what is the function of the clock speed
determines number of fetch-execute-decode cycles per second
- every action in CPU happens within a tick of the clock / clock cycle
what is clock speed measure in
Hertz (Hz)
how many cycles would a 3.8 GHz processor have
3.7 billions times per second
what is Cache size
temporary storage of copies of data + instructions being ** read to + written from** the main memory
what are the advantages of the speed of cache memory
- operates must faster than main memory –> data transferred in and out of cache memory quicker
- much quicker to access than RAM –> makes CPU more efficient –> since less time waiting for data to be transferred
why are copies of data and instructions stored in Cache
- want to avoid retrieving data / instructions from the main memory as much as possible –> takes more time
- save time by have cache memory* already in the processor
what is the system cache uses to optimise speed
- there are 2 or 3 levels of cache
- *fastest cache** = smallest capacity = Level 1 cache
- CPU will optimise use of fastest cache before using next level , or RAM , to improve performance speed
describe the difference type of levels within cache
L1:
- fastest , but smallest in size
- hold most frequently use instructions / data
L2:
- bigger capacity, but slower in speed
- holds less frequently used instructions + data
what is a core
a processor (complete copy of CPU)
what is the function of different numbers of cores
- 1 core can process one operation per clock cycle
- dual-core = 2 operations simultaneously
- quad-core = 4 operations simultaneously
does doubling the number of cores simply double the overall speed?
No
- core communicate with each other –> takes time + efficiency
- many programs are not designed for multiple core –> will not work
what are the factors that will affect the speed of the CPU
- cache size
- clock speed
- number of cores
what is an instruction set
a processors list ofall its specific commands, written in machine code that can be processed + executed by a CPU
what is each command associated with
machine code
what is a mnemonic
mnemonics represent assembly language instructions / machine code to make it easier for humans to understand
what is a embedded system
- a smaller computer system with a dedicated function within a larger system, device or machine.
what is the purpose of embedded systems
control the device and to allow a user to interact with it.
do embedded systems need a full operating system and why?
NO
- only perform limited + very specific tasks
- their input is frequently controlled by a button press / switch
give 5 examples of ab embedded system
- domestic appliances - dishwashes, TV
- cars
- security systems
-central heating system - vending machines
advantages of embedded systems compared to general-purpose computers include:
- limited number of functions = they are cheaper to design and build.
- smaller
- require less power –>some devices run from batteries
- low cost per unit –> can be built using cheaper, less powerful processors
.
what are the limitations of embedded systems
- limited processing resources = more difficult to program + interact with
why must embedded systems be reliable
cannot be modified once manufactured –> the program that controls it is held in the Read Only Memory (ROM)
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PAPER 2 - Algorithms, Programming, Logic46
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Data Packaging9
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Data transmission17
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Error Detection15
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Data representation - Number systems (paper 1)35
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MIN and MAX programs5
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Data representation - Text, sound, images and compression (paper 1)32
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Data Transmission32
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Data Transmission - Error Detection, Check Digits, Encryption27
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Hardware - Computer Architecture30
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Hardware - CPU Performance22
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Hardware - Input + Output devices43
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Data Storage37
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Network Hardware7
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Programming language, translators, IDEs11
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The Internet and the World Wide Web12
