Introduction to Operating System

Virtualisation

Here, OS takes a physical resource and transforms it into a more general and easy-to-use virtual form. We call it a “Virtual Machine”. The system creates an illusion with a massive number of virtual CPUs, which helps run multiple programs simultaneously though we got only one processor ~ “Virtualizing the CPU”. The OS maps virtual address space onto the physical memory of the system. This is done so that a memory reference within one running program does not affect the address space of other processes, making the multiple programs run smoothly simultaneously. In reality, physical memory is a shared resource managed by OS. Thus OS “virtualise memory”.

Concurrency

After virtualising the CPU and memory of the system, now OS does multiple computations simultaneously. This is evident in multi-threaded programs. As this blog aims to give you a basic and straightforward idea of OS, we don’t go deep with this.

Persistence

After running the programs, now OS wants to store the data persistently for the purpose it needs hardware and software. Hard disk and Solid-state drives as hardware help OS store data. As much as storing the information is essential, managing those stored data is more important. There comes software to fulfil this need and enables sharing the stored data with other systems.

Goal Designing

OS virtualises, handles issues related to concurrency and stores data persistently. We want to have some goals to help focus our design and implement it accordingly. Finding the right set of trade-offs is a key to building systems. Goals must be like maximising the system’s performance and minimising the OS’s overheads, protection between applications installed and the OS, energy-efficient and mobility. These types of goals help to build a massive successful system.

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