Operating systems

Operating systems

1. Kernel

   • Loads/Unloads applications from memory
   • Scheduling tasks to run efficiently on the CPU
   • Memory Management
   • File storage to and from secondary storage devices such as the hard drive
   • Data Security

2. User Interface

   • Menu Interface
     • Gives a list of possible options to the user to select from
   • Command Line Interface
     • Uses text-based commands to perform certain tasks
   • Graphical User Interface
     • Uses images and logos that are clickable and reacts to mouse clicks.
   • What user interface's would early personal computers use?

3. Memory Management

   • Programs must be loaded into main memory before they can run.
     • Programs shouldn't be able to interfere with each other
   • Responsible for moving programs between RAM and virtual memory
   • Why does a computer need virtual memory?
     • When RAM runs out, memory is created on the primary hard drive which is much slower. Without this, the program wouldn't be able to run.

4. Multi-tasking

   • Allows more than one program to run at the same time
   • Runs on most personal computers
   • Examples; Windows, OS X, Linux, Android etc.
   • arranges for every process in memory to run in the CPU once they are ready to do so, switching between them to keep them up to date.
   • Why might this be important if someone wanted to take notes on a video using a word document?
     • They wouldn't be able to use both programs at the same time if the OS couldn't multi-task

5. Device Drivers

   • Help hardware connected to the computer communicate with its software and with the user.
   • Every piece of hardware that communicates with the OS needs a device driver.
   • Internal examples; HDD, RAM, GPU, Sound Card etc.
   • External Examples; Printer, monitor, mouse, keyboard etc.
   • Many device drivers are installed with the OS but some devices will need a manual driver install
   • Why wouldn't a device work properly if its drivers weren't installed?

6. User Management

   • Part of the kernel
   • Each user is assigned a set of permissions, a username and password
     • This could be used to restrict certain files, websites, certain software etc.
   • The three common access rights are; Read, Write and Execute
   • How might a student's access rights differ from a teacher's in a school.
     • Students would have access to files they create and a teacher unlocks. They won't be able to access important teaching files or be able to delete or move them. Teachers would have less restrictions on the web.

7. Definition: The core software that controls how a computer operates

8. Examples; Windows, Linux, Unix, IOS and Android.

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