Computer Architecture and Design Interview Questions and Answers

1 :: What are the basic components in a Microprocessor?

1)address lines to refer to the address of a block

2)data lines for data transfer

3)IC chips 4 processing data

Is This Answer Correct?    11 Yes 2 No

2 :: What is MESI?

The MESI protocol is also known as Illinois protocol due to its development at the University of Illinois at Urbana-Champaign and MESI is a widely used cache coherency and memory coherence protocol.
MESI is the most common protocol which supports write-back cache. Its use in personal computers became widespread with the introduction of Intel's Pentium processor to "support the more efficient write-back cache in addition to the write-through cache previously used by the Intel 486 processor"

Is This Answer Correct?    2 Yes 0 No

3 :: What are the different hazards? How do you avoid them?

There are situations, called hazards, that prevent the next instruction in the instruction stream from executing during its designated clock cycle. Hazards reduce the performance from the ideal speedup gained by pipelining.


There are three classes of Hazards:
1. Structural Hazards: It arise from resource conflicts when the hardware cannot support all possible combinations of instructions simultaniously in ovelapped execution.

2. Data Hazards: It arise when an instruction depends on the results of previous instruction in a way that is exposed by the ovelapping of instructions in the pipeline.

3. Control Hazards: It arise from the pipelining of branches and other instructions that change the PC.

How to Avoid Hazards:
1. Structural Hazard: This arise when some functional unit is not fully pipelined. Then the sequence of instructions using that unpipelined unit cannot proceed at the rate of one one per clock cycle. Another common way that it may appear is when some resources are not duplicated enough to allow all combination of instructional the pipeline to execute. So by fully pipe lining the stages and duplicating resources will avoid structural pipeline.

Is This Answer Correct?    1 Yes 0 No

4 :: What is the pipelining?

A technique used in advanced microprocessors where the microprocessor begins executing a second instruction before the first has been completed. That is, several instructions are in the pipeline simultaneously, each at a different processing stage.

Is This Answer Correct?    3 Yes 1 No

5 :: Cache Size is 64KB, Block size is 32B and the cache is Two-Way Set Associative. For a 32-bit physical address, give the division between Block Offset, Index and Tag.

64k/32 = 2000 blocks
2 way set assoc- 2000/2 = 1000 lines-> 10 bits for index
32B block-> 5 bits for block offset
32-10-5= 17 bits for tag

Is This Answer Correct?    3 Yes 1 No