JNTU B.Tech III COMPUTER ORGANIZATION Previous Question Paper (September - 2021 - R16)

A digital computer consists of four primary functional units that work together to process data: the Central Processing Unit (CPU), Memory Unit, Input Unit, and Output Unit. These components are interconnected via a system bus structure consisting of data, address, and control buses.

The CPU acts as the brain of the computer, containing the Arithmetic Logic Unit (ALU) for data processing, the Control Unit (CU) for instruction sequencing and timing, and registers for temporary storage. The Memory Unit stores programs and data currently in use, categorized into primary memory (RAM/ROM). The Input Unit converts external information into machine-readable binary signals (e.g., keyboard, mouse), while the Output Unit translates processed binary data back into human-readable form (e.g., monitor, printer).

Diagram description: The architecture is represented by a central bus system connecting the CPU, Memory, and Input/Output modules. Data flows bidirectionally between the CPU and memory, while control signals originate from the CPU to manage all other units.

Memory reference instructions are used to perform operations involving data stored in the memory. Common examples include:

• AND: Performs a logical AND operation between the content of the accumulator and the data at the specified memory address.
• ADD: Adds the content of the memory location to the content of the accumulator, storing the result in the accumulator.
• LDA (Load Accumulator): Transfers the data from the specified memory location into the accumulator register.
• STA (Store Accumulator): Transfers the content of the accumulator into the specified memory location.
• BUN (Branch Unconditionally): Transfers the program control to the instruction located at the specified effective address, effectively changing the program counter.