2Main memoryCPUArithmetic/Logic Unit( ALU )Control UnitRegister(s)
3RegistersThe special storage devices in the CPU that CPU uses over and over again for execution of stored-program instructions.There are two types of registers :General purpose registersSpecial purpose registers
4Registers Examples of special purpose registers : PC ( Program Counter )IR ( Instruction Register )MAR ( Memory Address Register )MDR or MBR ( Memory Data Register or Memory Buffer Register )PSW ( Program Status Word )etc.
5CPU Main Memory Control unit Data bus Control bus Address bus R0 R1 MDRIRMARPCALURNControl unitData busControl busAddress busCPUMain Memory
7Main Memory Operations Memory read operationTransfers the content of a specific main memory location to the CPU.The content of the main memory location remains (unchanged).
8Main Memory Operations Memory write operationTransfers a word of information from the CPU to a specific main memory location.Destroys the former content of the main memory location.Memory access timeThe time it takes to perform a memory read or a memory write operation.