SLR 2/RISC and CISC

Question 1

RISC Meaning

Answer 1

Reduced instruction set computer

Question 2

CISC Meaning

Answer 2

Complex instruction set computer

Question 3

Characteristics of RISC

Answer 3

-Simple instructions, few in number
-Uses more lines of code
-Fixed-length instructions
-Complexity in compiler
-Only LDA/STA instructions access memory
-Few addressing modes
-Requires fewer transistors and less complex hardware
-Uses less power

Question 4

Characteristics of CISC

Answer 4

-Many complex instructions
-Uses less lines of code
-Variable length instructions
-Complexity in microcode
-Many instructions can access memory
-Many addressing modes
-Typically more power required because of more transistors

Question 5

What devices would use RISC?

Answer 5

RISC typically used for smartphones and tablets – usually ARM processors.

Question 6

What devices would use CISC?

Answer 6

CISC typically used for powerful desktop and laptop computers – usually Intel/AMD processors.

Question 7

Doubling the cores on a processor doesnt always mean double the performance, why is this?

Answer 7

Because each core needs to be manage. sharing data between cores will require it to be written to a cache or ram. this is slower than just using registers
Some programs cant make use of multiple cores

Question 8

GPU meaning

Answer 8

Graphical Processing Unit

Question 9

Characteristics of the GPU

Answer 9

-Co-Processor
-Thousands of stream processors but slower than a CPU core
-More specialized for tasks whereas a CPU is general purpose
-Uses SIMD (single instruction multiple data)
-Excels at performing simple operations at large data sets
-Can take advantage of this when graphical processing requires thousands of calculations at a time

Question 10

Multi-Core Processors

Answer 10

-Single Chip containing 2 or more cores.
-Each core can fetch, decode and execute
-Cores placed on a chip multiprocessor (CMP)
-Share cache for all cores

Question 11

Parallel Processing

Answer 11

-The process of program instructions by dividing them between multiple processors.
-Runs program in less time
-For example 1 processing unit could be fetching , another unit could be decoding and another could be executing

Question 12

When could Parallel Processing not work?

Answer 12

-Dependent on the task
-Dependent on whether the software can even make use of parallel processing