Computer architecture and organization

Basic Terminology • Control Unit – A control unit (CU) handles all processor control signals. It directs all input and output flow, fetches the code for instructions and controlling how data moves around the system. • Arithmetic and Logic Unit (ALU) – The arithmetic logic unit is that part of the CPU that handles all the calculations the CPU may need, e.g. Addition, Subtraction, Comparisons. It performs Logical Operations, Bit Shifting Operations, and Arithmetic Operation. Figure – Basic CPU structure, illustrating ALU • Main Memory Unit (Registers) – • Accumulator: Stores the results of calculations made by ALU. • Program Counter (PC): Keeps track of the memory location of the next instructions to be dealt with. The PC then passes this next address to Memory Address Register (MAR). • Memory Address Register (MAR): It stores the memory locations of instructions that need to be fetched from memory or stored into memory. • Memory Data Register (MDR): It stores instructions fetched from memory or any data that is to be transferred to, and stored in, memory. • Current Instruction Register (CIR): It stores the most recently fetched instructions while it is waiting to be coded and executed. • Instruction Buffer Register (IBR): The instruction that is not to be executed immediately is placed in the instruction buffer register IBR. • Input/Output Devices – Program or data is read into main memory from the input device or secondary storage under the control of CPU input instruction...

Computer Organization and Architecture is the study of internal working, structuring, and implementation of a computer system. Architecture in the computer system, same as anywhere else, refers to the externally visual attributes of the system. Externally visual attributes, here in computer science, mean the way a system is visible to the logic of programs (not the human eyes!). Organization of a computer system is the way of practical implementation that results in the realization of architectural specifications of a computer system. Contents • 1 How it came along • 1.1 The beginning • 1.2 Von Neumann architecture • 2 Rapid restructuring of Organization • 3 IAS Computer • 4 Memory Organisation • 5 Input/Output Unit • 6 Control Unit • 7 RISC/CISC/Supersclass • 8 References How it came along [ | ] The history of computer systems, in the strict sense of the name, will date back to as back as the basic need for computation among humans. We, however, are more concerned with architecture and organization of Electronic computer systems only as 'the computing systems' before this had very vague (or at least different!) representation of these terms in their construction. The beginning [ | ] The first among the electronic computers was The ENIAC, designed by John Mauchly and J. Presper Eckert. This, although a great achievement altogether, was not of much importance in front of standards of Architecture and organization. The programming of this giant machine required manual change...

So there was this question in one of my class tests. It may seem very simple and straight-forward, but I am unable to catch up with its meaning or explanation. I have referred my textbook of COMPUTER ORGANIZATION AND ARCHITECTURE by William Stallings. But that has just got me more confusing. The definitions according to my textbook are: Computer architecture refers to those attributes of a system visible to a programmer or, put another way, those attributes that have a direct impact on the logical execution of a program. Computer organization refers to the operational units and their interconnections that realize the architectural specifications. I even referred to some websites which students at our university, if not the whole country, mainly depend on, but that didn't me help either. The question is to mark which of the following is/are true: • Computer Organization refers to the design of functional blocks in a computer system. • Computer Organization is responsible to integrate functional blocks in a computer system. • Computer Architecture refers to the design of components and functional blocks in a computer system. • Computer Architecture concerns with the integration of functional blocks to build a computer system. My marking was 2nd and 3rd option. My explanation about the same was: architecture would include designing of a structure while organization would be, well, the very English definition of how things are organized in a particular manner. I know this may ...