Free as in Freedom the Linux kernel, Torvald's willingness to borrow GCC for the purposes of his own free software operating system indicated a certain obligation to let other users borrow back. As Torvalds would later put it: "I had hoisted myself up on the shoulders of giants." Not surprisingly, he began to think about what would happen when other people looked to him for similar support. Andrew Leonard in "Salon" complimented the amount of new information Williams reveals about Stallman, given the amount of material already published. He describes the book as a "nuanced, detailed picture of Stallman". In "Computer User", Jende Huang
Operating system existing hardware production. MCP is still in use today in the Unisys ClearPath/MCP line of computers. UNIVAC, the first commercial computer manufacturer, produced a series of EXEC operating systems. Like all early main-frame systems, this batch-oriented system managed magnetic drums, disks, card readers and line printers. In the 1970s, UNIVAC produced the Real-Time Basic (RTB) system to support large-scale time sharing, also patterned after the Dartmouth BC system. General Electric and MIT developed General Electric Comprehensive Operating Supervisor (GECOS), which introduced the concept of ringed security privilege levels. After acquisition by Honeywell it was renamed General Comprehensive Operating System (GCOS).