Operating Systems

Operating Systems

1. Managing Resources

   • File Compression
     • The OS converts the files so the files are stored in a different, small format
       • e.g: eeebbbbuunnss becomes 3e4b2u2n2e
   • Peripherals
     • Input and output devices
       • Keyboard
       • Mouse
       • e.t.c.
     • Drivers
       • software used to map commands to individual peripherals
   • Printing
     • spooling
       • Keeps the document in a queue until the printer is ready
       • The program doesn't need to worry about the printer being unavailable
   • Backing Stores (backups)
     • The OS can automatically make backups
       • Can be to the user's storage devices or a cloud backup (configuration options)
   • Disk Defragmentation
     • re-arranging file fragments on a physical disk surface to improve load times
   • Ram
     • split into “pages”
       • this ensures there is enough memory for each program
       • makes the program think that's all the ram the system has
       • This prevents other programs for viewing what's in the rest of the ram
   • Managing processes
     • Modern processors are faster than the ram and storage
       • Results in resources not being utilized as the other components catch up
   • Multi-Tasking
     • a processor appears to be doing two tasks simultaneously despite the fact that the tasks are being done one by one
       • We can't tell because it's so fast
     • It does this while the rest of the components are catching up
     • this is a very complex task as simply alternating the instructions will result in memory being overwritten
       • The OS has to keep the tasks separate and manage use of the accumulator and memory locations.

2. talks directly to the hardawre

3. allows the software to be written for it rather than the hardware

   • This is important because PCs can have a variety of hardware
   • Software can be compiled for the OS

4. Interface

   • GUI/CLI
     • CLI
       • Included in every OS
       • Command line interface
       • Lightweight and robust
         • Uses few system recorces so is unlikeley to crash
       • controled with a keyboard only
       • Difficult to learn and know whats going on
     • GUI
       • Visual reprosentations of the computers functions
       • Usually controlled by a mouse and keyboard or touch screen
       • Easy to learn and use
       • Can use a lot of system resorces
   • File management
     • Operating systems provide an interface to the user
     • allows for easy file manipulation
       • Copy files Move files Delete files Sort files Search for files
   • System Settings
     • lets the user easily change system settings
     • Enabling or disabling specific hardware
     • Changing the volume
     • Adjusting screen resolution
     • Configuring secondary storage
   • Multi tasking
     • can show multiple applications on screen
       • usually in seperate windows
   • error messages
     • the error is passed to the OS
       • The appropriate message is presented
   • Customization
     • Some provide options to change the colour scheme and desktop background
     • Some allow a completely different desktop environment to be installed.
   • Task management
     • Shows how much resources an application is using
     • Allows the user to easily shut down unresponsive processes