# The Computer Revolution/Hardware/Ports
## INFRA-RED Port

History:
The notion of infra-red was developed by Sir William Hersehel in the 1800's. The infra-red port is designed to communicate with other devices equipped with IRDA ports without the use of wires.
Examples of infra-red enabled devices include:
* T.V.
* VCR
* PDA's
* Laptops

## USB Ports
#### Purpose of USB

USB was designed to be low cost and to be used in cheap devices like mice and game controllers with the ability to connect multiple USB devices and have faster speed and also easier to use with its capability of "plug and play", which allows you to remove the device while the PC is running.

#### The USB Connection and Its Standards

The newest version of USB is 2.0 and most of the PCs today have the 2.0 USB port. Older PC versions that have USB 1.1 will have to buy a 2.0 add-on upgrade to be able to hook up 2.0 USB devices. One of the benefits USB ports have is what is called a "daisy chain", or the ability to connect multiple USB devices to a single USB port on one computer. When more USB devices are needed a USB hub can be connected which enables the "daisy chain" to become very large. The problem with chaining too many devices is that the data signal weakens. There are some USB ports like modems, that are more efficient and transfer data faster when connected directly to the main USB port on the PC. Wireless USB technology was introduced in 2004 which can be very useful in home and office environments, because it ranges from 9 to 30 feet. Wireless USB products became available in 2006. Fire Wire is an analog of USB cable, designed and used on all products created by Apple Corp. This is a high-speed external connector that provides connection between a computer and peripheral devices. For the specialist is also known as IEEE 1394. Simply how it works. There are two kinds – backplane bus- rates are 12.5,25, or 50 MB per second and the cable interface – rates are 100, 200 or 400 MB per second. Fire Wire provides two types of f data transfer: asynchronous and isochronous. Asynchronous is for traditional load-and-store applications where data transfer can be initiated and an application interrupted as a given length of data arrives in a buffer. Isochronous data transfer ensures that data flows at a pre-set rate so that an application can handle it in a timed way. For multimedia applications, this kind of data transfer reduces the need for buffering and helps ensure a continuous presentation for the viewer. Comparing a similar Universal Serial Bus (USB) and Fire Wire could find a couple differences. USB is less expensive, but the data transfer is limited to 12 Mbps.

## Dedicated

Dedicated ports are computer interface slots which are connected to a computers motherboard for the sole purpose of its defined application; other hardware needing uses to this port will earth have to be conformed of not use it at all. The most common applications are external: mouse and keyboards. The reverse of a general port.

## SCSI

SCSI ports (pronounced "scuzzy") are for transmitting fast data to up to seven devices in a daisy chain. SCSI stands for "small computer system interface". Personal computers are able to communicate with hardware such as disk drives, tape drives, CD-ROM drives, printers and scanners much quicker. The current set of SCSIs are parallel interfaces that were developed at Apple Computer and are still used in the Macintosh today. SCSI ports continue to be built into PCs today, and as such, are supported by all major operating systems.
SCSI is also more flexible than previous parallel data transfer interfaces. Ultra-2 SCSI can transfer data up to eighty megabytes per second. Seven to fifteen devices can be connected to one SCSI port in the daisy-chain fashion, dependent on the bus width. One circuit board or card can accommodate all the peripherals.
The original SCSI is known as SCSI-1, which evolved into SCSI-2, also known as "plain SCSI" because it became widely accepted. SCSI-3 has extra specialized command sets that meet the needs of specific device types.
A SCSI standard is Ultra-2 which increases the burst rate up to 80 megabytes per second. It has a longer cabling distance of up to twelve meters because it uses low voltage differential signalling. This low voltage differential lowers power requirements and manufacturing costs.
The latest SCSI standard of Ultra-3 increases the burst rate from 80 megabytes per second to 160 megabytes per second. It does this by operating at the full clock rate as opposed to the half-clock rate of Ultra-2. Disk drives supporting Ultra-3 have faster data transfer rates. As well, Ultra-3 ensures the integrity of transferred data.
As we know, computer technology advances rapidly, and it is only a matter of time that a new SCSI standard of Ultra-4 is developed.

## Enhanced

Specialized Expansion Ports
Ethernet is the most widely-installed local area network (LAN) technology. Ethernet was developed by the Xerox Corporation in 1970. An Ethernet LAN typically uses coaxial cable or special grades of twisted pair wires. The coaxial cable was later replaced with point-to-point links connected together by hubs and/or switches in order to reduce installation costs, increase reliability, and enable point-to-point management and troubleshooting. Ethernet is also used in wireless LANs.
The Infra-red Data Association, often referred to as IrDA, is a non-profit organization whose goal is to develop globally adopted specifications for infra-red wireless communication. IrDA was formed in 1994. IRDA is a port much like what you would find on your TV/VCR remote. This port allows two computers or a computer and a device to communicate amongst each other without the use of wires. For the devices to communicate via IrDA they must have a direct line of sight.
Musical Instrument Digital Interface (MIDI) ports are used to connect electronic musical instruments, computers, sound cards, samplers and other show equipment to exchange data. There are many different cables/connectors that are used to transport MIDI data between the devices. MIDI does not transmit audio, it simply transmits real time digital data.
Bluetooth ports consist of short-range radio waves that transmit up to 30 feet. It is used to connect cell phones to computers but also to connect computers to printers, keyboards, headsets, and other appliances. Bluetooth wireless technology simplify communication and synchronization between devices. It is a global standard that eliminates wires and cables between both stationary and mobile devices. It also facilitates both data and voice communication. It offers the possibility of ad hoc networks and delivers the ultimate synchronicity between all your personal devices.
FireWire ports speed up the movement of multimedia data and large files and enable easy connection of digital camcorders, cameras, digital video tapes/disks, PCs, TVs, printers and music systems directly to a personal computer. The connection enables simple, low-cost, high bandwidth realtime data interfacing. FireWire is Apple Computer's name for the IEEE 1394 High Speed Serial Bus. FireWire is similar to a USB port, but much more powerful. Users can transfer images with no image degradation.
The original FireWire was faster than a USB when it first debuted. The initial FireWire had transfer rates of up to 400Mbps. The difference between FireWire and USB are that FireWire are built for devices that work with a lot of data i.e audio equipment. FireWires can connect up to 63 devices. Firewire devices are known as hot pluggables, which mean they can be connected and disconnected at any time. FireWire devices allow devices to draw their power from their connection. The latest version of FireWire cables use a 9 pin configuration but some Firewire devices use 4 pin configurations to save space. Today FireWire cables can achieves speeds up to 800 Mbps. http://computer.howstuffworks.com/firewire4.htm

## Parallel
### Definition

According to authors William and Sawyer the definition of a parallel port is equal to 8 bits (1 byte). Below is a picture of what a parallel port looks like.
Often a parallel port will be used for connected a printer to the computer. A parallel port is beginning to be phased out and USB is taking over what a parallel port once did.

## Serial Ports

A serial port is considered to be one of the most basic external connectors on the computer. It is a connector for a line that sends bits one after another. Serial ports are usually used to connect peripheral devices such as keyboards, monitors, and modems because they do not require fast transmission of data. A serial port is also useful for sending data over a long distance.

## External SATA ports

eSATA ports are used most commonly with external hard drives. The connection through the port is much faster than it a USB or FireWire port. The reason for the faster speed is because eSATA does not have to translate the data between the computer and the interface. When using a USB or FireWire port, the data must be translated before the command can be executed. This characteristic also translates to less lag during the connection process when using an eSATA port. An eSATA port provides a signal for the external devices, but not power; therefore, the device does need its own power supply. The connector cables are much narrower than some used with much older technology. Resources: http://www.wisegeek.org/what-is-esata.htm http://port16.com/blog/2007/11/01/what-is-esata/