Lecture by Leslie Lamport on Computer Science and Algorithms

Jul 6, 2024

Lecture by Leslie Lamport on Computer Science and Algorithms

Introduction

  • Leslie Lamport introduces himself as a computer scientist.
  • Reflects that the field of computer science wasn't recognized when he started his career.
  • Initially began working as a programmer and took time to realize his contributions were scientific.

Educational Background

  • Educated as a mathematician.
  • Approached computer science with a mathematician's mindset.
  • Belief: An algorithm needs a proof of correctness; without it, it's a conjecture, not a theorem.

Key Insights in Computer Science

  • Distinction Between Programming and Coding: Programming involves mental effort and design, whereas coding is similar to typing in writing.
    • Writing involves conveying ideas; similarly, programming is about ideas and functionality.
  • Teaching Programming: Suggests focusing on the program's purpose and mathematical foundation rather than just coding.
    • Criticism of current mathematical education, noting people's fear of mathematics, even among senior programmers.

TLA+ (Temporal Logic of Actions)

  • Developed TLA+ as a language to write down program ideas before coding.
  • Helps engineers think mathematically.

Distributed Systems

  • Definition: Systems where one computer’s failure can affect another unknown computer.
  • Serendipitous interest when he received a paper on distributed databases.
  • Realized the algorithm violated the causality concept from special relativity.
  • Proposed state machine concept for solving distributed systems problems.
    • Ensures computers in a distributed system work in sync as a single state machine. This idea is now fundamental in the field.

Industry Experience and Problem Solving

  • Finds interesting problems in the industry, akin to painting from nature (reference to Renoir).
  • Prefers practical problem solving over theoretical contemplation.

Bakery Algorithm

  • Mutual Exclusion Problem: Prevents multiple processes from using the printer simultaneously.
  • Processes choose a number, and the lowest number gets access.
  • Unique aspect: Works even if the number read is inconsistent (e.g., instead of 47 or 100, the system might read 4700 or 9999).
  • Highlights the elegance and robustness of the algorithm beyond initial design intentions.