OS Quiz 1

• Program


  A set of instructions that tells the computer what to do
• Software


  A set of interrelated programs
• Types of Software


  • System software
  • Application software
• Types of application software


  • Document production software
  • Spreadsheet software
  • Presentation software
  • Database management software
  • Business software
  • Multimedia software
  • Entertainment software
• System programming


  The act of developing system software
• Types of programming languages

  • Machine language
  • Low-level language/assembly language
  • High-level language
• Types of system programs


  • Operating Systems
  • Language translators
  • Linkers and loaders
• Address binding


  The process of assigning or mapping symbolic references to actual memory locations
• Physical address/absolute address


  The actual main memory location
• Techniques in placing the load module in the main memory

  • Absolute loading
  • Relocatable loading
  • Dynamic run-time loading
• Operating System (OS)


  A system software that allows users or the application programs they are using to interact with the computer hardware in an easy and convenient manner
• Major functions of an OS


  • It creates a virtual machine interface between the user/application program and the hardware
  • It acts as the computer's resource manager or resource allocator
  • It functions as the program launcher
• Main goals of the OS

  • It should make the computer easy and convenient to use
  • It should manage the resources of the computer system to make them more efficient
  • It should execute and control programs
• Bootstrap program


  Stored in the computer's Read-Only Memory (ROM) and is executed upon power on
• Boot Block Loader


  Locates the OS and loads it in the main memory
• Two parts of OS


  • Kernel
  • Shell (Command Interpreter)
• Types of shell


  • Command-Line Interface (CLI)
  • Graphical User Interface (GUI)
• Services provided by the OS


  • Program execution
  • Access to I/O devices
  • File System Management
  • System Access
  • Error handling
  • Communication
• Core components of an OS

  • Process manager (Process scheduler/CPU scheduler)
  • Memory manager
  • File manager
  • I/O manager
• History of OS


  • First Generation - Serial Processing
  • Second Generation - Batch Processing
  • Third Generation - Multiprogrammed Systems
  • Fourth Generation - Time-Sharing Systems
• Types of Computer Systems and their OS

  • Personal computer systems
  • Multiprocessor systems
  • Networked and Distributed Systems
  • Real-time systems
  • Handheld systems
• Computer Hardware components


  • CPU (Central Processing Unit)
  • Main memory/primary memory
  • Secondary memory/Auxiliary memory
  • I/O devices
• Interconnecting bus/system bus


  Serves as the communication link between the four components
• Interrupts


  Signals sent by the devices and programs which are used to get the attention of the CPU and the OS
• Traps/exceptions


  Used to inform the OS when an error occurs and when OS services are needed
• Input-Output Operations


  • Program-controlled I/O
  • Interrupt-driven I/O
  • Direct Memory Access (DMA)
• Protection mechanisms


  • Dual mode operation
  • Memory protection
  • I/O protection
  • CPU protection