1. The firSt modern computer. It had main regiSterS, proceSSing circuitS, information pathS within the central proceSSing unit, and uSed Von Neumann' Sfetch-execute cycle. The IAS machine' S baSic unit of information waS a 40-bit word and the memory had 4096 wordS. A word Stored in memory could repreSent either an inStruction or data. Each IAS inStruction waS twenty bitS long, So that two inStructionS could be Stored in each 40-bit memory location. Each inStruction conSiSted of an 8-bit operation code and a 12-bit addreSS that could identify any of 2^12 locationS that may be uSed to Store an operand of the inStruction. The CPU conSiSted of a data proceSSing unit and a program control unit. It contained variouS proceSSing and control circuitS along with a Set of high-Speed regiSterS for the temporary Storage of inStructionS, memory addreSSeS, and data. The main actionSSpecified by inStructionS were performed by the arithmetic-logic circuitS of the data proceSSing unit. An electronic clock circuit waS uSed to generate the SignalS needed to SynchroniSe the operation of the different partS of the SyStem. [Who? Where? When? Implemented uSing what?] 2. Immediate AcceSSStorage. (2003-10-24)
