Linus Torvalds Second Lieutenant, with the role of a ballistic calculation officer. Torvalds bought computer science professor Andrew Tanenbaum's book "", in which Tanenbaum describes MINIX, an educational stripped-down version of Unix. In 1990, he resumed his university studies, and was exposed to UNIX for the first time, in the form of a DEC MicroVAX running ULTRIX. His M.Sc. thesis was titled "Linux: A Portable Operating System". His interest in computers began with a Commodore VIC-20, at the age of 11 in 1981, initially programming in BASIC, but later by directly accessing the 6502 CPU in machine code. He did not make
Operating system device drivers to the operating system's kernel, where they can be passed onto applications, or carried out directly. Security of operating systems has long been a concern because of highly sensitive data held on computers, both of a commercial and military nature. The United States Government Department of Defense (DoD) created the "Trusted Computer System Evaluation Criteria" (TCSEC) which is a standard that sets basic requirements for assessing the effectiveness of security. This became of vital importance to operating system makers, because the TCSEC was used to evaluate, classify and select trusted operating systems being considered for the processing, storage