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REVISE EDEXCEL

Edexcel curriculum (2015)


Python

Binary/Hex

Data representation

Compression

Encryption

What is a computer?

Working computer

Hardware

Operating system

Computer processes

The CPU

Memory

Input devices

Output devices

Data storage

Inside the CPU

Stored program

F-D-E cycle

CPU components

Networks

LAN, WAN and PAN

Network topologies

Network addressing

Protocols

Error detection

The internet

The world wide web

HTML and CSS

Client-server model

VPNs

SQL

Impact

Ethical issues

Microcontrollers

Comp models

Emerging trends

Virtual machines

Models and sims

Algorithms


The CPU


Inside the CPU are various areas that carry out various functions

CPU registers

Program counter (PC) - an incrementing counter that keeps track of the memory address of the instruction that is to be executed next or in other words, holds the address of the instruction to be executed next.

Memory address register (MAR) - holds the address of a memory location of which data/instruction is to be fetched/written

Memory data register (MDR) - a two-way register that holds data fetched from memory (and ready for the CPU to process) or data waiting to be stored in memory. (This is also known as the memory buffer register (MBR).)

Instruction register (CIR) - a temporary holding ground for the instruction that has just been fetched from memory.

Control unit (CU) - decodes the program instruction in the IR, selecting machine resources such as a data source register and a particular arithmetic operation, and coordinates activation of those resources.

Arithmetic logic unit (ALU) - performs mathematical and logical operations.


System bus

Buses are the connective wiring found in the motherboard.

Data bus
Transfers binary data from place to place

Control bus
Sends and receives signals that control the CPU and other components

Address bus
Carries the binary address of memory locations



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  • Exam boards
    • OCR past papers >
      • Paper1 (Sample)
    • Edexcel past papers >
      • 2020 Current spec (coming soon) >
        • Programming Language Subset (PLS)
      • Old 2016 SPEC >
        • Paper 1 (specimen1)
        • Paper 1 (specimen2)
        • Paper 1 (2018)
        • Paper 1 (2019)
        • Paper 2 (specimen1)
        • Paper 2 (2018)
        • Paper 2 (2019)
      • OLD 2013 SPEC >
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    • Paper 1 (by topic) >
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      • Binary
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      • File size
      • Flow chart
      • Hexadecimal
      • High Level language
      • ISP/Internet
      • Logic
      • Magnetic HDD
      • Networking
      • Open source
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      • Peer to peer
      • Images (Data representation)
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      • RAM
      • ROM
      • Run length encoding
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