Avoid Argument by Restatement

• The primary reason that Therac-20 killed far fewer people than Therac-25 was the fact that Therac-20 had hardware interlocks while Therac-25 did not. Thus, while the hardware interlocks on Therac-20 prevented deaths, Therac-25 had no similar mechanism. The hardware interlocks made Therac-20 safer than Therac-25.