1.1 The characteristics of contemporary processors, input, output and storage factors

Question 1

What are Von Neumann, Harvard, and contemporary processor architechtures?
(1.1.1)

Answer 1

Von Neumann: shared memory & data bus for both data & instructions

Harvard: physically separate memories for instructions & data, common in embedded, useful for different memory characteristics / optimisation

Contemporary: mixed, Von Neumann for data & instructions in RAM, Harvard for cache

Question 2

What are RISC and CISC processors and how do they differ? (1.1.2)

Answer 2

RISC: small instruction set, 1 instruction per cycle

CISC: Large set, minimising assembly lines, more in embedded

Comparsion:

• More compiler work in RISC, translating high-level 🡆 assembly
• RISC more RAM needed
• Pipelining in RISC (as 1 cycle)
• CISC few instructions actually used

Question 3

What factors affect processor performance and why? (1.1.1)

Answer 3

• Clock speed (synchronises / limits CPU operations)
• Number of cores (simultaneous processing)
• Cache (fast memory inside CPU, quicker than RAM, frequent instructions)

Question 4

What is the function of the Arithmetic Logic Unit? (1.1.1)

Answer 4

Completes mathematical calculations & logical operations.

Question 5

What is the function of the Control Unit? (1.1.1)

Answer 5

• Controls / coordinates CPU activities
• Manages data flow
• Decodes instructions

Question 6

How is pipelining used to improve efficiency in a processor and what types of it exist? (1.1.1)

Answer 6

Allowing 3 separate instructions simulatenous fetch, decode, execute cycles, holding data in buffer. Reduces idle components in CPU.

Instruction pipelining: separating instructions

Arithmetic: breaking down operations

Question 7

What are the function of all of the CPU’s registers? (1.1.1)

Answer 7

• PC: Holds next instruction’s address
• ACC: Stores calculation results
• MAR: Holds address of reading / writing location
• MDR: Temporarily stores read, or upcoming written, data
• CIR: Holds current instruction being executed, divided into operand / opcode

Question 8

What is ROM? (1.1.3)

Answer 8

• Read-only
• Non-volatile
• Unmodifiable
• Stores fixed instruction sequences (e.g. computer startup routine)

Question 9

What is the differences between multi-core and parallel systems? (1.1.2)

Answer 9

• Multicore: multiple independent cores, separately, faster for larger
• Parallel: single core with threading

Question 10

What are the benefits and drawbacks of each of the 3 types of storage devices?
(1.1.3)

Answer 10

Magnetic:

• Benefits: high storage capacity, low cost per GB, suitable long-term
• Drawbacks: slower read/write, physical damage susceptibility, moving parts

Optical:

• Benefits: immune to environment, portable, suitable for distribution
• Drawbacks: lower capacity, slower read/write, easy to damage

Flash:

• Benefits: fast read/write, no moving, more durable, silent, portable
• Drawbacks: high cost per GB, finite RW cycle limit

Question 11

What is virtual storage and what are its qualities? (1.1.3)

Answer 11

• Remote information storage (e.g. cloud/networked)
• Internet speeds 🡅, virtual storage 🡅
• Multiple drives acting as one
• High costs, internet-reliant

Question 12

What are the functions of the buses? (1.1.1)

Answer 12

• Control: Bi-directional, transmit commands, timing, status, interrupts,
  between components
• Address: Transmits memory addresses for retrieving / sending
• Data: Bi-directional transporting data / instructions between components

Question 13

What occurs in the FDE cycle? (1.1.1)

Question 14

What is a GPU and what is it used for? (1.1.2)

Answer 14

Co-processor, instructions for common graphic operations & multiple data pieces
at once, highly multicore

Used for: image-processing, machine learning, data mining.

Question 15

What is RAM? (1.1.3)

Answer 15

• Random-access
• Fast, volatile
• Stores currently used data / programs
• Speeds computer execution
• More expensive than secondary