Operating Systems

Types of Operating System

By the end of the lesson you should be able to : Classify operating systems according to numbers of users, user interface and number of tasks Describe operating systems in each of the above classes.  

Classification According to Number of Users

  • Multi-user OS  -  supports more than one user at a time. Examples are network OS like windows and Linux
  • Single-User OS- Runs one user program at a time and is designed for use by only one person. Examples are most of the Operating Systems used in cell phones.

Classification According Number of Tasks

  • Single-task operating system - allows processing of one program in the main memory at a time. Examples are MS. Disk Operating System .
  • Multi-tasking Operating System  - allows many programs to run at a time. Priority scheduling is used by the operating system to allocate a slice of CPU time to the programs.

Classification According to User-interface

  • Commandline Operating System - The user interacts with the computer by typing commands at the command prompt. It is not user friendly as the user has to learner and recall commands. Examples are Ms, DOS .
  • Graphical User Interface Operating System- The user interacts with the computer by use mouse pointer, windows , menus and icons. They are user friendly as icons remind the user of various commands. Examples are Linux , Windows Mac OS .
  • Menu Driven OS - was an improvement on commamdline OS e.g MS. DOS  was improved to give DOS-shell. Menu driven OS reduce the pain of recalling commands by give the user options to choose from.