Provides services that computer needs, manages the running of the hardware and other software [allowing for communication]
Eg. - Utility Programs and Operating Systems
Provides services that a user needs, allows the user to perform a task, providing a service to the user
Word Processor - Creation of documents
Spreadsheet - Calculations on data
Database - Store and search sets of data
Web browser - View and navigate websites
Firmware - Stored in ROM, loaded when computer starts
Bootstrap - First commands loaded, checks hardware and loads firmware
Graphical User Interface - Has windows, icons, menus and pointers
Command Line Interface - Enter text as commands
Natural Language Interface - Text commands or speak commands, os analyzes the input and performs