<P> In 1986, Maurice J. Bach, of AT&T Bell Labs, published The Design of the UNIX Operating System . This definitive description principally covered the System V Release 2 kernel, with some new features from Release 3 and BSD . </P> <P> In 1987, MINIX, a Unix - like system intended for academic use, was released by Andrew S. Tanenbaum to exemplify the principles conveyed in his textbook, Operating Systems: Design and Implementation . While source code for the system was available, modification and redistribution were restricted . In addition, MINIX's 16 - bit design was not well adapted to the 32 - bit features of the increasingly cheap and popular Intel 386 architecture for personal computers . In the early nineties a commercial UNIX operating system for Intel 386 PCs was too expensive for private users . </P> <P> These factors and the lack of a widely adopted, free kernel provided the impetus for Torvalds' starting his project . He has stated that if either the GNU Hurd or 386BSD kernels had been available at the time, he likely would not have written his own . </P> <P> In 1991, while studying computer science at University of Helsinki, Linus Torvalds began a project that later became the Linux kernel . He wrote the program specifically for the hardware he was using and independent of an operating system because he wanted to use the functions of his new PC with an 80386 processor . Development was done on MINIX using the GNU C compiler . The GNU C Compiler is still the main choice for compiling Linux today . The code however, can be built with other compilers, such as the Intel C Compiler . </P>

On which date linux kernel was first released in public