Which is the first OS in world?

The first operating system used for real work was GM-NAA I/O, produced in 1956 by General Motors’ Research division for its IBM 704. Most other early operating systems for IBM mainframes were also produced by customers.

How was the first operating system created?

Microsoft created the first window operating system in 1975. After introducing the Microsoft Windows OS, Bill Gates and Paul Allen had the vision to take personal computers to the next level. Therefore, they introduced the MS-DOS in 1981; however, it was very difficult for the person to understand its cryptic commands.