What was the first of operating system?

Answer 1

Most first generation computers had no operating system. When they did, it was usually just something called a Batch Monitor, all it did was sequence through several jobs one at a time that had been submitted in a batch. The computer companies saw no need for any form of operating system, so the machine's users had to write them all themselves. It was not until the second generation computer that computer companies supplied operating systems for their computers and the earliest of these were simply adaptations of operating systems written by users of first generation computers with a few extensions.