Program-controlled data processor having two simultaneously operating identical system units

Claim 1

In program-controlled data processing apparatus wherein central processing system units are in communication with central storage system units, at least two identically constructed processing units having data terminals thereon connected to operate in a parallel manner with the data terminals of at least two identically constructed central storage units, and at least two identically constructed central storage units having data terminals thereon connected to operate in a parallel manner with the data terminals of at least two of said identically constructed processing units, such that the respective system units perform identical functions concurrently and in synchronism and wherein bits of information supplied by those of said system units operating in parallel are compared and in case of malfunction or disturbance a fault indicating signal is produced, the improvement comprising: a plurality of comparator circuit means, at least one of which is associated with each said system unit and is connectable to the data terminals of that system unit, each said comparator means including switching means for selectively additionally connecting that comparator means to others of said system units being operated in parallel.