File Sharing and Copyright Laws

File Sharing

• Dropbox and Google Drive are easy ways to store and share files.
• Peer-to-peer (P2P) networks are another method of sharing files.
• P2P networks use the BitTorrent protocol connecting computers to share data.
• Copyright protects an author's work from being copied without permission.
• The Pirate Bay is a well-known P2P network often used for copyright infringement.
• The Copyright Act 1994 provides a method for copyright holders to address file sharing on P2P networks.
• Infringers can receive up to three notices from their ISP within a nine-month period.
  • Detection notice: First warning for infringement.
  • Warning notice: Second warning for infringement, issued at least 28 days after the detection notice.
  • Enforcement notice: Final warning for infringement, issued at least 28 days after the warning notice.
• Penalties for infringement following an enforcement notice include:
  • The Copyright Tribunal can impose penalties up to $15,000.
  • The District Court can suspend the infringer's internet connection for up to six months.

ASCII

• ASCII stands for American Standard Code for Information Interchange.
• ASCII associates English characters with numbers, allowing text to be stored as strings of binary.
• Each ASCII code is 7 bits long, representing 128 characters.
• Other encoding schemes exist, including UTF-8 and Unicode.
• The letter 'A' starts at 65 in ASCII.
• The letter 'a' starts at 97 in ASCII.

Number Systems

• Computers use the binary number system, with values of 0 or 1.
• Humans use the decimal number system, with values from 0 to 9.

Data Representation in Computers

• Computers control the flow of electrons for data representation.
• Two conditions are easily recognized:
  • Presence of a voltage represents '1'.
  • Absence of a voltage represents '0'.
• Binary numbers can be converted to decimal values.
  • Example: 101111 = (1 x 2^5) + (0 x 2^4) + (1 x 2^3) + (1 x 2^2) + (1 x 2^1) + (1 x 2^0) = 47.

Prefixes

• A byte consists of 8 bits.
• A nibble consists of 4 bits.
• Bytes are commonly used to measure memory capacity.
• Two sets of prefixes are used: decimal and binary.

Decimal Prefixes

• k = kilo = 10^3
• M = mega = 10^6
• G = giga = 10^9
• T = tera = 10^12

Binary Prefixes

• Ki = kibi = 2^10
• Mi = mebi = 2^20
• Gi = gibi = 2^30
• Ti = tebi = 2^40

Prefixes in Computer Science

• Both decimal and binary prefixes are used in computer science.
• Decimal prefixes are easier to calculate, while binary prefixes are more accurate.

History of Computing

• Computers play a critical role in modern life.
• Early pioneers made discoveries and decisions shaping modern computers.
• There are numerous myths and misinformation surrounding the history of computer science.

Need for Computation

• Before the Industrial Revolution, there was limited need for computation.
• Computation became necessary for:
  • Celestial navigation tables
  • Artillery firing tables
  • Engineering, architecture, insurance, science, and manufacturing.

Charles Babbage

• A Victorian mathematician and inventor known for his ideas about calculating engines.
• He envisioned a calculating engine utilizing the method of finite differences to solve polynomial equations.

The Analytical Engine

• Possessed an architecture similar to modern computers.
• Could solve any problem, not just polynomials.
• Could be programmed, supporting branches, conditionals, and loops.
• Was never fully built.

Ada Lovelace

• Lady Ada Lovelace hypothesized in 1842 that Charles Babbage's Analytical Engine could manipulate symbols beyond numbers, potentially composing music or poems.
• The programming language ADA is named after her.
• She believed the engine could not think independently.

The Universal Machine

• Significant advancements in computer technology emerged during World War II.
• There was an increased need for computation for tasks like artillery firing tables, aerospace design, and cryptography.

Alan Turing

• Demonstrated in the 1930s that a simple computer (Turing Machine) could solve any problem describable by symbols.
• Worked on code-breaking during World War II.
• Contributed to the development of the first program-storing computer at Manchester University.
• Turing was convicted and died by suicide in the 1950s, receiving a pardon in 2013.

The Turing Machine

• Consists of:
  • An infinite input/output tape divided into cells containing symbols.
  • A read/write head.
  • An internal state.
  • A set of rules.

Colossus

• The first programmable digital computer in 1943.
• Ten Colossus machines were built for Bletchley Park, England, to crack the Lorenz code used by the German High Command.
• Designed by Tommy Flowers.
• Used 1500 valves (vacuum tubes).
• Remained top secret until the 1970s.
• The ENIAC was later publicized as the "first computer" in 1945.

The Stored Program Computer

• 1945: John von Neumann published a report called "First Draft of a Report on EDVAC" outlining the stored program concept.
• The "von Neumann machine" structure was based on his report:
  • A memory containing instructions and data.
  • A processing unit for performing arithmetic and logical operations.
  • A control unit for interpreting instructions.
  • Input/output (I/O) devices.

Assembly Languages

• Kathleen Booth is credited with creating the first assembly language in 1947.
• Assembly languages are low-level, human-readable programming languages, translated into machine code by an assembler.
• Assembly languages are tied to specific computer architectures, making the code non-portable.

High-Level Programming Languages

• Grace Hopper earned a PhD in mathematics from Yale University.
• Served in the US Navy, programming the Mark I at Harvard.
• Hopper created the first compiler in 1952.
• Developed the first high-level programming language, "Flow-matic".

High-Level and Low-Level Programming Language Comparison

• High-Level Language:
  • High level of abstraction.
  • Easier to understand and maintain code (resembling English).
  • Easier to learn, attracting a wider range of programmers.
  • Requires a compiler or interpreter for execution.
  • Portable.
• Low-Level Language:
  • Low level of abstraction, closer to machine code.
  • Difficult to understand and maintain code.
  • Requires an assembler for execution.
  • Not portable across different architectures.

Artificial Intelligence

• Computational study of structures and processes supporting intelligent behaviour.
• The term was coined in 1956 at the Dartmouth Summer Research Project on Artificial Intelligence.
• Research areas include:
  • Computer vision
  • Natural language processing
  • Robotics
  • Knowledge-based systems
  • Machine learning.

Aims of Artificial Intelligence

• Three interrelated aims:
  • Engineering Aim: To create computational principles and techniques for building "useful" intelligent artefacts.
  • Psychological Aim: To develop computational principles and theories for understanding human or animal cognition.
  • General/Philosophical Aim: To explore computational principles, theories, and systems for a broader understanding of cognition, including human-made artefacts, naturally occurring organisms, and potential undiscovered entities.

What is Intelligence?

• It's challenging to define intelligence due to the complexity of measuring and analyzing cognitive capabilities.
• Studying intelligence through synthetic tasks (e.g., programming exercises) doesn't always align with "general ability."
• These tasks can be affected by factors like study instructions, leading to inconsistencies in measuring students' abilities.

Teaching Patterns

• Teaching patterns leads to fragile knowledge when students are not taught the underlying principles.
• Students taught specific patterns (A, B, C) may struggle with new problems (D).
• Teaching general programming principles allows students to adapt to new problems.

Large Language Models (LLMs)

• Originally designed for tasks like language classification and translation.
• LLMs are adapted for generating text.
• LLMs can generate code:
  • They receive code as input and generate code as output.
  • They are a powerful tool for programmers, but they are always learning and still make mistakes.
  • They may not understand the underlying logic, only that a certain sequence of code is associated with a certain desired result.

Colour Bitmaps

• Use multiple bits per pixel, mapping binary numbers to colours.

Memory Requirements for Images

• The number of bits required per pixel determines the number of colours that can be represented.
• Example:
  • 1 bit: 2 colours
  • 2 bits: 4 colours
  • 4 bits: 16 colours
  • 8 bits: 256 colours
  • 16 bits: 65536 colours
  • 24 bits: 16777216 colours

Exercises

• How many colours can be represented by 3 bits? - 2^3 = 8 colours
• How many bits are required to represent 128 different colours? - 128 = 2^7. Therefore 7 bits are required.
• How much memory would be required to store a black and white image that is 10 pixels high and 5 pixels wide? Show your working.
  • Number of colours = 2^1. Therefore 1 bit is required per pixel.
  • Number of pixels = h * w = 10 * 5 = 50
  • Memory needed = 50 * 1 = 50 bits
• How much memory (in bytes) would be required to store an image that has 256 different colours and is 3 pixels high and 5 pixels wide? Show your working.
  • Number of colours = 256 = 2^8. Therefore 8 bits are required per pixel.
  • Number of pixels = h * w = 3 * 5 = 15
  • Memory needed = 15 * 8 = 120 bits
  • Since 1 byte = 8 bits, the memory needed is 120 / 8 = 15 bytes.