What is operating system?

A computer’s operating system is the software that actually makes it function.
All of the programs we utilize are made possible by this software.
The operating system arranges and manages the hardware.
OS serves as an interface between the hardware of the computer and the application programs.
Examples include Mac OS, Linux, Unix, and Windows.

What Operating System does?

Basic functions of an operating system include memory allocation and control, system request prioritization, input and output device control, networking assistance, and file system management.

Explain the structure of OS

There are four layers in the OS structure:
1. Hardware includes CPU, main memory, I/O devices, and other components.
2. Operating System software: File management, I/O control, memory management, and process management techniques are all included in software.
3. System programs: Compilers, assemblers, linkers, and other components make up this layer.
4. Programs for applications: This depends on what the user needs. For example, bank database administration, railway reservation systems, etc.

Discuss the evolution of OS

There were seven main stages in the development of operating systems, and six of them profoundly altered how people used computers: batch processing, timesharing, open shop, personal computing, distributed systems, and multiprogramming.
The seventh step involved developing and demonstrating the fundamentals of concurrent programming in model operating systems.

Major phases	Technical innovations	Operating systems
Open shop	The idea of OS	IBM 701 open shop (154)
Batch processing	Tape batching, FIFO scheduling	BKS system (1961)
Multi programming	Processor multiplexing, indivisible operations, demand paging, I/O spooling, priority scheduling, remote job entry	Atlas supervisor (1961), Exec II system (1966)
Timesharing	Simultaneous user interaction, online file sharing systems	Multics file system (1965) Unix(1974)
Concurrent programming	Hierarchical systems, extensible kernels, [parallel programming concepts, secure parallel languages	RC 4000 system (1969), 13 Venus system (1972), 14 Boss 2 system (1975)
Personal computing	Graphics User Interfaces	OS 6 (1972) Pilot system (1980)
Distributed systems	Remote servers	WFS file server (1979) Unit United RPC (1982) 24 Amoeba system (1990)

Types of OS:

Operating System can also be classified as,-

• Single User Systems
• Multi User Systems

Single User Systems:

• Provides a platform for only one user at a time.
• They are popularly associated with Desk Top operating system which run on standalone systems where no user accounts are required.
• Example: DOS

Multi-User Systems:

• Provides regulated access for a number of users by maintaining a database of known users.
• Refers to computer systems that support two or more simultaneous users.
• Another term for multi-user is time sharing.
• Ex: All mainframes and  are multi-user systems.
• Example: Unix

Explain the difference between a process and a thread.

Think of a process as a program you run, and a thread as a small part of that program. Multiple threads can work together in one process.

What is multitasking, and how does an operating system achieve it?

Multitasking means your computer can do many things at once, like running apps simultaneously. The operating system helps by sharing the CPU’s time among these tasks.