496
OS market share in Top 500 supercomputers
(feddit.org)
From Wikipedia, the free encyclopedia
Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
Community icon by Alpár-Etele Méder, licensed under CC BY 3.0
Early computers didn't have operating systems.
You just plugged in a punch card or tape with the program you want to run and the computer executed those exact instructions and nothing else.
Those programs were specifically written for that exact hardware (not even for that model, but for that machine).
To boot up the computer, you had to put a number of switches into the correct position (0 or 1), to bring its registers in the correct state to accept programs.
So you were the BIOS and bootloader, and there was no need for an OS because the userspace programs told the CPU directly what bits to flip.