austin group bourne shell common open software environment computer computer file computer network computer terminal de facto functional specification hp-ux ibm international electrotechnical commission international organization for standardization linus torvalds linux linux standard base mac os x server ncr corporation nec native posix thread library news release open standard operating system posix powerpc sco openserver sparc software distribution source code tanenbaum-torvalds debate the art of unix programming the open group unix unix-like unixware unix wars usenet vi working group