Computer Organization PCC-CS-302 Organizer: Operating Systems, Computer Arithmetic, Control Unit, Bus Structure etc.

The document is a textbook chapter overview and compilation of questions and answers related to **Computer Organization**. **Key Topics Covered:** * **Introduction to Computer Organization and Architecture:** Definitions of computer organization and architecture, parts of a digital computer (CPU, Memory Unit, I/O Unit), and the structure and functions of these units. It also discusses the Von Neumann Concept (stored-program concept). * **Operating Systems (O.S.):** Defines an O.S. as an intermediary between the user and hardware and lists its functions, such as resource allocation and acting as a control program. * **Computer Arithmetic:** Covers topics like Booth's multiplication algorithm, restoring and non-restoring division, carry look-ahead (CLA) adder vs. ripple carry adder, IEEE 754 floating-point format, and guard bits. * **Instruction Set and Addressing Modes:** Explains different instruction formats (three-address, two-address, one-address, zero-address) and addressing modes like Base-Index addressing and PC-relative addressing. It also compares RISC and CISC architectures. * **Control Unit:** Describes the instruction cycle (fetch and execution), and differentiates between hardwired and micro-programmed control units. * **Memory Organization:** Details the memory hierarchy (Auxiliary, Main, Cache, CPU), types of RAM (Static and Dynamic), and the concept of virtual memory. It also includes cache memory mapping schemes (direct, associative, set-associative) and 'write' policies (write-through and write-back). * **Bus Structure:** Discusses common bus systems and their construction using multiplexers or tri-state buffers. It also distinguishes between system bus and I/O bus. * **Input-Output Organization:** Explains Direct Memory Access (DMA), interrupts (external, internal, software, vectored, non-vectored), I/O methods (programmed I/O vs. interrupt-initiated I/O), and pipeline architecture and hazards.