Glossary

Stands for "Liquid Crystal Display." LCDs are super-thin displays that are used in laptop computer screens and flat panel monitors. Smaller LCDs are used in handheld TVs, PDAs, and portable video game devices. The image on an LCD screen is created by sandwiching an electrically reactive substance between two electrodes. This color of this substance can be changed by increasing or reducing the electrical current. Since LCD screens are based on the principle of blocking light (rather than emitting it), they use up much less power than standard CRT (Cathode-Ray Tube) monitors.

LinkedIn is a business-oriented social networking website. It allows you to create a custom profile and add other LinkedIn users to your list of connections. Unlike Facebook, LinkedIn profiles are designed to be professional, rather than personal. They appear like a resume, with education and work experience being the most prominent. By using LinkedIn, you can keep in touch with past colleagues and meet new potential business partners.

A UNIX - like, open-source operating system developed primarily by Linus Torvalds. Linux is free and runs on many platforms, including both PCs and Macintoshes. Linux is an open-source operating system, meaning that the source code of the operating system is freely available to the public. Programmers may redistribute and modify the code, as long as they don't collect royalties on their work or deny access to their code. Since development is not restricted to a single corporation more programmers can debug and improve the source code faster.

Logic gates perform basic logical functions and are the fundamental building blocks of digital integrated circuits. Most logic gates take an input of two binary values, and output a single value of a 1 or 0. Some circuits may have only a few logic gates, while others, such as microprocessors, may have millions of them. There are seven different types of logic gates, which are outlined below.

In the following examples, each logic gate except the NOT gate has two inputs, A and B, which can either be 1 (True) or 0 (False). The resulting output is a single value of 1 if the result is true, or 0 if the result is false.

1. AND - True if A and B are both True

    

    

2. OR - True if either A or B are True

    

    

3. NOT - Inverts value: True if input is False; False if input is True

    

    

4. XOR - True if either A or B are True, but False if both are True

    

    

5. NAND - AND followed by NOT: False only if A and B are both True

    

    

6. NOR - OR followed by NOT: True only if A and B are both False

    

    

7. XNOR - XOR followed by NOT: True if A and B are both True or both False

By combining thousands or millions of logic gates, it is possible to perform highly complex operations. The maximum number of logic gates on an integrated circuit is determined by the size of the chip divided by the size of the logic gates. Since transistors make up most of the logic gates in computer processors, smaller transistors mean more complex and faster processors.

A sequence of instructions that is repeated until a prescribed condition, such as agreement with a data element or completion of a count, is satisfied