Don't remember how many cycles (lots) were consumed, nor the frequency with which the mode change was needed in practical OS but - do recall enough discussions of The Problem then -

Such that in usual 20/20 -- we have to ask! How Could IBM have so doggedly pursued development, in the face of an obviously fatally flawed device? *D'Oh!*

Chance. Dumbth. - the real 'movers and shakers' of our world of illusions!



A.