INTERNAL SYSTEM UNIT COMPONENTS
This section discusses internal
system unit components and gives basic explanation to help you put your
answer together to explain the function of computer hardware components.
Processor
is the brains of any computer system. Also known as a CPU or central
processing unit it is used to execute instructions that enable the
operating system and application software to run on a system. A
processor performs arithmetic and logical calculations in the ALU
(arithmetic logical unit) and control instructions in the control unit.
The processor communicates with storage devices such as the hard drive
RAM to process information used to control the operating system and
applications that run on a computer system. Processors are being made
smaller and faster all the time and this allows systems to carry out
instructions faster and perform better. A processor in a mission
critical system used in space or a medical device needs to be very
powerful to carry out instructions quickly processors are integrated
into a computer system by placing them on the motherboard. The processor
requirement for window7 operating system is 700 MHz processor (about
Intel caldron or better). A motherboard is like the body of a computer
system it contains a socket to house the processor and links a lot of
internal components together such as RAM and graphics cards using
communication buses. They have integrated controllers to enable the
processor to communicate with storage devices such as HDDs and CD/DVD
drives. A motherboard is a printed circuit board (PCB) and links the
components using lines drawn on the circuit board. Motherboards contain
expansion slots to insert RAM or graphics, sound and network cards to
improve system performance. They allow a computer engineer to upgrade
the RAM so that a machine runs faster. Motherboards also contain sockets
to enable a computer system to communicate with external devices using
USB ports, sound jacks and VDU outputs, a motherboard comes in different
form factors (this is the shape and size) and you need to check if
components are compatible with this form factor before purchasing them. A
phone also has a motherboard which is much smaller than that used in a
PC obviously, PC motherboards normally require them to be cooled to keep
components running at optimal performance. This is done using fans and
heat sinks.
BIOS or basic input/output system is firmware (firmware links hardware and software) built into a computer system. The BIOS is used to ensure that a system boot up correctly and all hardware components are configured to work correctly. It contains information about the hardware components connected to the system such as keyboard and mouse and enables application installed on the system to be controlled by the hardware. The BIOS is stored in non-volatile ROM (read only memory) of a system and is configured to allow that motherboard and all connected components and peripherals to run correctly.
A power supply or PSU (power supply unit) is used to power all of the components in a computer system. The power supply runs from 120 or
240 volts mains supplied and provides 12v, 5v and sometimes 3.3v outputs to power different components. A hard drive needs a power supply to run and the PSU has a specific output connector that can be used to connect to different hard drive types. Standard connectors are ATX – you can find out more by researching the different type of connector that power supplies have.
A fan is used in a computer system to suck hot air out of the system to make sure that it does not overheat. Most computer systems will have fans on the casing to suck the hot air out of the system. The fans are connected to the power supply. Most processors also have a fan connected to them to draw the heat away from them and ensure they operate at the best speed possible. You will hear a system that is getting hot become noisy as the fans increase in speed. Heat nks are also used to keep systems cool. Heat sinks are made from materials that draw heat away such as aluminum and copper. Often a heat sink is placed on top of a processor to draw the heat away from it. A fan will be placed on top of the heat sink to continuously draw out the heat that the processor produces. This heat is then drawn away from the systems by fans placed on the casing. Sometimes water is used to cool systems that are prone to heating up you can investigate this further to see how water cooling is used in gaming systems as an example. For a computer system to run it needs a storage system to store information about the operating system and applications. Knowledge of hard drive configuration and controllers is an important skill to have when setting up a system. There are different ways to communication with HDDs (hard disk drive) such as SATA, IDE or EIDE. SATA or Serial ATA (Serial Advanced Technology Attachment) is a serial communications method that communicates over a serial cable. If your motherboard is configured with SATA then you need to buy a SATA compliant HDD. IDE (Integrated Drive Electronics) that has the controller for the hard drive stored on the drive itself. Master/slave hard drive configuration means that both drives can be controlled using a single cable. The IDE controllers in each HDD talk to each other to say when it is ok for the system to send or receive data to and from the storage device. If the master drive is in use it will send a message to the slave to tell it that, when the master drive is finished communicating with the system it will send a message to say that the communications are complete and the slave can go ahead and perform the required actions. This is normally configured using hardware jumpers to say with is the master and which the slave drive is.
Most computer systems use ports such as USB, parallel and serial to communicate with external devices. A USB (universal serial bus) port allows you to plugin in an external storage device such as a keyboard or mouse to connect to the motherboard and enable the user to control the system. The motherboard comes with a USB controller chip to enable the communication to take place. Parallel ports were initially used for printers and are not as common these days. They are used for devices that need a lot of communication such as a plotter used in sign writing. They have more communication lines than a serial port and therefore can send and receive more data.
