IS211

• Computers have two fundamental components: Hardware and Software
• User interface: application program that accepts user input indicating what to do, forwards this input to the OS for completion, and gives results back to the user. Can be a command line prompt or a graphical user interface (GUI)
• Graphical user interface (GUI)


  • Component of an OS that the user can interact with using the keyboard or the mouse
  • Consists of menus, dialog boxes, and symbols (known as icons)
• Two types of programs are executed on a computer: Applications (apps) and Operating system (OS) software
• Device driver: software containing instructions that the OS uses to control and interact with a specific device
• Hardware components

  • Processor (CPU)
  • Physical memory (RAM)
  • Hard disk and solid state drives
  • CD and DVD drives
  • Flash memory card readers (SD cards)
  • Sound cards
  • Video cards
  • Network adapter cards
  • Ports
  • Mainboards (motherboards)
• System services

  • Printing
  • Scheduling programs
  • Gaining network access
• Role of operating system software

  Applications take the information the user supplies and relay it to the operating system, which uses the computer hardware to carry out the requests
• Software types

  • Open source: Software in which the source code and software can be obtained free of charge and optionally modified
  • Closed source: Software in which the source code is not available; usually costly and referred to as commercial software
  • Freeware: Closed source software given out free of charge, sometimes referred to as freemium software
  • Shareware: Closed source software initially given out free of charge but requires payment after a certain period of use
• Linux kernel

  • Written almost entirely in the C programming language
  • Software can be used to modify appearance of Linux, but the kernel is common to all Linux
  • Understanding Linux kernel version numbers is important to decide which version is appropriate
  • Good understanding of system hardware is important in deciding which kernel version to use
• Open Source Software (OSS)

  • Freely developed and continuously improved by a large community of software developers
  • Source code is a list of instructions that a software developer writes to make up a program
  • Format and structure of source code follows rules defined by the programming language in which it was written
• Linux Operating System


  • Multiuser and multitasking OS
  • Ability to manage thousands of tasks at the same time
  • Allows multiple users to access the system simultaneously
• Linux is an OS used to run a variety of applications on different hardware components
• Linux kernel is the core component of the Linux Operating System
• Identifying Kernel Versions

  1. Major number indicates major revision to Linux kernel

  2. Minor number indicates minor revision and stability of Linux kernel

  3. Production kernel is thoroughly tested and stable

  4. Developmental kernel is not fully tested and implies instability

  5. Revision number indicates most current changes to the version
• Implications of OSS software development

  • Software is developed rapidly through collaboration
  • Software bugs are promptly fixed
  • Software features evolve quickly based on users’ needs
  • Perceived value of the software increases because it is based on usefulness, not on price
• Artistic license

  • Ensures source code is freely available
  • Original author has some control over changes
• Types of Open Source Licenses

  • GNU Public License (GPL)
  • Artistic license
• Most closed source software is sold commercially
• Freeware is distributed free of charge; source code is not available
• Support for closed source software may end
• Linux Advantages

  • Risk reduction
  • Meeting business needs
  • Stability and security
  • Flexibility for different hardware platforms
  • Ease of obtaining support
• Software emulators available for Linux
• Software version may be retired
• Common software available for Linux
• Database software available for Linux
• Customers using a closed source OS must rely on the vendor to fix any bugs
• Code is freely available and scrutinized by many developers
• The collaborative open source approach to testing and fixing bugs increases the stability of Linux
• Desktop productivity software available for Linux
• Can choose to install only software packages needed
• Linux supports several programming languages, such as shell and PERL scripts to customize or automate tasks
• Frequently asked questions (FAQs)
• Shareware is initially free, but requires payment after a period of time or for use of certain features
• Changes in the market or customer needs may cause companies to change software frequently
• Types of software

  • Freemium software
  • Shareware
  • Closed source software that is initially given out free of charge but that requires payment after a certain period of use
• Types of Closed Source Licenses

  • Freeware
  • Shareware
• GNU Public License (GPL)

  • Developed by the Free Software Foundation (FSF)
  • Stipulates that the source code of any software published under its license must be freely available
  • Users who modify the source code must also redistribute the modified code freely
• Usually bears label of manufacturer
• OSS products offer the opportunity to maintain and change the source code