This is a basic course on Computer Organization and Architecture . This course is meant for Engineering Students of Electrical, Electronics & Communication, Computer Science and IT, BSC Students, Diploma Students (Polytechnic), BCA students, MCA students, MTech Students, MS Students. This course is not only beneficial for students to earn credits as a part of their course curriculum but also score well in competitive exams. The Complete Course is divided into Five Sections. Section-1 Covers Differences between Computer Organization and Architecture, Functional Blocks of Computer, Register Organization of CPU ,CPU Organization and Addressing Modes. Section-2 covers Data Representation of Signed numbers, Fixed and Floating Point Numbers and Characters, Computer Arithmetic, Ripple Carry Adder, Carry Look Ahead Adder, Multiplication by Shift & Add, Booth’s Algorithm, Multiplication by Carry Save addition, Restoring Division Algorithm, Non Restoring Division Algorithm. Section-3 Covers Peripheral Devices and their characteristics: Input-Output Subsystems, I/O Device Interface, I/O transfers – Program Controlled, Interrupt Driven and DMA, Privileged and Non-Privileged Instructions, Software Interrupts and Exceptions, Programs and Processes – Role of Interrupts in Process State Transitions, I/O Device Interfaces – SCSI, USB.Section-4 Covers Basic concepts of Pipelining, Throughput and Speedup, Pipeline Hazards, Introduction to Parallel Processors, Concurrent access to Memory and Cache Coherency. Section-5 covers Memory Organization, Memory Interleaving, Concept of Hierarchical Memory Organization, Cache Memory, Cache Size vs. Block Size, Mapping Functions, Replacement Algorithms, Write Policies.