# Computer Hardware/Introduction
## Outline

This is a basic outline of what this will become

## Computer Parts and Connectors

This should give people a basic understanding of what the basic and most used computer parts are. These are parts and connections the people use or see. These should all be external.

### Keyboard

A keyboard is a basic Input device. Each time a key is pressed it sends a signal to the computer which tells the computer which key was pressed. The most commonly used keyboard on most PCs (personal computers) is the 108-key keyboard. Also known as the QWERTY keyboard after the first six letters on standard keyboards.

### Mouse

When a mouse is moved it will send signals to the computer that give x and y axis information to the computer so that it can move the cursor on the screen. Typical types of computer mouse are rollerball, trackball, optical, and wireless.
The rollerball mouse uses a rolling ball inserted into the base of the mouse that moves rollers in the mouse that translates to the direction the mouse is sent. A trackball has much the same function as the rollerball, but the trackball remains stationary and it is manipulated by a hand. An optical mouse uses a laser to perform the same function as a rollerball mouse but sends its signals optically. A wireless mouse performs as an optical mouse does but sends its signal infrared to a receiver that is connected to the host computer.

### Monitor

This is a display device that a computer uses to display data. Common connection types are VGA and DVI. VGA is the older analog standard which almost every monitor still supports. DVI can be found only LCD (flat panel) type of monitors, and is a digital transmission as opposed to VGA's analog. DVI is recommended over VGA as the picture will tend to be better quality.

### Connectors

Different items connect to the computer in different ways.

#### Serial

A older legacy type of connection which was used with mice connectors. Serial connections are still used today for transfering data to very simple devices. The serial port has 9 pins on it.

#### Parallel

Mostly used by printers, however new printers have USB connections. This port has 25 pins and looks like a stretched out serial port.

#### PS/2

Used for mice and keyboards. Some computers do not have these anymore as USB is replacing both of them, though PS/2 keyboards are still very popular. If they do, then a keyboard connection will be purple, an mouse connection will be green. It looks something like the S-Video port on the back of your television.

#### USB

Universal Serial Bus: mostly used for connecting wide range of peripherals such as a mouse, printer, keyboard, pendrive, external hard disk etc.. The current standard is USB 2.0, and improvement in speed over the previous USB standard. These are about an inch long and a quarter of an inch high. You can connect up to 128 devices through one hub, or USB port in your computer.

#### Firewire

IEEE 1394 - Can be used to connect up to 63 devices. Usually found attached to media devices such as digital and video cameras. Firewire cables use shielded cable similar to STP with either four or six conductors. Connections are made with either a four or six pin connector

## CPU

This is the "brains" of the computer. It does all of the calculations required to run the software. GENERALLY SPEAKING, the faster MHz or GHz, the faster your computer will run. The architecture and the number of cores also affect how fast your computer will run

### Cache
#### L1

The L1 cache is the closest, smallest and fastest memory a CPU has. It is used to temporarily hold instructions that the CPU will run over and over. It is more efficient to hold temporary data in a L1, L2, or L3 cache than in RAM or a hard disk due to their faster access.

#### L2

The L2 or Level 2 cache is the second closest to the CPU core. It is bigger than the L1 cache, but runs a little slower, and is much smaller than the RAM.

#### L3

This type of cache is becoming more prevalent as microprocessor manufacturers ship more processors with L1 and L2 cache built into the processor. L3 cache is then the extra cache that sits on the motherboard between the processor and main memory, since the processor already contains L1 and L2 cache. Some processors are starting to ship with L3 cache built-in as well to speed up memory operations further. In those cases the L3 cache often sits on a separate area of the die, not built directly into the chip core.

### Buses

This allows the CPU to communicate with the different parts of the system such as the Hard Drive, Graphics Card, RAM, etc...

#### System Bus Speed

This is how fast the connection between the CPU and the Motherboard is. The Motherboard is what every thing plugs in to.

#### Frontside Bus

FSB is also known as the Processor Bus, Memory Bus, or System Bus and connects the CPU with the main memory and is used to connect to other components within the computer. The FSB can range from speeds of 66 MHz, 133 MHz, 100 MHz, 266 MHz, 400 MHz, and up.