Notesale: Turn your study into money

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Explain the function of computer hardware components
CPU:
The CPU (Central processing unit) is a hardware component of a computer system
which performs all instructions for software running on the system
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The clock speed determines
how fast the CPU can carry out instructions
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The CPU carries out
the instructions using a cycle known as the fetch-decode-execute cycle
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The cycle has three main stages as denoted by its name, the first of which is Fetch
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The address is then
sent from the PC to the MAR which acts as a buffer for the addresses which are waiting
to either read or be written from
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In this stage the address is passed from
the MAR into a bus named an address bus which transfers the address to memory
where its corresponding instruction can be returned
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The MDR also acts as a buffer for data which is waiting to be
written to memory as the result of an execution
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During this stage the PC is also incremented to reference the next
instruction which needs to be decoded by the CPU so that the cycle can restart after
execution
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The opcode that is currently held in the CIR (which
is contained in the control unit), reads the opcode and determines what type of

operation it is
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In most cases
the opcode will be sent to the Arithmetic logic unit; which is used to perform arithmetic
and logic operations, the results of the execution will be sent to memory
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The CPU is connected to main memory through a controller hub on the motherboard
chipset known as Northbridge this is connected to the CPU via a bus called the FSB
(Front side bus): this bus also connects the CPU to the Clock generator which is located
on the motherboard which on certain CPUs means the clock speed can be changed for
the purpose of overclocking (speeding a processors clock speed up) or underclocking
(slowing a processors clock speed down)
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When
the address is transferred from the MAR into the address bus, the address bus attempts
to locate the address in Cache, if it is found then it is known as a Cache hit, otherwise it
is known as a Cache miss and the data from the address is sent from Main memory to
the Cache via the FSB
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Cache is also volatile
similarly to RAM (Random access memory) this means all data stored will be lost if
there is no current passing through the component
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Bit
architecture determines how much data can be processed in a single operation; more
bits means arithmetic operations can be calculated using numbers with more digits, this
increases accuracy and reliability of the CPU when compared with a CPU with a lower
bitrate
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CPUs with higher bit architectures
mean that more total memory can be used in the system; comparing the two most use
bit architectures 32 bit and 64 bit: 32 bit processors can make use of a maximum of
4GB of RAM whereas 64 bit processors can handle 16*10^9GB
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This means that CPUs are
specific to motherboards which support their socket type
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In order to stop this damage from occurring a cooling system is needed, the
most common of which is a fan and heatsink
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The transfers this heat more efficiently as the heatsink has lots of
surface area due to being made from fins
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The heatsink on the right is made from multiple fins and has 6
sides which results in more total surface area meaning heat can be dissipated a faster
rate
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The fan is the second component commonly used in a CPU cooling system
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Below is a diagram of the CPU
cooling process
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Many motherboards have what are known as integrated components these are
components which are actually built into the main PCB of the board and cannot be
removed
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In addition to this the motherboard has other components which work in unison with the
processor so as the clock generator and the chipset
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The chipset

controls the flow of data between the CPU and the other components which are
connected to the motherboard
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Northbridge the faster of the two controllers is connected to the CPU via a FSB (Front
side bus): to which the clock generator also connects to
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Southbridge sometimes called the input/output controller is not connected directly to the
CPU instead it connects to Northbridge where all data travelling to the CPU must go
through instead
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In addition to managing the flow of data the Motherboard also supplies power to many
of the components which connect to it
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BIOS & CMOS:
The BIOS (Basic input output system) is a program which is stored on the motherboard
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The POST loads when the system is started and ensures all hardware components are
working as they are intended to be this stops the system from malfunctioning reducing
risk of damage to stored data or other issues such as overheating if the system cooling
hasn’t working as intended
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The bootstrap loader is a small program contained within the BIOS which will locate the
operating system and initialise it so that it can take control of the system
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The CMOS (Complementary metal-oxide semiconductor) is a memory component
which is integrated into the motherboard
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Similarly to RAM (Random
access memory) the CMOS is volatile and thus will lose all information when a current is
not supplied in order to stop this the CMOS has a small battery that gives it a constant
current
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Power Supply Unit:
The PSU (power supply unit) is a computer component which has two main functions:
firstly, to convert the alternating current mains electricity supply which into a direct
current electricity supply which can be used to power the computer system
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3 Volts direct current
supply which can be used accordingly depending on the power requirements of the
components in the system
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Both of these standards have similar
connections
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The 20 Pin Molex ATX Power Connector
is the main supply to the motherboard in ATX systems
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The 6 Pin
Auxiliary Connector is used to provide 5 Volts and 2x 3
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The 15 Pin SATA Power Connector is used to provide power to any
components which use the SATA standard
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Modular wiring systems mean that the connectors can be removed from the PSU if they
are not in use
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Non modular PSUs do not allow wires to be removed however they are usually cheaper
than their modular counterparts
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Secondary storage mostly comes in
three different varieties: Magnetic storage, optical storage and Flash storage
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) Magnetic Disks are known as HDDs (Hard Disk Drives) and come in a few
different standards: PATA (Parallel Advanced Technology Attachment), SCSI (Small
Computer System Interface) and SATA (Serial Advanced Technology Attachment)
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PATA connects to the Motherboard using a IDE cable a type of cable
which has many wired connections which atc in parallel to transfer data
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Later a standard called EIDE was introduced which supports 1
Master drive and 3 slaves
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SCSI is the successor of PATA and had many improvements over the previous
standard such as faster transfer rates and support for larger capacity drives
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SATA is the current standard this standard differs from the previous ones as it is serial
rather than parallel
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The HDD itself consists of one or more magnetic disk known as platters which rotates
and can be read from or written two by a magnetic head
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Regions are a part of a larger structure known as a sector which contains
enough regions to store 512 Bytes of data
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In order to read from the HDD the magnetic head must move to the correct sector of the
HDD and determine the polarization of the region which it wants to read this is known as
seeking
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In order to write to a HDD the magnetic head must once again move to the correct
sector and polarise the regions which it needs to write to with the correct magnetism
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SSDs have no moving parts and instead use integrated circuits to store information, this

means that SSDs have superior ream and write speeds when compared to HDDs
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All SSDs use the newest SATA standard (SATA3) as the older standards are all too
slow in terms of transfer rate
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Optical disks come in several varieties such as CDs, DVDs and Blu Ray disks
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The disk can later be read using a laser to determine the value of the
grooves
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USB flash memory uses the USB standard for data
transfer
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Ports are used by input and output
devices are connected to the system, all devices have their own specific port and if the
system does not have the port then the device cannot be used
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All ports can be separated into two types serial or parallel; serial means that data is
transferred one bit at a time along a connection, parallel means that multiple bits are
transferred simultaneously down multiple connections this increases the transfer of
data
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The most common port type for input and output devices is USB (universal serial bus)
which is a serial connection for data transfer which can also transfer power to

components
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0 being the oldest standard with a transfer
speed of 12 Mbit/s; 2
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0 which has increased transfer
speed of 480 Mbit/s, the newest standard is 3
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Internal memory:
Internal memory is a type of memory which comes in two types: RAM (Random Access
Memory) and ROM (Read Only Memory)
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RAM is useful
as it is much faster than the forms of storage medium used in secondary storage and
therefore can reduce the bottleneck that occurs when sending data to the processor
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ROM is a non-volatile form of memory which cannot be written to by the system
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Graphic Cards:
the GPU (Graphics processing unit) is a specialised hardware component which is
used to create graphical images to be outputted to an output device connected to the
computer system
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Generally dedicated GPUs are faster as
they have all their own components and therefore don't have to rely on the other
components in the system to do its processing
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GPU speeds vary greatly depending on the price of the GPU: an example of a low
specification GPU is the Nvidia GeForce GT 9600 which has a clock speed of 650 MHz
and 512MB of graphics memory (VRAM) this GPU costs around £100 in comparison an
example of a high specification GPU is the Nvidia GTX 980 which has a clock speed of
1,126 MHz and 4GB of graphics memory however this card is much more expensive
costing around £500
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Output peripherals are devices which convert digital data into real world analogue
information which a user can understand
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Monitors take digitised
images produced by the GPU and display them on a screen
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TFT monitors have several advantages such as the thickness of the monitor
can be made much thinner and have higher resolutions
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Printers take images and mark it onto a physical medium such as paper
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Inkjet printers work by firing small drops of ink onto a medium, usually paper
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Laser printers use a laser to cause static on the printing medium this
attracts an ink called the toner onto the paper which will cause the image to form
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Digital cameras use an array of light sensors which capture light and determine its
intensity and colour using the wavelength store it as a pixel which is then converted into
an image or video
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Peripherals have several different cable types such as Coaxial Cable, Optical Cable and
Twisted pair Cable
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Generally Coaxial cabling has transfer rates of up to
10Mbps
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Optical
cables have fast transfer rates and have been recorded reaching speeds of 1 petabyte

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