Network Hardware Components

Network Interface Card:-

A network card, network adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses. It allows users to connect to each other either by using cables or wirelessly.

Repeaters:-

A repeater is an electronic device that receives a signal and retransmits it at a higher level or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances without degradation.
Because repeaters work with the actual physical signal, and do not attempt to interpret the data being transmitted, they operate on the Physical layer, the first layer of the OSI model.

Hubs:-

A hub contains multiple ports. When a packet arrives at one port, it is copied to all the ports of the hub. When the packets are copied, the destination address in the frame does not change to a broadcast address. It does this in a rudimentary way, it simply copies the data to all of the Nodes connected to the hub.

Bridges:-

A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges do not promiscuously copy traffic to all ports, as hubs do. but learns which MAC addresses are reachable through specific ports. Once the bridge associates a port and an address, it will send traffic for that address only to that port. Bridges do send broadcasts to all ports except the one on which the broadcast was received.

Routers:-

Routers are the networking device that forward data packets along networks by using headers and forwarding tables to determine the best path to forward the packets. Routers work at the network layer of the TCP/IP model or layer 3 of the OSI model. Routers also provide interconnectivitybetween like and unlike media (RFC 1812) This is accomplished by examining the Header of a data packet, and making a decision on the next hop to which it should be sent (RFC 1812) They use preconfigured static routes, status of their hardware interfaces, and routing protocols to select the best route between any two subnets. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. Some DSL and cable modems, for home use, have been integrated with routers to allow multiple home computers to access the Internet.

Computer Network

A computer network is an interconnection of a group of computers. Networks may be classified by what is called the network layer at which they operate according to basic reference models considered as standards in the industry such as the four-layer Internet Protocol Suite model. While the seven-layer Open Systems Interconnection (OSI) reference model is better known in academia, the majority of networks use the Internet Protocol Suite (IP) as their network model.

Types of networks:

Personal Area Network (PAN):-

A personal area network (PAN) is a computer network used for communication among computer devices close to one person. Some examples of devices that may be used in a PAN are printers, fax machines, telephones, PDAs, or scanners. The reach of a PAN is typically within about 20-30 feet (approximately 4-6 Meters). PANs can be used for communication among the individual devices (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink).

Local Area Network (LAN):-

A network covering a small geographic area, like a home, office, or building. Current LANs are most likely to be based on Ethernet technology. For example, a library will have a wired or wireless LAN for users to interconnect local devices (e.g., printers and servers) connect to the internet. All of the PCs in the library are connected by category 5 (Cat5) cable, running the IEEE 802.3 protocol through a system of interconnection devices and eventually connect to the internet. The cables to the servers are on Cat 5e enhanced cable, which will support IEEE 802.3 at 1 Gbps.

Campus Area Network (CAN):-

A network that connects two or more LANs but that is limited to a specific and contiguous geographical area such as a college campus, industrial complex, or a military base. A CAN, may be considered a type of MAN (metropolitan area network), but is generally limited to an area that is smaller than a typical MAN.

Metropolitan Area Network (MAN):-

A Metropolitan Area Network is a network that connects two or more Local Area Networks or Campus Area Networks together but does not extend beyond the boundaries of the immediate town, city, or metropolitan area. Multiple routers, switches & hubs are connected to create a MAN.

Wide Area Network (WAN):-

A WAN is a data communications network that covers a relatively broad geographic area (i.e. one city to another and one country to another country) and that often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

Global Area Network (GAN):-

Global area networks (GAN) specifications are in development by several groups, and there is no common definition. In general, however, a GAN is a model for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is "handing off" the user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial Wireless local area networks (WLAN) [1]. INMARSAT has defined a satellite-based Broadband Global Area Network (BGAN).

Monitor

A computer display monitor, usually called simply a monitor, is a piece of electrical equipment which displays viewable images generated by a computer without producing a permanent record. The word "monitor" is used in other contexts; in particular in television broadcasting, where a television picture is displayed to a high standard. A computer display device is usually either a cathode ray tube or some form of flat panel such as a TFT LCD

Modem

Modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over any means of transmitting analog signals, from driven diodes to radio.

Wireless parts of a Computer

Wireless Keyboard.

A Wireless Keyboard is a keyboard that utilizes Bluetooth technology to communicate with the CPU instead of connecting via a plug-in cord. They also need batteries, most often 4 AA batteries, in order to operate. The operational range varies depending on the specific device.

Wireless Mouse.

A Wireless Mouse is a computer mouse that communicates with the CPU via Bluetooth technology instead of via a plug-in cord. The operational range varies depending on the model and they usually operate on 2 AA batteries.

Wireless Joystick.

A lever that moves in all directions and controls the movement of a pointer or some other display symbol. A joystick is similar to a mouse, except that with a mouse the cursor stops moving as soon as you stop moving the mouse. With a joystick, the pointer continues moving in the direction the joystick is pointing. To stop the pointer, you must return the joystick to its upright position. Most joysticks include two buttons called triggers.

Wireless Speaker.

There are two common wireless speaker implementations, both having a similar design, but using different signal transport media. A transmitter device is attached to the speaker connections on the audio source, and a receiving device is attached to, or included in the speakers to be placed remotely. Most wireless speakers are sold as a package with the transmitter, receiver, and speakers themselves included for ease of use. Setting up wireless speakers is a pretty simple activity, but there are some caveats to consider:

Google Developing Mobile OS

Google has been throwing around the possibility of a mobile OS for quite some time now, although there's been stirs of an announcement coming after Labor Day.

This all started with Google's acquisition of mobile software company Android, founded by Andy Rubin. Andy has continued to developed a Linux based mobile OS, which they've shown to several mobile phone makers. It sounds as if Google is outsourcing all the hardware work, and mainly concerning themselves with a highly customizable system with Google integration.

Windows Moble OS

The definitive reference guide for Windows Mobile 6.0 has been released. The guide details the differences and advantages of Windows Mobile 6.0 - and what’s up with all those crazy new names. So, if you just have to know everything about the new mobile OS offering from Microsoft, go download the PDF file today! Just be warned, the Windows Mobile 6.0 Product Reference Guide caters to mobile operators, OEM’s, IT professionals, business users, and developers - us “normal” consumers weren’t even considered. That’s okay, we’ll let this one slide, Microsoft.

Computer - Data Storage Devices

BLU-RAY DISK(BD)

A Blu-ray Disc (also called BD) is a high-density optical disc format for the storage of digital information, includinghigh-definition video.

The name Blu-ray Disc is derived from the blue-violet laser used to read and write this type of disc. Because of its shorter wavelength (405 nm), substantially more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A single layer Blu-ray Disc can store 25 gigabytes (GB), over five times the size of a single layer DVD at 4.7 GB.

USB Flash Drive

USB flash drives are NAND-type flash memory data storage devices integrated with a USB (universal serial bus) interface. They are typically small, lightweight, removable and rewritable.USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They are more compact, faster, hold more data, and are more reliable due to their lack of moving parts, and more durable design.

Floppy Disk Drives / Floppy Disks

Floppy disk drives were originally introduced commercially as a read-only device in the early 1970s. These early floppy disk drives were used to hold microcode and diagnostics for large IBM mainframe computer systems. These disk drives were using 8-inch floppy diskettes recorded on only one side. By changing these diskettes inside the floppy drive, technicians could easily update the microcode to the latest revisions or load diagnostics easily. The storage capacity of these early readonly drives was less than 100 kilobytes.

In 1973 a new upgraded 8 inch drive with read/write capability and a capacity of about 250 kilobytes began shipping which IBM used in data entry systems. This drive incorporated many technical improvements and became a model for drives still in use today. As time went on, designers learned how to reliably record on both sides of the diskette as well as increase the density of the data recorded on the diskette.

Modern floppy drives and diskettes (3.5 inch) have evolved to a much smaller size with larger capacities as well. In 1980, the 3.5 inch floppy drive and diskette was introduced by Sony. During the early 1980's many competing formats were tried to compete with the 3.5 inch drives. Over time the industry settled on the 3.5 inch format which was standardized and manufactured by many companies. Today's standard 3.5 inch diskettes hold a formatted capacity of 1.44 megabytes while still using the same basic technology of the second generation 8 inch drives.

Floppy Drive Troubleshooting, Problems & Support(Click Here)

Hard-Disk Drives (Hard Disks)

The hard drive, also called the hard disk or fixed disk, is the primary storage unit of the computer. It is always labeled the C drive. Additional drives are labeled after it as the D, E, F, etc. It has several read/write heads that read and record data magnetically on platters, a stack of rotating disks inside the hard drive.

Types of Hard Drives
(1) Bournolli has a mechanism that acts as a fly wheel. When the HD spins the disk follows gravities course and is lifted up a few centimeters causing the Read/Write heads to touch. When it stops spinning, the HD will fall back down the few centimeters.
(2) Magnetic Optical Drive has the best storage capacity. It has the same principles as the Bournolli, but is mixed with the Compact Disc technology so that the Read/Write head puts data in order and the laser reads off of it.
(3) Standard Magnetic Drive The standard magnetic drive is less complex and less expensive than the others. It stores data with a read/write head which sends a pulse of electricity through causing the magnetic films electrons to line up in a certain way.

Types of Hard Drive Connections
(1) Integrated Device Electronics (IDE)
(2) Small Computer Interface (SCSI)
(3) Enhanced Integrated Drive Electronics (EIDE)

The CD-ROM Technology.

The Compact Disc-CD was invented in 1982 by two well-known companies, Philips and Sony. This was an Audio CD, digital audio. Soon the computer industry recognized that the large amount of digital audio data could be replaced by digital computer data.
CD-ROM (Compact Disc Read-Only Memory) represents a new important tool for the storage, retrieval, and the distribution of information. CD-ROMs can store and play back audio, video, graphic images, digital data, and digitized text.

Types of Compact Disks.
(1) CD-DA : Audio CD, Digital Audio by Philips and Sony
(2) Photo CD : Developed by Kodak and Philips
(3) Video CD : Can hold around 70 minute of video footage
(4) CD Extra : For Multimedia and developed in 1996
(5) CD-R : Well known technology for WORM disks
(6) CD-RW : Rewritable (erasable)-CD, developed in 1995

Digital Video Disc (DVD)

Digital Video Disc or Digital Versatile Disc (DVD), an optical storage device that looks the same as a compact disc but is able to hold about 15 times as much information and transfer it to the computer about 20 times as fast as a CD-ROM. A DVD, also called a Super Density disc (SD), can hold 8.5 gigabytes of data or four hours of movies on a side; double -sided and rewriteable DVD discs are available now.