Evolution of the File Metaphor∗

One of the commonest abstractions in computer systems is that of the file. What clearly began as a metaphor for long-term storage of data has progressed to a fundamental, first-class resource-access mechanism in recent distributed Operating System design. This paper examines four publications related to this development: “Introduction and Overview of the Multics System” [1] and “A General-Purpose File System for Secondary Storage” [2] describe the structure of the Multics system; these were selected because of Multics’ ancestry to Unix, on which most current general-purpose Operating Systems are grounded. Plan 9, a descendent of Unix ideas built largely on its extension of the file metaphor, is also examined in “Plan 9 from Bell Labs” [4]. Finally, Inferno, a commercialized operating system based in large part of the lessons learned from Plan 9, is discussed in “Inferno” [3].