1. 8
    1. 5

      Kinda neat how Microsoft went full circle…

      1978-1980: Unix
      1980-2000: DOS
      2000-2009: Emulated DOS
      2009-2016: PowerShell (plus Emulated DOS)
      2016-today: Linux (plus PowerShell and Emulated DOS)
      
      1. 1

        According to wikipedia, Xenix was first released in 1980 with the last release in 1989.