PenPoint BLIS BP2 VS2 JONELTA CTOS EPOC32 TENEX timesharing QQDOS Multiprogramming Ultrix X86 JiffyDOS Tebby HDOS DTSS UX 80186 RDOS PRIMOS LightNet LynxOS operating nderson Vanderson DECsystem Multitasking MVS BESM RTOS QQNX CTSS mainframes mainframe Meshchyora LanceR KRONOS