LEARNING OBJECTIVES
Identify the purpose of the CPU
SUCCESS CRITERIA
Success Criteria:
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Define the purpose of the CPU
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List the factors that affect the processing of data
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Identify features/components of the CPU.
1.1 Systems Architecture
Learners should have studied the following:
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the purpose of the CPU
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Von Neumann architecture:
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MAR (Memory Address Register)
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MDR (Memory Data Register)
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Program Counter
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Accumulator
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common CPU components and their funtion
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ALU (Arithmetic Logic Unit)
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CU (Control Unit)
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Cache
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the function of the CPU as fetch and execute instructions stored in memory
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how common characteristics of CPUs affect their performance
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clock speed
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cache size
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number of cores
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embedded systems:
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purpose of embedded systems
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examples of embedded sytems.
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EXAM TIP
Main Memory (RAM) & Cache Memory are called Primary Storage (or Primary Memory).
EXAM TIP
The closer the cache the faster the CPU can access the data and execute instructions.
did you know?
The following video shows you how the CPU is made, the video is called from sand to chip. Have a look to get a better understanding of the CPU.
HOME LEARNING
Complete Task 2 for home learning, make sure you describe the importance of Clock speed, Cache and Cores.
You must submit this in your next lesson.
SYSTEMS ARCHITECTURE - LESSON 1
STARTER
Figure out the keywords from the following dingbats:
KEYWORDS
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Central Processing Unit
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Control Unit (CU)
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Arithmetic Logic Unit (ALU)
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Cache
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Registers
INPUT
During year 9, you would have heard how important the CPU is, really, without it the computer is pretty useless. The CPU acts as the brain of the computer system.
The purpose of the CPU is to process data. It is where all the searching, sorting, calculating and decision making takes place in the computer.
So no matter what you do on your computer, whether it be writing an essay, looking at your photographs or checking your emails, the CPU has dealt with all of the data and processing required to make these tasks possible. (Reference Teach-ICT.com)
The CPU is the component which does most of the data processing in a computer. It processes all of the data and instructions that make the system work, it executes programs using the fetch - decode - execute cycle. Tasks which are carried out by the CPU when processing data are:
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Fetches instructions (from memory)
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Fetches data (from memory)
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Decodes instructions
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Executes instructions
The clock speed, number of cores and cache size determine the processing power of the CPU.
The clock speed represents the number of fetch execute cycles / instructions the CPU can process in a given time, therfore the higher the clock speed the faster the CPU will run.
The number of cores determines how many instructions can be carried out at any one time. The more cores the CPU has the more instrictions it carries.
The cache size is storage data inside the CPU. The more CPU cache you have allows the CPU to have faster access to a lot more data it needs to process.
We will look at this in more detail at a later stage.
The CPU consists of 2 main components:
i)the Control Unit (CU) which uses electrical signals to direct the system to execute 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 >)
Think of the CU as a traffic controller and the ALU as a professor
In order for a processor to function it also needs to access Main Memory or RAM (Random Access Memory) where the program data is stored whilst in operation (which have been fetched from the hard disk)
Cache memory is used to store data whilst waiting to be processed, which enables the CPU to fetch the data it needs much quicker then going back to the main memory. You can consider this as a special type of RAM.
ROM (Read Only Memory) – It useful to introduce this at this stage. This data can not be overwritten and the CPU will look to a store of this for the first program to load and exexute when turned on, known as the boot sequence. This data is NOT lost when the power is turned off.
We'll go through this in a lot more detail in the next few lessons.
taSK 1
Lets see how much you’ve actually understood. Answer the following exam questions using Socrative learning. You must complete the answers by yourself. Once completed, submit your response and move onto task 2.
taSK 2
Create a poster for Year 9s explaining the following:
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Clock speed
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Cache
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Cores