Edexcel curriculum (2015)

Algorithms

Ascii

Binary

Client-Server

Cloud

Compression

Computational think

CPU

Cyber security

Database

Fetch-decode-execute cycle

Embedded system

Encryption

Environment

Ethics

File size

Flow chart

Hexadecimal

High Level language

ISP/Internet

Law & Legislation

Logic

Magnetic HDD

Networking

Open source

Operating system

Optical storage

Peer to peer

Pictures (data rep)

Protocols

Run length encoding

RAM

ROM

Simulation software

Solid state HD

Sound

Stored program

Address bus

Answer
​The more lines/wires/bits the address bus has (1) the more memory locations can be uniquely identified (1)

Address bus

Answer
​Specifies a memory address/uniquely identifies a memory location (1)

Fetch-Decode-Execute cycle

Answer
FETCH:
  • contents of PC transferred to MAR
  • address bus used to transfer this address to main memory
  • contents of addressed memory location moved into the MBR
  • transfer of content used the data bus
  • increment PC
  • transfer content of MBR to CIR.
 
DECODE:
  • decode instruction held by the CIR
  • the control unit decodes the instruction
  • instruction split into opcode and operand.
 
EXECUTE:
  • if necessary, data is fetched
  • the opcode identifies the instruction to execute/operation to perform
  • execute instruction by relevant part of processor
  • result stored in accumulator