Operating Systems & Programming Languages

Introduction

This topic looks at how the different levels programming languages control the computer and how programs are managed/run by operating systems. In this way it connects the previous two topics by linking the high level algorithm design and programming (Unit 4) with the underlying hardware and CPU (Unit 3).

Subpages

Resources

CS GCSE Guru
Low Level Languages
- Play with CPU Simulation - LMC & friends
  - Peter Higginson's LMC, 101 Computing LMC and Mini Challenges
- Compiler Explorer: See the assembly and bytecode produced from different languages: https://godbolt.org/
High Level Languages
- Complete the quiz to find which programming languages is best for you: http://www.bestprogramminglanguagefor.me/
- Explore the "top" programming languages
Operating Systems
- The UNIX OS – 50 years and counting
- How To Program Your Very Own Operating Systems

Crash Course CS Videos

Dot points

High & low level languages

show understanding of the need for both high-level and low-level languages
show understanding of the need for compilers when translating programs written in a high-level language
show understanding of the use of interpreters with high-level language programs
show understanding of the need for assemblers when translating programs written in assembly language

Operating Systems

describe the purpose of an Operating System
- understand the purpose & function of an OS and why it is needed not how it works
show understanding of the need for interrupts ~~and buffers~~ (buffers removed in 2020 curriculum)

Unix and C at Bell Labs

The operating system Unix and the programming language C are now 50 years old and are some of the most influential computer programs ever created.

They were created at Bell Labs in the early 70s by Ken Thompson and Dennis Ritchie, two of the most influential programmers in history.

Ken Thompson (sitting) and Dennis Ritchie working together at a PDP-11

Bell Labs was the research arm of AT&T, a highly funded and influential lab that was a condition of AT&T's monopoly. After the AT&T break-up Bell Labs was slowly shut down. It is now Nokia Bell Labs.

From Wikipedia:

Kenneth Lane Thompson (born February 4, 1943) is an American pioneer of computer science. Thompson worked at Bell Labs for most of his career where he designed and implemented the original Unix operating system. He also invented the B programming language, the direct predecessor to the C programming language, and was one of the creators and early developers of the Plan 9 operating system. Since 2006, Thompson has worked at Google, where he co-invented the Go programming language.

Other notable contributions included his work on regular expressions and early computer text editors QED and ed, the definition of the UTF-8 encoding, his work on computer chess that included creation of endgame tablebases and the chess machine Belle.

Dennis MacAlistair Ritchie (September 9, 1941 – October 12, 2011) was an American computer scientist. He created the C programming language and, with long-time colleague Ken Thompson, the Unix operating system and B programming language. Ritchie and Thompson were awarded the Turing Award from the ACM in 1983, the Hamming Medal from the IEEE in 1990 and the National Medal of Technology from President Bill Clinton in 1999. Ritchie was the head of Lucent Technologies System Software Research Department when he retired in 2007. He was the "R" in K&R C, and commonly known by his username dmr.