Components Of A Personal Computer Flashcards
Computer hardware
Computer organisation
Main physical components of a computer system:
Input/output
CPU
Memory unit
Others: Motherboard Power supply Storage devices Ports and cards
Hardware
Describes the physical components of a computer system which can be categorised as input devices, a CPU, internal and external memory and output devices
Mother board/ system board
A circuit board inside the mirror computers plastic case. It contains integral components including:
CPU chip
Memory chips (RAM and ROm chips)
I/O interface: the channel between the CPU and other devices (keyboard, monitor, etc)
Expansion slots: connectors on the motherboard where expansion cards like display card can be connected
Other logic circuits
Cooling systems
Perform better when kept cool
They are kept cool using active and passive cooling solutions
Active solutions require power while passive don’t
Passive solutions for cooling usually involve reducing the speed at which a component is operating or adding heat sinks to computer chips
E.g. a case fan is an active cooling
CMOS (Complementary metal-oxide-semiconductor )
Attached to the mother board
Its the same as a watch battery or a battery for a remote to your cars alarm system
Keeps the memory for fare and time for BIOS setting
Power supply
A computer uses Direct Current (DC)
Power supply is a device that converts AC (Alternating Current) to DC to run the computer
Power supplies vary in size and Power (in watt)
UPS (Uninterrupted Power Supply) keeps the computer running for a few minutes even when the electricity supply goes off
A desktp PCs powee supply has a fan in it and when you start up the PC, the fan starts up too. The fan pulls hot air out of the power supply and has a side benefit of circulating air through the entire system unit too.
Cards
An expansion device that provides an existing computer with certain added capabilities
Eg
Video/display card: generates the text and graphic images for the monitor while sound card generates sound.
Sound card
I/O card: provide a place for connecting your mouse and printer
Controller card: connects cables of hard disks and floppy disks.
Memory card
Network Interface Card (NIC): a computer circuit board or card that is installed in a computer so that it can be connected to a network.
Ports
Components used as pathways for flow of data. The rear of a PC has many empty holes or external sockets.
Eg
Serial port: used to connect a mouse, modem or scanner
Parallel port: used to connect a printer
Game port: used to connect a joystick while a video port is a connector for the monitor
USB (Universal Serial Bus): can be used to connect many types of input, output and storage devices.
Video Graphics Adapter: the older, analog type used for display
The audio component for plugging in speakers, headphones and microphones. Pink for microphone, green for speakers or headphones and blue for line input.
Central Processing Unit (CPU)
Performance all the processing of input data
It accepts instructions and data and executes them, storing the result in memory
Determines how fast your computer will run and is measured by its Gigahertz (GHz) (Billion instructions per second) or Megahertz (MHz) (Million cycles per second) speed.
Components:
Arithmetic/Logic unit
Control unit
Registers
Arithmetic/Logic Unit
Responsible for all arithmetic operations like additional as well as logic operations such as less than. Logic operations: Evaluates conditions Males comparisons Can compare
Control Unit
Responsible for controlling the transfer of data and instructions among other units of a computer. It manages and controls all units of a computer.
Functions:
Directs and coordinates all operation called for by the program
Activates the appropriate circuits necessary for inputs and output devices
Causes the entire computer system to operate on an automatic manner
Machine cycle: Fetch the instruction Decode the instructions Execute the instructions Store the results
Registers
Holding areas for both data and instructions
Types
For holding data (Data registers)
Hold instructions (instructions registers)
Store logical ststes
Temporary values that serve as increment counters
Small memories inside the CPU They are: Special purpose High speed Temporary storage Located inside CPU
System unit
Houses the primary devices that perform operations and produce results for complex calculations.
Memory unit
Used to store data, instructions and information before, during and after processing by the ALU
Volatile/ dynamic memory: stores data only until the computer is turned off.
Non volatile/ static memory: retains whatever you put in it indefinitely.
Read Only Memory (ROM)
Stores the BIOS (Basic Input Output System) that runs when the computer is powered on
Data and instructions can be read but not modified and instructions are typically recorded at factory.
Its permanent and not erased when the computer is switched off. (Non volatile)
Random Access Memory (RAM)
Used to store data and instructions during the execution of programs
Its temporary and is erased when the computer is switched off. (volatile)
Its a read/write type of memory
How computer memory is measured
Byte = 8 bits Kilobyte = 1024 bytes Megabyte = 1024 kilobytes Gigabyte = 1024 megabytes Terabyte = 1024 gigabytes
Storage unit
Primary memory stores data, instructions and information temporarily during processing by CPU. When the computer is switched off, this memory gets erased.
Used to store data, information and software permanently so that they can be retrieved whenever required
Types of storage
Secondary
Data that will eventually be used
Long term
Eg hard disk, CD, DVD
Primary Data that will be used in the near future Temporary Faster access than storage Eg RAM, ROM
Registers
Data immediately related to the operation being executed
Father access than memory
Hard Disk Drives
An electro mechanical data storage devices that uses magnetic storage to store and retrieve digital data using one or more rigid rapidly rotating platters
Used to store operating systems, application programs
Much faster than CD ROMs and floppy disks and can also hold more data
Can be internal and external but most are internal installed ins8the system unit
Floppy diskette
Small portable magnetic disks
Hold limited amount of data
Tape drives
Used for archiving data
Use a magnetic read or write head and removable tale cartridge
Vary between GBs and TBs
Semi conductor storage solid state drives SSD
Store data as electrical charges in semi conductor flash memory
Much faster than magnetic HDDs
Capacity ranges from around 120GBs to many TBs
Have no moving parts, make no noise, more energy efficient and produce less heat than HDDs
They are more reliable than HDDs.
Optical storage devices
Optical drive uses a light beam and sensor to read the data
Compact disc holds up to 900MB of data. Used for small amounts of data and also for audio recordings.
DVD are used to distribute large applications, large amounts of data and standard definition moves
Blu Ray discs are used to distribute even larger amounts of data or high definition movies
All 3 are ROM
Network drives
It is located on another computer or a server where space is provided for storage of data from many computer terminals
Flash memory and memory cards
Flash memory: rewritable and non volatile. Used in portable devices such as digital cameras, cell phones and hand held computers.
Memory cards are used to store monetary value or can serve in place of disk storage in a small computer.
Cloud storage
A cloud is a secure computing environment consisting of a set of remote severs that users access via the Internet
Can include applications, communication with other users and storage space
Peripheral devices
Any device that you can attach to your computer
