Computer Science AS OCR
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1-1-structure-and-function-of-the-processor as5 主题
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1-2-types-of-processor as3 主题
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1-3-input-output-and-storage as2 主题
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2-1-systems-software as8 主题
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2-3-software-development as5 主题
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2-4-types-of-programming-language as4 主题
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3-1-compression-encryption-and-hashing as3 主题
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3-2-databases as3 主题
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3-3-networks as8 主题
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3-4-web-technologies as13 主题
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html as
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css as
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css-styling as
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javascript as
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variables-and-constants-in-javascript as
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outputs-in-javascript as
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selection-in-javascript- as
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for-loops-in-javascript- as
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while-loops-in-javascript- as
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strings-in-javascript- as
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operators-in-javascript- as
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nested-statements-in-javascript as
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functions-and-procedures-in-javascript as
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html as
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4-1-data-types as8 主题
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4-2-data-structures as4 主题
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4-3-boolean-algebra as1 主题
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5-1-computing-related-legislation as4 主题
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5-2-moral-and-ethical-issues as9 主题
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6-1-thinking-abstractly as3 主题
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6-2-thinking-ahead as1 主题
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6-3-thinking-procedurally as3 主题
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6-4-thinking-logically as2 主题
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6-5-thinking-concurrently as2 主题
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7-1-programming-techniques as9 主题
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8-1-standard-algorithms-and-big-o-notation as8 主题
cisc-vs-risc as
Exam code:H046
RISC and CISC
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A computer processor will have an instruction set that it can use to execute programs
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This will vary from one processor to the next
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There are 2 types of processors:
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Complex Instruction Set Computer
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Reduced Instruction Set Computer
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RISC (Reduced Instruction Set Computer)
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Reduced Instruction Set Computer (RISC) consists of a smaller instruction set with more simple instructions
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Each instruction takes one clock cycle to execute which makes it more suitable for pipelining
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Compilers are more complicated so will generate more instructions
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Has fewer addressing modes
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Is usually used in smartphones and tablets
CISC (Complex Instruction Set Computer)
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Complex Instruction Set Computer (CISC) consists of a larger instruction set which includes more complex instructions
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As the instructions are more complex, they can take more than one clock cycle to execute
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Has more general purpose registers
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Instructions take up less space in memory
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Is usually used in laptops and desktop computers
What’s the difference between RISC & CISC?
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RISC |
CISC |
|---|---|---|
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Features |
Has fewer transistors |
Has more transistors |
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Takes one clock cycle per instruction |
Takes multiple clock cycles per instruction |
|
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Suited to pipelining |
Not suited to pipelining |
|
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Compilers are more complicated |
Compilers are less complicated |
|
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Has fewer general purpose registers |
Has more general purpose registers |
|
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Used in smartphones and tablets |
Used in laptops and desktops |
|
|
Has fewer addressing modes |
Has more addressing modes |
|
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Benefits / Drawbacks |
Requires less power |
Requires more power |
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Costs less to manufacture |
Costs more to manufacture |
|
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Takes up more space in memory |
Takes up less space in memory |
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A program that has been written for a RISC processor won’t work on a CISC processor and vice versa
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A program that has been written for a RISC processor won’t necessarily work on another RISC processor as they may have different instruction sets
Responses