OS/2

/O S too/ n. The anointed successor to MS-DOS for Intel 286- and 386-based micros; proof that IBM/Microsoft couldn't get it right the second time, either. Often called `Half-an-OS'. Mentioning it is usually good for a cheap laugh among hackers --- the design was so baroque, and the implementation of 1.x so bad, that 3 years after introduction you could still count the major apps shipping for it on the fingers of two hands --- in unary. The 2.x versions are said to have improved somewhat, and informed hackers now rate them superior to Microsoft Windows (an endorsement which, however, could easily be construed as damning with faint praise). See monstrosity, cretinous, second-system effect.