Linus Torvalds both companies went public and Torvalds's share value temporarily shot up to roughly US$20 million. His personal mascot is a penguin nicknamed Tux, which has been widely adopted by the Linux community as the mascot of the Linux kernel. Although Torvalds believes "open source is the only right way to do software", he also has said that he uses the "best tool for the job", even if that includes proprietary software. He was criticized for his use and alleged advocacy of the proprietary BitKeeper software for version control in the Linux kernel. Torvalds subsequently wrote a free-software replacement for BitKeeper
Disk operating system to be installed inside the computer. Some disk operating systems were the operating system for the entire computer system. Disk operating system A disk operating system (abbreviated DOS) is a computer operating system that can use a disk storage device, such as a floppy disk, hard disk drive, or optical disc. A disk operating system must provide a file system for organizing, reading, and writing files on the storage disk. Strictly speaking, this definition does not apply to current generations of operating systems, such as versions of Microsoft Windows in use, and is more appropriately used only for older generations