00291nam a2200121 a 450000500170000002000150001708200130003210000210004524500280006626000420009430000200013663000130015620251202164228.0  a0192177419  a004bSTE  astevens, Richard  aUnderstanding computers  aOxfordbOxford University Pressc1986  a218.b24cm.cHB  aComputer