
dream of exploiting that connection to generate new user experiences and
practical applications. It’s not uncommon for a developer community to
take ownership of a technology and mold it to do new and exciting things.
But with so many web technologies — especially browser programming
with JavaScript — within reach of everyday folks, we have witnessed an
unprecedented explosion in turning the World Wide Web from a bland
publishing medium into a highly interactive, operating system–agnostic
authoring platform.
The JavaScript language, working in tandem with related browser features, is a
web-enhancing technology. When employed on the client computer, the language
can help turn a static page of content into an engaging, interactive, and
intelligent experience. Applications can be as subtle as welcoming a site’s visitor
with the greeting ‘‘Good morning!’’ when it is morning in the client computer’s
time zone — even though it is dinnertime where the server is located. Or, applications
can be much more obvious, such as delivering the content of a slide show
in a one-page download while JavaScript controls the sequence of hiding, showing,
and ‘‘flying slide’’ transitions as we navigate through the presentation.
Of course, JavaScript is not the only technology that can give life to drab web
content. Therefore, it is important to understand where JavaScript fits within the
array of standards, tools, and other technologies at your disposal. The alternative
technologies described in this chapter are HTML, Cascading Style Sheets (CSS),
server programs, and plug-ins. In most cases, JavaScript can work side by side
with these other technologies, even though the hype can make them sound like
one-stop shopping places for all your interactive needs. (That’s rarely the case.)
Finally, you learn about the origins of JavaScript and what role it plays in today’s
advanced web browsers.

Abstract Classes

Abstract classes involve the use of a common base class when you want to leave certain details
up to its inheritors—specifically, when you need to create a foundational object whose methods
are not fully defined. You will find that by using abstraction, you can create very extensible
architecture within your development projects.
For example, file-format parsing lends itself particularly well to the abstract approach. In
this case, you know that the object will need a set of methods, like getData() or getCreatedDate(),
in order for it to interoperate with other classes; however, you want to leave the parsing methods
up to inheriting classes that are designed for a specific file format. By using abstract classes,
you can define that a parse() method must exist, without needing to specify how it should
work. You can place this abstract requirement and the fully defined methods in a single class
for easier implementation.
You might think of abstract classes as partial classes because they do not define the implementation
for all the methods they declare. Instead of implementing all methods, an abstract
class has the added ability to define abstract methods, which are method prototypes lacking a
body. These methods will be implemented when the class is derived. However, an abstract class
doesn’t need to consist solely of abstract methods; you’re free to declare fully defined methods
as well.

Anti Virus Programs

A computer virus is a program designed to copy itself. The first computer virus was discovered in 1986. Today there are more than 54,000 known viruses and at least 200 are considered threats at any time. Combination threats are becoming more and more common also. A combination threat combines Internet worms, viruses, and Trojans.

Worms differ from viruses because worms do not infect other files as viruses do. Instead of infecting other files a worm makes copies of itself over and over again. Worms can reduce system resources such as hard disk space or reduce bandwidth by spreading over network shares. Today’s worms are also called internet worms or email worms. These worms send copies of themselves to recipients in infected users’ address books. These types of worms can cause loss of productivity and revenue, as email servers can not handle all of the traffic. A Trojan is program that seems to be valid but in fact it does something to harm your computerEarly viruses were pieces of code attached to common program such a game or word processor. A user might download an infected game from a bulletin board and run it. A virus like this is a small piece of code in a larger program.