JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II DIGITAL LOGIC DESIGN AND COMPUTER ORGANIZATION Previous Question Paper (October - 2020 - R13)

The operational concepts of a digital computer are centered on the Von Neumann architecture, which involves the following fundamental processes:

1. Input: The computer receives raw data and instructions from external devices (e.g., keyboard, mouse) and stores them in the memory.
2. Processing: The Central Processing Unit (CPU) performs arithmetic and logical operations. It fetches instructions from memory, decodes them, and executes the required operations.
3. Storage: Memory units (Primary and Secondary) store data and programs. The CPU interacts with the memory to read operands and write results.
4. Output: After processing, the computer presents the results to the user through output devices like monitors or printers.
5. Control: The Control Unit (CU) acts as the brain, coordinating all activities by generating timing and control signals to manage the flow of data between components.

A bus structure is a communication system that transfers data between components inside a computer or between computers. The key elements and types are:

1. Data Bus: Carries the actual data being processed between the CPU, memory, and I/O devices. It is bidirectional.
2. Address Bus: Carries the memory address from the CPU to memory or I/O devices to identify where data should be read from or written to. It is unidirectional.
3. Control Bus: Transmits command signals (e.g., Read, Write, Interrupt) from the CPU to other components to synchronize operations.

Common bus structures include:

• Single-Bus Structure: All units (CPU, Memory, I/O) are connected to a single common bus. While simple, it creates a bottleneck as only one transfer can occur at a time.
• Multiple-Bus Structure: Uses multiple buses to allow simultaneous data transfers, significantly improving system throughput and reducing contention between the CPU and I/O devices.