This category has information on only RealTime Operating Systems (RTOSs), and closely related material.Realtime systems are not the same as embedded systems. Realtime OSs can be used in general purpose computers, and in embedded types. Some embedded OSs are not realtime, and cannot serve some uses.Why segregate RTOSs so fully? Three clear reasons exist:1) The functional divide between RTOSs and non-RTOSs is large, which profoundly effects design: all OSs must provide logically correct/precise results, but RTOSs must go beyond this and give temporal (time) correctness. RTOSs are the only logical and safe choice for time-critical uses.2) More RTOSs than non-RTOSs (fewer non-RTOSs than RTOSs) are in use, in this solar system at least.3) Directory user needs are different: those seeking information on RTOSs usually need no information on non-RTOSs, and vice versa, those interested in non-RTOSs usually need no information on RTOSs.On this page, links are arranged in three groups and levels: 1) Top group: issues spanning multiple unrelated OSs. 2) Middle group: types or classes of OS, or OSs for which there are more than one instance of an OS of this name/type, an OS family. 3) Bottom group: specific OSs, individual instances; there is only one OS of this name/type.