real operating system n. The sort the speaker is used to. People from the BSDophilic academic community are likely to issue comments like "System V? Why don't you use a *real* operating system?", people from the commercial/industrial UNIX sector are known to complain "BSD? Why don't you use a *real* operating system?", and people from IBM object "UNIX? Why don't you use a *real* operating system?" See holy wars, religious issues, proprietary, Get a real computer!