operating system concept

Cards (33)

  • system programs - manage the operations of a computer
  • multitasking systems - run more than one process at a time
  • single-user systems - support one user at a time
  • computer systems consist of - main(user, application programs, operating system, hardware), optional(network, data, procedure)
  • sub process - light weight process, break down complex task into smaller part
  • OS(operating system) - a layer of software that manages and interface all parts of hardware, shields programmers from hardware complexity
  • OS can be defined as - a resource collector, resource manager, a control program, act as an intermediary of computer user and computer hardware
  • OS runs in kernel or supervisor mode to protect user from tampering with hardware
  • OS is regarding as one of the programs that running all time and also called as kernel
  • systems calls are used for communication between OS and application program
  • an initial program runs also called bootstrap program
  • boot up computer start with: POST -> BIOS -> MBR -> GRUB -> kernel -> systemd -> targets
  • BIOS(basic input output system) - serves as a intermediary of OS and computer hardware
  • basic functions of OS - accept command from user, provides desired service for user and user programs, system manager, manages computer resources effectively
  • services provided by OS - program execution, input-output operations, file system manipulation, communication, error detection
  • program execution - loads program in memory, runs the executions either normally or abnormally
  • input-output operations - control input output devices
  • file system manipulation - allow reading, writing, deletion and creating of files
  • communication - manage shared memory for the exchanged of information between processes
  • error detection - correct errors to ensure a consistent state
  • Services to ensure efficient operations in OS - resource allocation, accounting, protection
  • resource allocation - decide the best method to utilize the CPU
  • accounting - calculate performance, cost, resources to ensure efficient operation
  • protection - protect user process and data
  • Classification of Operating Systems
    • Multitasking OS
    • Time Sharing OS
    • RTOS (Real Time OS)
    • Multiprogramming OS
    • Multiprocessing OS
    • Batch OS
    • Single-user OS
    • Multi-user OS
  • Multitasking OS
    Allows simultaneous execution of programs with single processor, example: Microsoft Windows, Linux
  • Time Sharing OS
    Allows multiple simultaneous users, programs are executed bit by bit, example: Unix
  • RTOS (Real Time OS)
    Designed to respond within a certain period, example: weapon system, robots
  • Multiprogramming OS
    Allows more than one active user program stored in memory simultaneously, example: Windows OS
  • Multiprocessing OS
    Has more than one independent processing unit, example: Unix
  • Batch OS
    Only does one thing at a time, example: bank statement
  • Single-user OS
    Allows one user at a time to use computer
  • Multi-user OS
    Allows more than one user to use computer