Introduction to Computational Thinking - Lecture on Operating Systems and the Internet

Instructor

Background: British mathematician, logician, and computer scientist.
Contributions:
- Developed the Turing machine model of computation.
- Demonstrated undecidable decision problems with Alonzo Church.
- Worked on breaking the German Enigma machine code during WWII, crucial for the Allies' victory.
- Post-war, designed the Automatic Computing Engine (ACE).
- Developed the Turing Test, a method to measure machine intelligence.
Legacy:
- Turing Award named after him, equivalent to the Nobel Prize in computing.
- Died by suicide possibly due to persecution for being homosexual.
- Speculation about connection to Apple's logo, denied by Apple.

ASCII (American Standard Code for Information Interchange):
- Based on the English alphabet from old American typewriters.
- Consists of 128 characters (94 printable, 33 non-printable control characters).
- Represented by 7 or 8 bits.
Unicode:
- More universal approach, representing graphemes from more than 130,000 characters and 139 writing systems.
- Represented by 8, 16, or 32 bits.
- Used for public interaction scenarios.

Definition: Software that controls computer hardware and enables application programs to run.
Common Operating Systems: Microsoft Windows, Apple OS X (based on Unix), Linux, Google's Android.
Components:
- Kernel: Controls hardware and provides services to application programs.
  - Services include I/O device management, program execution, memory management, and file system management.
- System Programs: Essential applications provided by the OS.

Graphical User Interface (GUI):
- User interacts through graphical displays on screens (phones, laptops, desktops).
- Requires significant computer resources but easy to use.
Command Line Interface (CLI):
- Text-oriented interaction within a terminal.
- Uses shells (e.g., C shell, bash) for operation.
- Operates on a read-execute-print loop.
- Allows creation of shell scripts for complex tasks.
- Uses fewer resources, offering more power and flexibility but harder for novices to use.