Alexis de Tocqueville Institution it called "hybrid" source models, in which true open source code is mixed with proprietary code, with the result that intellectual property rights are nullified. To illustrate potential problems with this approach, the book cited the case of Linus Torvalds, creator of Linux. It claimed Torvalds used source code taken from Minix, a small Unix-like operating system used in teaching computer science, to create Linux 0.01, on the theory that no mere student could write an entire Unix-like kernel single-handedly — although writing a kernel of similar size and capabilities is a standard part of many computer science degrees. These
Operating system Digital Equipment Corporation developed many operating systems for its various computer lines, including TOPS-10 and TOPS-20 time sharing systems for the 36-bit PDP-10 class systems. Before the widespread use of UNIX, TOPS-10 was a particularly popular system in universities, and in the early ARPANET community. RT-11 was a single-user real-time OS for the PDP-11 class minicomputer, and RSX-11 was the corresponding multi-user OS. From the late 1960s through the late 1970s, several hardware capabilities evolved that allowed similar or ported software to run on more than one system. Early systems had utilized microprogramming to implement features on their systems in