Source
Operating system
The role of operating systems, key functions and types of OS.
The operating system is the interface between applications and computer hardware. It manages all the machinery: processes, memory, files, devices, networking and security.
Key OS Responsibilities
- Process and thread scheduling (CPU scheduling).
- Memory and address space management.
- File systems, data access and buffering.
- Managing devices through drivers.
- Network stack and basic security (permissions, isolation, accounts).
User space and kernel space
User space isolates applications, and kernel space contains the kernel and drivers. The transition between them occurs through system calls.
User space vs kernel space
Select a step to see where work is executed and how the OS interacts with hardware.
User space
Kernel space
Device drivers
Device drivers translate OS requests into hardware commands.
Hardware
CPU, RAM, disks, network, peripherals.
Active step
Click “Start” to walk through the program execution flow.
How user programs are executed
Process life cycle
- Loading the executable file and creating a process.
- Allocation of virtual address space and memory pages.
- The kernel scheduler issues a CPU quantum and switches the context.
- System calls transfer execution to kernel space for I/O.
- Interrupts return the result and control to user space.
The role of drivers
- The driver receives a request from the kernel (for example, writing a file or sending a packet).
- Translates a universal OS request into device controller commands.
- Handles interrupts and notifies the kernel that the operation has completed.
Common operating systems
Android
Smartphones and mobile devices.
- Mobile OS based on Linux
- Widely used on smartphones
Windows
Desktops, corporate workstations, games.
- Wide compatibility with software and drivers
- Standard in an office environment
iOS / iPadOS
Apple mobile devices and tablets.
- Tight security model
- Deep hardware optimization
macOS
Apple computers, development, creative industries.
- UNIX-like base
- Tight integration with the Apple ecosystem
Linux
Servers, clouds, containers, desktops.
- Open source and many distributions
- Dominates server and supercomputing environments
Embedded / Real-time OS
Embedded systems, industry, automotive.
- Deterministic Delays
- Examples: QNX, VxWorks, RIOT, TinyOS
Practical conclusion
Understanding how the OS manages resources helps design applications to meet real hardware constraints: CPU scheduling, memory limits, storage features, and I/O costs.