Hardware + Software

• Hardware


  Physical parts of computer - Internal and External
• Software


  All of the programs in a computer
• Internal Hardware


  Motherboard, Hard Drive, RAM ...
• External Hardware


  Monitor, Keyboard, Mouse, Printer, Webcam ...
• Software


  System, Application and Utility
• System Software


  Important things that make the computer run
• Application Software


  Apps running
• System Software Examples


  Operating System, Virus Checkers, Firewall, Compression, Backup, Libraries, Translators
• Application Software Examples


  Games, browsers, word-processor, email, photo-editors ...
• Utility Software


  Small programs each with specific purpose often for maintenance of computer
• Utility Software Examples


  Anti-virus software, Disk defragmentation, File managers, Firewalls, Backing up things
• Translator


  Any program that converts source code written in a programming language into machine code (1's and 0's)
• 3 Types of Translators

  Interpreters, Compilers, Assemblers.
• Assemblers


  Assemblers are responsible for converting low level assembly languages directly into machine code. Assembly language specific to each computer.
• Compilers + Interpreters


  Converting high level languages to machine code
• Interpreter


  Take one line of high level language program code and convert it directly into machine code and then runs it. Does this for each line of code.
• Uses of Interpreters


  When debugging a program, it runs through each line of code until it finds an error.
• Disadvantages - Interpreter


  Needs the whole source code each time it translates. Security problem and results in slower execution
• Compiler


  Compiler takes the entire program and converts it into object code. This is then converted to machine code.
• Compiler Advantages


  Takes less time compared to interpreter
• Compiler Disadvantages

  If there is an error, it will not run
• Libraries

  Pre compiled sets of code with lots of subroutines that have already been created for users to use
• Operating System


  Software that manages hardware, software and security of the computer.
• Purposes of Operating System

  Managing Processor - decides which process to do next, handles interruptions to current process
• Purposes of Operating System

  Managing Memory - Allocating and managing memory used
• Purposes of Operating System

  Managing External Devices - Understanding instructions given by external hardware and sending instructions to them
• Purposes of Operating System


  Provides platform for software and utility programs - provides framework for apps to run, e.g. opening and closing files easily, disk defrag, file explorer
• Purposes of Operating System


  Communication using protocols between devices
• Purposes of Operating System

  Denying or saying yes to requests to access resources
• Roles of Operating System

  Providing a User Interface
• Low Level Language


  Assembly language, machine specific
• High Level Language


  Each instruction can be many lines machine code
• Compiler 2

  Source code

  Compiler

  Object Code

  Linker/Loader

  Machine Code