PART A

1. Difference between RISC and CISC:

o RISC (Reduced Instruction Set Computer): Emphasizes efficiency with
simple instructions that complete in a single cycle. Fewer instructions with
fixed format, using more registers and less memory.
o CISC (Complex Instruction Set Computer): Has a larger set of instructions,
some of which are complex and may take multiple cycles to execute. Aims to
reduce the number of instructions per program, often using variable-length
formats.
2. Functional Units of Computer Organization:
o Control Unit: Manages the execution of instructions by directing other
components.
o Arithmetic Logic Unit (ALU): Performs arithmetic and logical operations.
o Memory Unit: Stores instructions and data.
o Input/Output Units: Facilitate communication between the computer and
external devices.
3. Immediate Addressing Mode with Example:
o Description: The operand is specified directly in the instruction.
o Example: addi $t0, $t1, 10 - Adds 10 (immediate value) to the value in
$t1 and stores the result in $t0.
4. Comparison of Hardwired and Micro-Programmed Control Unit:
o Hardwired: Uses fixed logic circuits to control signals. It’s faster but less
flexible.
o Micro-Programmed: Uses a set of instructions in memory to control signals,
providing flexibility but at slower speeds.
5. Multicycle MIPS and Its Advantages:
o Multicycle MIPS: Breaks down instruction execution into multiple cycles,
improving efficiency by allowing faster operations to complete in fewer
cycles. This approach optimizes performance over single-cycle designs.
6. Memory Organization and Its Importance:
o Definition: Refers to the arrangement of memory (hierarchical structure with
cache, main memory, secondary storage) in a system.
o Importance: Effective organization enables faster access to frequently used
data, reducing latency and improving overall system performance.
7. Memory Hierarchy (Sketch):
o Levels typically include CPU registers, cache, main memory (RAM), and
secondary storage (disk), organized in a pyramid structure to balance speed
and capacity.
8. Advantages of Programmable Array Logic (PAL):
o PALs offer programmable logic for specific applications, providing
customization in digital designs. They are simpler and faster than
Programmable Logic Arrays (PLAs) but less flexible.
9. Characteristics of Cache Memory:
o High-speed: Faster than main memory.
o Temporary storage: Holds frequently accessed data to reduce access time.
o Expensive: Smaller but more costly per byte than main memory.
10. Techniques for Managing Virtual Memory:
o Paging: Divides memory into fixed-size pages, mapping them between
physical and virtual memory.
 o Segmentation: Divides memory into segments based on the logical structure
of programs, each with varying lengths.
11. Difference Between Hardwired and Micro-Programmed Control Unit:
o Hardwired uses fixed logic for control; micro-programmed uses
microinstructions stored in control memory, offering flexibility at the cost of
speed.
12. Cache Memory and Its Importance:
o Definition: High-speed memory that stores frequently accessed data.
o Importance: Reduces access time to data, enhancing CPU performance by
minimizing wait times.
13. Multicycle vs. Single-Cycle Design:
o Multicycle: Instructions take multiple cycles, allowing faster instructions to
complete quickly.
o Single-Cycle: Every instruction takes the same cycle time, leading to
inefficiency for simpler instructions.
14. Major Components of a Computer System:
o Processor (CPU): Executes instructions.
o Memory: Stores data and instructions.
o Input/Output Devices: Interface with the external environment.
o Bus: Data transfer pathways between components.
15. Five Steps in MIPS Instruction Execution:
o Fetch: Retrieve the instruction.
o Decode: Interpret the instruction.
o Execute: Perform the operation.
o Memory Access: Read/write to memory if needed.
o Write Back: Store the result.
16. Examples of Data Transfer Instructions:
o MIPS Example: lw $t0, 4($s1) - Load word from memory.
o sw $t0, 4($s1) - Store word to memory.
17. Concept of Virtual Memory:
o Definition: An abstraction that extends physical memory onto disk, allowing
for larger logical memory spaces.
o Significance: Enables efficient use of physical memory and multitasking.
18. Function of a Programmable Logic Array (PLA):
o A PLA is a customizable logic device, used to implement combinational logic
functions by programming its AND-OR arrays.
19. C Assignment in MIPS Code:
o Expression: f = (g + h) - (i + j)
o MIPS Code:

mips
Copy code
add $t0, $s1, $s2 # g + h
add $t1, $s3, $s4 # i + j
sub $s0, $t0, $t1 # (g + h) - (i + j)

20. State Elements Needed to Store and Access an Instruction:

o Instruction Register (IR): Stores the current instruction.
o Program Counter (PC): Holds the address of the next instruction.
21. Multicycle MIPS Approach:
 o Breaks down each instruction into steps, each requiring one cycle, allowing
faster instructions to finish in fewer cycles.
22. Definition of Instruction Format:
o Structure defining how instructions are encoded, including opcode, operand
fields, and addressing mode.
23. Addressing Mode and Its Significance:
o Defines how the operand’s address is determined, offering flexibility in
accessing data, which improves code efficiency.
24. Main Memory vs. Secondary Memory:
o Main Memory: Fast, volatile, used for executing programs.
o Secondary Memory: Slower, non-volatile, used for long-term storage.
25. Page Fault:
o Occurs when a program tries to access data not currently in physical memory,
triggering a process to retrieve it from disk.
26. Steps in Instruction Cache Miss:
o Identify the missing block.
o Fetch the block from main memory.
o Store it in the cache and continue execution.
27. Segmentation and Its Benefits:
o Memory management technique dividing programs into segments, allowing
flexibility in allocation and protection of logical divisions.