Higher Computing - Computer Systems

Flashcards for Computer Systems Higher

Fetch-Execute Cycle

Fetch-Execute Cycle

The process in a computer where instructions are fetched from memory and executed by the CPU.

Fetch-Execute Cycle Stages

• Transfer the contents of the Program Counter to Memory Address Register (MAR)

• Increment the program counter

• Activate Read Line (transfers instruction to data register)

• Transfer contents of data register to instruction register to decode

• Decode the instruction

• Execute the instruction

Firewall

A program that monitors and filters network traffic to protect a computer from harmful files and unauthorized access.

Encryption

A method of protecting data by scrambling it using public and private keys.

Public Key

A key that is visible to everyone and used to encrypt data.

Private Key

A key that is only visible to the owner and used to decrypt encrypted data.

Digital Signature

A signature created using a private key to verify the authenticity of a message.

Cache

A small, fast storage area that stores frequently accessed data for quicker access.

L1 Cache

Level 1 Cache, stored directly on the processor chip, with limited storage capacity and quicker to access than other backing storage methods.

L2 Cache

Level 2 Cache, larger than L1 Cache and stored off the chip, with more storage capacity, but slower to access than L2 cache

Cache Hit

When the processor successfully finds the requested data in the cache.

Cache Miss

When the processor cannot find the requested data in the cache and has to access it from slower memory.

Threads

Individual parts on the core that allow for multiple instructions to be carried out at once

Improving Performance

• Widen Data Bus

• Overclocking

• Increasing Cache Size

• Having more cores

• DO NOT MENTION WIDENING ADDRESS BUS

DOS Attacks

Denial of Service attacks aim to disrupt or deny access to a system or website by sending thousands of requests or packets to a website or server in order to starve it of resources.

Floating Point Representation

A method of representing real numbers in computer systems using sign, mantissa, and exponent.

File Size Suffixes

• Bits (b) - 0 or 1

• Bytes (B) - 8 bits

• Kilobytes (KB) - 1024B

• Megabytes (KB) - 1024KB

• Gigabytes (GB) - 1024MB

• Terabytes (TB) - 1024GB

Copyrights, Designs and Patents Act

A law that protects intellectual property rights and imposes penalties for infringement.

Computer Misuse Act

Legislation that makes hacking and spreading viruses illegal, with penalties including imprisonment and fines.

Communications Act

A law that regulates digital communications and makes cyber terrorism and unauthorized sharing of explicit content illegal.

GDPR (General Data Protection Regulation)

Regulations that protect individuals' data and impose obligations on companies regarding data usage and privacy.

RIPA (Regulation of Investigatory Powers Act)

A legal act that requires businesses to inform individuals when their data is being recorded and provides access to law enforcement agencies when necessary.