How Do Computers Communicate

hugepedia — Mon, 06 Dec 2010 09:13:38 +0000

The personal computer may be the greatest invention in the history of mankind. Of course there are other very important technologies, developed to support the personal computer as well. For example, ships are very important, because the communication between continents was first made possible by putting cables on the bottom of the ocean. Without ships this wasn’t possible. A more advanced solution for communication between different parts of the world is done with the help of satellites, but these are extremely high-tech, compared to a couple of wires and fiber optic cables sitting on the bottom of the sea.

The first personal computers weren’t made for global communication. In the beginning operation systems and software were very vulnerable. Large companies had networks within their buildings between their own computers, but even the simplest virus could make the whole system shut down. The first relatively secure operating system came out in 2000, the Windows 2000 Professional. Computers were powerful enough to run antivirus and firewall software in real-time to prevent the spread of harmful software on the network in 2000, so the increased security was achieved by manufacturing better software and hardware.

Today it’s very easy to set up a small local network and connect it to the World Wide Web. All computers are equipped with at least one kind of network card (wired for desktops, wireless & wired for notebooks). The central unit of any local area network is a switch or hub, which redirects data packages (packets) to the computer they were addressed to on the network.

An average switch can connect up to 8 computers. The only limitation is the 100m maximum length of one UTP (8-wire, twisted pair) cable used between switches or between a computer and a switch. In some situations, this distance can be increased up to 200m by lowering the transmission speed and using high-quality components, but usually if two parts of the network are farther away than 100m, then network developers use other technologies such as cable modems (can transmit over a few kilometers), DSL modems and the extremely high-speed fiber optic cable, the favorite one of every network user.

Data transmitted over any kind of computer network comes in the form of packets, which can be perceived as letters. Each packet contains the address of the sender, the actual data and the address of the recipient. No matter how complicated a network structure is, the most popular network protocol (TCP/IP) always finds the shortest route between the two computers that communicate to each other.

Every network device has two different types of addresses. One is the MAC address, responsible for the proper transmission of packets on a hardware level between neighboring devices, and the IP address (Internet Protocol Address) which is closer to software and it can be changed by the user or by the network administrator.

I intentionally haven’t mentioned wireless networks, because they are very unstable when compared to any type of wired network. To make a long story short, Wi-Fi, GSM and 3G networks use radio signals, that are very environment dependent. Some types of buildings simply block any kind of radio waves, so wireless networks aren’t really for anyone. If there are no obstacles in the path of the radio waves, with a standard Wi-Fi antenna data can be transmitted up to a ~100m radius without a significant speed decrease. Using professional directional antennas greater distances can be covered, up to a couple of km, but this solution is also relatively unstable.

3G signal can travel up to 50km between the client device and the main tower, in cities however maximum distance is drastically reduced by the presence of large buildings. If the signal is too weak transmission speed may drop to a couple of kilobytes/second if the device is able to connect at all.

There’s another obvious problem with wireless networks, which is the health risk for all living creatures (plants included). While some radio wave frequencies seem to do good for brain functions short-term, the long-term effect is cancer and/or death. Most people don’t have high tolerance for radio waves, while is some geographical locations children are born immune to most kinds of radiation.

All types of networks connected to the Internet will soon face a huge problem: we have run out of IP addresses. Version 4 of the Internet protocol will soon be replaced by version 6, which will offer 340,282,366,920,938,463,463,374,607,431,768,211,456 IP addresses instead of only 4 billion supported by IP V4.

As impossible as it may seem, I predict that these addresses will run out too, as the number of Internet connected devices grows every day. When they introduced IP V4 they didn’t predict how soon all addresses will be taken as 4 billion seemed to be an unreachable number.

Basic Computer Hardware

hugepedia — Wed, 03 Feb 2010 14:50:54 +0000

Computer hardware is the physical part of the computer including the digital circuits inside the computer as opposed to the software that carry out the computing instructions. The hardware of a computer is unlikely to change frequently unless due to the crash or for upgrading them. The devices that is capable of storing, executing system instructions and controlling other logical outputs.

Hardware comprises all of the physical part of the computer such as Monitor, CPU, motherboard, ram, CD-Rom, printer, scanner, hard disk, flash drive (AKA pen drive), processor, pci buses, floppy disk, power supply, VGA card, sound card, network interface card, peripherals, joystick, mouse, keyboard, foot pedal, computer fan, camera, headset and others.

CPU (Central Processing Unit): CPU or central processing unit relates to a specific or processor. The performance of the computer is determined by the CPU chip (processor speed) and the other computer circuitry.

Hard Disk Drives – Disk drive is the mechanism to run the disks. All disks need a drive to get the information, read it and put it back to the disks. Hard disk is used to store the data permanently. Often the terms disk and drive used to describe the same thing but it should be clear that a disk is a storage device.

Modem – A modem is used for the modulation and demodulation of the data that is transferred through the modem and the telephone lines. Modem translates the data from digital to analog from analog to digital. Because on the telephone lines data can travel in the form of the analog signals and in the computer data transmits in the form of digital signals. Modems are measured by the speed which is called baud rate.

Video cards-Video cards allow computer to display video, graphics and animation. Some video cards allow computers to display television. A video card with a digital video camera allows users to produce live video. A high speed broadband internet connection is required to watch the videos on net.

Network cards: Network interface cards allow PCs to connect with each other and communicate. Every network computer is required to have a NIC card. NIC cards are required both in wired and wireless networking.

RAM (Random Access Memory) RAM is a memory that is being used by the computer to store the information temporarily. For example when some work is performed on some applications that work is temporarily stored in the RAM. More RAM in the computer more faster computer works.

Cards – Cards are the hardware components that are added to the computer to increase their functionalities and capabilities.

Memory – Memory is the one of the important piece of the hardware. Sometimes memory chip memory is confused with the hard disk memory. Sometimes unallocated space of the hard disk is used as virtual memory also known as page file. This type of memory is a temporary memory and is used actual memory is less and requires some additional memory to perform a specific task.

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How Do Computers Communicate

Basic Computer Hardware