Inferno was, in some sense, the successor to Plan 9, as it was developed by the same people using the experience gained from Plan 9 and with similar goals in mi

Inferno was, in some sense, the successor to Plan 9, as it was developed by the same people using the experience gained from Plan 9 and with similar goals in mind. For example, the protocol underlying the "everything is a file" abstraction in 4th edition Plan 9 is 9P2000; this is basically identical to the Styx protocol found in Inferno, save for the name. It wouldn't surprise me if the author was familiar with Plan 9 but, because of only relatively cursory research, assumed that Inferno had succeeded or obseleted it in some way.