Tuesday, August 16, 2011

Hardware in a Comptuer

The main box of your computer is reffered to as a System Unit.
  • The inside of the system unit on a desktop consists of most of the following components; 
A Motherboard, RAM, Video Card, CPU, FAN and Ethernet Cards.
Processors - The processor, also called the central processing unit (CPU), interpretes and carries out the instructions given by the software. Contains a Control Unit and an Arithmetic Logic Unit (ALU).

Processor -> Memory -> Output Devices (Information), Input Devices (Data) -> Storage Devices.

The control unit is a component of the processor that directs and coordinates most of the operations in the computer.

For every instruction, a processor repeats a set of four basic operations which comprise a machine cycle (Fetch, Decode, Execute, Store).

Determine how you plan to use a new computer before selecting a processor. i.e. An Internet Browser who checks emails daily wouldn't need an i7 that is used by Video Production serivces.

Memory - Consits of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data.

Stores three basic categories of information: The OS, Drivers and Settings.

Each location in memory has an address. Memory size is measured in kilobytes (KB or K), Megabytes (MB), gigabytes (GB) or terrabytes (TB).

KB = 1024 Bytes, MB = 1,048,576, GB = 1, 073, 741, 824, TB = 1,099, 511, 627, 776.

Two types of memory Volatile Memory (Loses its contents when power is turned off) and Nonvolatile Memory (Does not lose contents when power is removed).

There are three different types of RAM chips that exist:

Dynamic RAM (DRAM), Static RAM (SRAM) & Magnetoresistive (MRAM).

RAM chips usually reside on a memory module and are inserted into memory slots.

Read-Only Memory (ROM) refers to memory chips storing permanent data and instructions.

Flash Memory - can be erased electronically and rewritten.

Access time is the amount of time it takes the processor to read from the memory. This is measured in nanoseconds. 

Expansion Slots and Adapter Cards

- An expansion slot is a socket on a motherboard that can hold an adapter card.
- An adapter card enhanced the functions of your computer (i.e. Extra Ethernet cards, Videocards, Sound Cards)


Plug and Play is a feature where the computer can automatically configure the adapter cards and other peripherals as you install them.

Ports and Connectors

Firewire ports, HDMI ports, audio in port, network port, composite video in.

A USB Port can connect up to 127 different peripherals together with a single connector. You can attach multiple peripherals using a single USB port with a USB hub.

Buses - A Bus allows the various devices both inside and attached to the system unit to communicate with each other; Data Bus, Address bus. Word size is the number of bits the processor can interpret at any one time.

What are input Devices? An input device is any hardware that allows a computer to receive data. These include; keyboards, mice, joysticks, guitars, remotes, pen inputs, voice input etc.

Digital Cameras:

Two factors affect the quality of digital camera photos:

Resolution, Number of bits stored in each pixel.

Voice input:
Voice input is the process of entering inpt by speaking into a microphone.
Voice recognition is the computer's capability of distinguishing spoken words.

Video input - is the process of capturing full-motion images and storing them on a computer's torage medium.

Scanners and Reading Devices - The image resolution and DPI plays a part in how good the scanned document / image is. Optical character recognition (OCR involves reading characters from ordinary documents. A turnaround document is a document you return to the company that creates and sends it.

Magnetic Stripe Card Readers - Read the magnetic stripe on the back of cards such as: Credit Cards, Entertainment Cards, Bank Cards.

Biometric Inputs such as Iris Recognition System and Fingerprint Reader.

Physically Challenged Users; Devices - keyboards with larger keys, head-mounted pointer, on-screen keyboard.

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