OS/2 dies next year, Mac OS withers away within five years unless IBM Corp adopts it, and Microsoft Corp wins a monopoly of the desktop with Windows95. That is the gloomy prognostication of an unpublished Dataquest Inc report that has been seen by the Wall Street Journal. The report believes Apple Computer Inc and IBM will be swamped by a successful marketing blitz this August by Microsoft on behalf of Windows95, and predicts that IBM will kill OS/2 for the desktop sometime next year, while Apple’s share of the total operating-system market will drop by more than 50% over the next five years to a perilous 5%, at which point software developers would defect in droves. Dataquest analysts recommend that to forestall this, IBM should adopt and market Mac OS for its Power Personal Systems.The report’s writer forecasts that Windows95 will achieve shipments of 33.5m units in the fourth quarter alone, and that by the end of 1999, about 200m users will be on Windows 95 or its successors.