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Operating systems - Coggle Diagram
Operating systems
Computer system
Multiprocessor systems
These systems have two or more processors that share physical memory and peripheral devices.
Symmetric multiprocessing
This is the most common for this type of system, where the processors are considered equal and operate independently.
Modern operating systems employ multiprogramming, which allows multiple jobs to be held in memory, thereby ensuring that there is always a task for the CPU to perform.
Time-sharing systems are an extension of this, in which CPU algorithms quickly switch between multiple jobs.
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Cluster systems
It can be defined as the connection of several computers through a local area network.
In cluster systems, machines can perform calculations on data residing on shared storage systems, and these can continue even if members of the cluster fail.
Distributed systems allow users to share available resources through a series of geographically dispersed hotspots, using a computer network.
Main Memory
Programs are located in main memory, in addition to being the only storage area that the processor can access
It is a matrix of words or bytes, with millions of different positions, each word in memory has its own address. But it is volatile since when disconnected it loses its data.
Most systems offer internal storage as an extension of the main memory, this "second memory" is capable of storing huge amounts of data permanently and the most common is the magnetic disk.
Storage systems are organized in a hierarchy based on cost and speed. As you go down the hierarchy, the cost per bit decreases as access time generally increases.
What is it
It is a software that manages the computer hardware and adds an environment to run programs. Thanks to this, the most important thing is the interfaces that it provides to the user.
Operation
The operating system must ensure the correct operation of the computer system. That is why the hardware supports two working modes: user mode and kernel mode.
When you start a user-mode application, Windows creates a process for it. This process provides the application with a private virtual address space and a table of private handles. Because each application's virtual address space is private, an application cannot modify another application's data. Each application runs in isolation, ensuring that if it crashes, it does not affect other applications or the operating system.
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There are many instructions like I/O instructions and wait instructions, they are privileged instructions and can only be executed in kernel mode.
The memory must be protected against user modifications, thanks to which there is a timer that prevents infinite loops. Together these features are used by the system for correct operation.
A process or job is the fundamental unit of work in an operating system. Process management includes the creation and deletion of processes and provides mechanisms for them to communicate with each other. The memory unit is managed by keeping track of its parts and by the memory unit, which is responsible for the dynamic allocation and release of space in the memory unit. As mentioned, it is responsible for the space and for representing files and directories.
Operating systems must also take care of the protection and security of the system itself and its users. This includes access to the resources of the system by processes or users, and therefore must have security measures against internal and external attacks.
There are various types of computer systems that serve specific purposes. These include real-time operating systems designed for embedded environments such as consumer devices, automobiles, and robotic equipment. These systems have certain restrictions or the system will fail.