Introduction
If you can, imagine a time before computer programs or the invention of the Internet. Websites didn’t exist, books, printed on paper and tightly bound, were your primary source of information. It took a considerable amount of effort to track down the exact piece of information you were after and old fashion elbow grease solved all of the worlds problems. Today you can program a machine to do work or open a web browser and search away. Any bit of imaginable information rests at your fingertips. And chances are someone somewhere has invented a robot to do your work or built a website with the exact information you were looking for.
Before we work with software and begin to learn any programming languages, it is important to know a little bit about computer hardware and to understand how a network and the internet works.
Before we work with software and begin to learn any programming languages, it is important to know a little bit about computer hardware and to understand how a network and the internet works.
Computer Hardware
The central processing unit (CPU), also called a processor, is located inside the computer case on the motherboard. It is sometimes called the brain of the computer, and its job is to carry out commands. Whenever you press a key, click the mouse, or start an application, you're sending instructions to the CPU.
The hard drive on your computer is where the software is installed, and it's also where your documents and other files are stored. The hard drive is long-term storage, which means the data is still saved even if you turn the computer off or unplug it. When you run a program or open a file, the computer copies some of the data from the hard drive onto the RAM. When you save a file, the data is copied back to the hard drive. The faster the hard drive is, the faster your computer can start up and load programs.
The motherboard is the computer's main circuit board. It's a thin plate that holds the CPU, memory, connectors for the hard drive and optical drives, expansion cards to control the video and audio, and connections to your computer's ports (such as USB ports). The motherboard connects directly or indirectly to every part of the computer.
RAM (Random Access Memory) is your system's short-term memory. Whenever your computer performs calculations, it temporarily stores the data in the RAM until it is needed. This short-term memory disappears when the computer is turned off. If you're working on a document, spreadsheet, or other type of file, you'll need to save it to avoid losing it. When you save a file, the data is written to the hard drive, which acts as long-term storage.
The power supply unit in a computer converts the power from the wall outlet to the type of power needed by the computer. It sends power through cables to the motherboard and other components.
Most computers have expansion slots on the motherboard that allow you to add various types of expansion cards. You may never have to add any PCI cards because most motherboards have built-in video, sound, network, and other capabilities. However, if you want to boost the performance of your computer or update the capabilities of an older computer, you can always add one or more cards.
The hard drive on your computer is where the software is installed, and it's also where your documents and other files are stored. The hard drive is long-term storage, which means the data is still saved even if you turn the computer off or unplug it. When you run a program or open a file, the computer copies some of the data from the hard drive onto the RAM. When you save a file, the data is copied back to the hard drive. The faster the hard drive is, the faster your computer can start up and load programs.
The motherboard is the computer's main circuit board. It's a thin plate that holds the CPU, memory, connectors for the hard drive and optical drives, expansion cards to control the video and audio, and connections to your computer's ports (such as USB ports). The motherboard connects directly or indirectly to every part of the computer.
RAM (Random Access Memory) is your system's short-term memory. Whenever your computer performs calculations, it temporarily stores the data in the RAM until it is needed. This short-term memory disappears when the computer is turned off. If you're working on a document, spreadsheet, or other type of file, you'll need to save it to avoid losing it. When you save a file, the data is written to the hard drive, which acts as long-term storage.
The power supply unit in a computer converts the power from the wall outlet to the type of power needed by the computer. It sends power through cables to the motherboard and other components.
Most computers have expansion slots on the motherboard that allow you to add various types of expansion cards. You may never have to add any PCI cards because most motherboards have built-in video, sound, network, and other capabilities. However, if you want to boost the performance of your computer or update the capabilities of an older computer, you can always add one or more cards.
Video Card
The video card is responsible for what you see on the monitor. Most computers have a GPU (graphics processing unit) built into the motherboard instead of having a separate video card. If you like playing graphics-intensive games, you can add a faster video card to one of the expansion slots to get better performance. |
Sound Card
The sound card, also called an audio card, is responsible for what you hear in the speakers or headphones. Most motherboards have integrated sound, but you can upgrade to a dedicated sound card for higher-quality sound. |
Network Card
The network card allows your computer to communicate over a network and access the Internet. It can either connect with anEthernet cable or through a wireless connection (often called Wi-Fi). Many motherboards have built-in network connections, and a network card can also be added to an expansion slot. |
Bluetooth Card
Bluetooth is a technology for wireless communication over short distances. It's often used in computers to communicate with wireless keyboards, mice, and printers. It's often built into the motherboard or included in a wireless network card. For computers that don't have Bluetooth, a USB adapter, called a dongle, can be purchased. |
Networks & The Internet
Unlike technologies such as the light bulb or the telephone, the Internet has no single “inventor.” Instead, it has evolved over time. The Internet got its start in the United States more than 50 years ago as a government weapon in the Cold War. For years, scientists and researchers used it to communicate and share data with one another. Today, we use the Internet for almost everything, and for many people it would be impossible to imagine life without it.
The internet could not work without protocols. A protocol is a set of rules in which computers communicate with each other. Without a common set of protocols between devices, communication would not be able to happen. Each machine must understand the signals that are being sent to it and its signals must be understood by the machines that it is sending signals to. The Internet is many networks loosely connected to one another through a common protocol called Hypertext Transfer Protocol (HTTP). The HTTP is designed to enable communications between clients and servers, and works as a request-response protocol between a client and server. A web browser may be the client, and an application on a computer that hosts a web site may be the server. The web browser takes in a web address or Uniform Resource Locator (URL) and assumes that you are requesting a web page by assessing the HTTP. Then, your request is sent out into the Domain Name System (DNS) or the way that Internet domain names are located and translated into internet protocol addresses or IP Address. An IP Address is a numerical label assigned to each device participating in a computer network and a domain name is a meaningful and easy-to-remember "handle" for an Internet address. If the DNS can convert the URL to an HTTP page, then the response (sent to your computer, the client), will include the header and the body of the web page. The Machines that store the information that we are accessing online are called servers and the connecting points along the path from which the information travels is called a Node. The information on the Internet is stored on the hard drives of web servers all over the world. The World Wide Web never "runs out of space" because additional servers can always be added.
Quick Videos
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The History of the Internet as presented by the History Channel
Basic Concepts presented by Code.org
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http://mentalfloss.com/article/60150/10-facts-about-internets-undersea-cables
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The Internet of Things
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Access for all
The Internet is possibly the greatest invention of the 20th century and will likely spawn the greatest ideas of the 21st century. Yet, more than half of the world's population is still without access. Check out the projects below which are working in creative ways to to help everyone get online.