Operating Systems
The operating system is the most fundamental piece of system software; it manages interactions between software and hardware. It takes responsibility for a range of functions including managing processor time, memory management, inputs/outputs, and security.
There are lots of different operating systems. Some are custom written for a particular device, such as a games machine or the guidance system on the International Space Station. Other operating systems are used across a range of devices. The most popular and well-known operating systems are:
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Microsoft Windows
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macOS
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Linux
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Google Android
Role of the Operating System
An operating system (OS) is software that controls the computer’s hardware and software resources. It allows applications to interact with the hardware on a computer. Some software can interact with hardware directly, but most software isn’t written to interact with each particular piece of hardware — the operating system therefore takes care of interacting with the hardware.
The earliest computers did not have an OS. Every program had to include all of the code to run the computer. This made each computer program complex and difficult to create. Since then, operating systems have been developed, with part of their function being to include the code needed to run the computer. This allows for multiple applications to be written more easily to work on a common operating system rather than for individual computers.
Whether or not the OS is custom written for a particular device, or it is a well known OS installed on a wide range of hardware including the device you're using right now, they all perform the same basic functions that keep your computer running smoothly:
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Processor management
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Inputs, outputs, and interrupts
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Memory management
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Security
Processor Management
When you open a program on a computer, the operating system works behind the scenes to make sure that all the hardware is processing the right instructions at the right time. To do this, it starts by finding the appropriate data from the secondary storage and loads it into the main memory.
The Processor is then instructed to execute the processes needed to open that program.
A computer with a single processor Core can only carry out one process at a time; however, the OS will use a scheduler to swap tasks in and out of the processor so that it appears to the user that the computer is carrying out more than one task at the same time. For example, allowing you to listen to a music track from an online streaming service whilst simultaneously using a word processor to complete homework. This is known as multi-tasking. Modern computers often have multiple cores, which makes them more efficient at multi-tasking. However, each core can only carry out one process at a time.
Memory Management
The instructions and data needed for a process have to be available in main memory. To ensure this, the OS runs a memory manager program, which:
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Keeps track of what portions of memory have been allocated
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Maps memory to each process
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Determines how much memory to allocate to each process
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Determines when a portion of memory should be available for a process
File Management and Backing Storage Management
If you've used an operating system such as Microsoft Windows or Mac OS, you will be familiar with the fact that you can perform tasks on files and folders such as:
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Creating
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Renaming
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Moving
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Deleting
These are useful user interface tools that an operating system provides to help the user organize how they would like to manage their files. Behind the scenes, the operating system controls how data is stored and retrieved. The operating system keeps track of where the files are stored on the secondary storage device so that they can be quickly accessed when requested.
Backing storage management
Backing storage refers to any Non-volatile memory storage device. The operating system keeps a directory of where files and programs are stored so that they can be accessed quickly when they are requested and transferred into main memory. Keeping a directory also speeds up storage and saves computational resources, rather than having to search for free space every time a user wants to save a file.