What & How & Why

Linus Benedict Torvalds: a Finnish software engineer who is the creator and principal developer of the Linux kernel.

Torvalds created three small programs: one can print “A”, other can print “B”, the third one can switch between the first and second program by some custom logicals. He put all of these three programs into x86386 and run them together; then he got a result like: “ABABABAB…”. That being said, x86386 is able to run multitasking base on the hardware.

Reference: Minix
Programming language & Complier: C & GCC
Compatible: Torvalds hope linux could be compatible with Unix so that people who use linux can also run programs that developed on Unix. So he followed POSIX standard to develop the next version of linux.