Learn web design, computer maintenance, programming, computer architecture, computer networking, electronics, mathematics, art and graphic design.

The Mechanical Universe

Draw with your finger


Learn more at amazon.com

Regular Expressions Subexpressions
In this article you learned how to use subexpressions to rearrange matches in a regular expression and how to replace the value of a subexpression match in the results. More ...

Area of a Quadrilateral Calculator
If you have a regular quadrilateral there are simple formulas to calculate the area. But if you have an irregular quadrilateral you can calculate its area by viewing it as two triangles bucked up against one another. Find the area of each triangle, and then add them together. More ...

Regular Expression Basics : Match a Set of Characters
A Regular Expression (regex) is a sequence of characters that define a pattern that allows you to search, match, locate, replace, manipulate, and manage text. In this article you'll learn how to use regular expressions to match a set of of characters. More ...

What is an Ethernet Crossover Cable?
When connecting two computers together without a switch or router in between you need a special cable, called a crossover cable, that has the transmit wire pair swapped with the receive wire pair. More ...

Understanding Modern PC Specifications
There is a huge variety of different PCs available out there. Its no wonder that consumers are confused about what to buy. This article explains modern PC specifications. More ...

Use PowerShell and WMI to Get CPU Information
Suppose you want to get some information about the CPU in your computer. Can you remember which Control Panel utility will provide that information? If you use a PowerShell script to access WMI you can always get the information you want no mater how they rearrange Control Panel. More ...

Regular Expression: Alternation
In this article you learn how to create an alternation regular expression that will match alternate patterns in a string. More ...

The Difference Between EoP and PoE
Ethernet over Power (EoP) is a technology for sending network data over power lines. Power over Ethernet (PoE) is a technology for sending power over Ethernet network cables. More ...

Introduction to Windows PowerShell
PowerShell is a more powerful replacement for the command shell. this article explains how to run PowerShell and how to create and run PowerShell scripts. More ...

Inkscape Preferences
Inkscape is a highly configurable application. Many of these configuration options can be set through the Preferences dialog box. There is probably a hundred things you can configure through the Preferences dialog box. Here I'll describe a couple of the most important ones. More ...

Online Color Coded Resistor Calculator
To determine the resistance value of a color-coded resistor, select the colors matching each band from the drop-down lists. More ...

Network on a Chip (NoC)
NoC (Network on a Chip) is a method of placing a much larger number of processors on a multi-core chip. Much like a regular network, NoC has multiple point-to-point data links that are interconnected by routing switches. More ...

Introduction to Operating Systems
An operating system is software that acts as an intermediary between a computer user and the computer's applications and hardware. An operating system can be viewed as a resource allocator. Resources might be CPU time, memory space, file storage space, and input/output (I/O) devices. More ...

How SSL (Secure Sockets Layer) Works
SSL is a security protocol standard that encrypts communication between a web browser and a web server. Any organization that uses their website to transmit, receive, store, or display confidential or sensitive information such as passwords, credit card or bank account numbers, social security numbers, and so on, needs to use an SSL Connection. More ...

Regular Expression Basics : How many Matches?
A Regular Expression (regex) is a sequence of characters that define a pattern that allows you to search, match, locate, replace, manipulate, and manage text. In this article you'll learn how to use regular expressions to count the number of matches. More ...

JavaScript to Copy and Paste Text to the Clipboard
In some applications, rather than the user's selection, you may want to copy the contents of a specific html element to the clip board. Or when the user initiates a Paste, you may want to direct the contents of the user's clipboard to a specific html element on the webpage. Here is the code for this. More ...


See it at amazon.com

Custom Search