Session Objectives#3
COULD explain the role memory plays in computer processing
SHOULD describe the purpose of a CPU and its individual components
MUST identify components of a CPU
Explore key factors affecting computer performance.
A-Level Computing#BristolMet
Processing Components
Starter...
Convert the binary digits
denary)
10 1101
to decimal (also known as
32 16 8 4 2 1
X1 x0 x1 x1 x0 x1
=32 =0 =8 =4 =0 =1
= 32+0+8+4+2+1
= 45
All instructions and data are stored in a computer
as binary numbers. The organisation and structure
of a computers’ processing components is known as
computer architecture.
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Processing Components
The Central Processing Unit (CPU or Processor)
This is the core of every computer system and
it processes instructions from the various
programs that are running.
They consist of 2 main components:
i)the Control Unit (CU) which uses electrical signals to direct
the system to excecute the instructions in stored programs. It
controls the order and flow data to be executed
ii)The Arithmetic and Logic Unit (ALU) which carries out all the
mathematical and logical operations i.e addition, subtraction
and comparisons (relational operations such as =, < and >)
In order for a processor to function it also needs to access 2
things; Main Memory or RAM (Random Access Memory) where the
programs are stored whilst in operation, and cache memory which
is used to store data whilst waiting to be processed.
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Processing Components
Main Memory (RAM) & Cache Memory are called Primary Storage (or
Primary Memory).
Knowledge Gap - What is secondary storage...?
Cache memory is very fast memory and is located close to the
CPU. It also a lot more expensive compared to RAM. Modern
computers have Level 1 (L1), L2 and L3 Cache memory with the
numbers referring to the distance from the CPU in that order. L1
is built into the chip itself. L3 is further away on the
motherboard (Printed Circuit Board PCB) .
The closer the cache the faster the CPU can access the data and
execute instructions.
NB Cache Memory and RAM are both known as volatile memory since
they can be erased, which allows them to take on board new data.
They also need power to store data.
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Processing Components
Data BUSES –
the processing components are connected on the
motherboard via circuits called buses which allow the transfer
of data and control signals. The speed of the buses also affect
how fast a computer can perform operations.
TASK: Attempt to draw a block diagram
illustrating the architecture of the given
example.
A-Level Computing#BristolMet
Block diagram of computer architecture
Main Memory (RAM)
Other devices,
Hard disk drives,
USB ports, DVD
drives
Front Side Bus (FSB)
CPU
(CU, ALU & LI
Cache)
Back Side Bus (BSB)
Southbridge
L2 Cache
L3 Cache
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Northbridge
RECAP
Learning check – what do we now know???
Name the 2 components of a CPU?
What are they used for?
What is primary storage and what does it consist of?
How data is transferred around a motherboard?
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Processing Componets
A dual-core processor simply has 2 CPU’s working together. They
may both have their own cache memory or may share L2 or L3 cache
but since they can fetch, decode and execute instructions at the
same time so the computer is able to process more instructions
as a whole. What affect will this have on performance?
CPU Core & L1 Cache
CPU Core & L1 Cache
Back Side Bus
Interface to bus and
L2 Cache
TASK: Using sticky notes label as many internal parts of the
computer as you can.
A-Level Computing#BristolMet
Processing Components
Consolidate learning:
Questions:
1. What is the purpose of the CPU in a computer?
2. What is a dual-core processor?
3. What are the names given for CPUs with 4 cores, 6 cores and 8
cores?
4. Describe how cache memory and RAM are used by the CPU?
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