Western Digital Senior Firmware Engineer Interview Questions and Answers

String is immutable while StringBuffer is mutable.

• StringBuffer is faster for concatenation operations.

• StringBuffer has methods to modify the string.

• StringBuffer is thread-safe while String is not.

• StringBuffer has a larger memory footprint than String.

Predicate is a functional interface that takes an argument and returns a boolean value. Supplier is a functional interface that takes no argument and returns a value.

• Predicate is used for filtering or testing a condition on an object.

• Supplier is used for providing a value or generating a value.

• Predicate takes an argument and returns a boolean value based on the condition.

• Supplier takes no argument and returns a value.

• E...read more

The refrigeration cycle is a thermodynamic process that removes heat from a designated area to lower its temperature.

• 1. Evaporation: Refrigerant absorbs heat from the environment, turning from liquid to gas.

• 2. Compression: The gas is compressed, increasing its pressure and temperature.

• 3. Condensation: The hot gas releases heat to the surroundings, condensing back into a liquid.

• 4. Expansion: The liquid refrigerant expan...read more

Chillers and VRF systems differ in design, application, and efficiency, with various compressor types influencing performance.

• Chillers are centralized cooling systems, while VRF systems are decentralized and allow for individual zone control.

• Chillers typically use water or refrigerant to cool large buildings, e.g., centrifugal chillers for commercial use.

• VRF systems use refrigerant as the cooling medium and can simulta...read more

COP measures efficiency in heating/cooling systems; heat load calculations determine required capacity for HVAC systems.

• COP (Coefficient of Performance) is the ratio of useful heating or cooling provided to the energy consumed.

• Heat load calculations assess the thermal energy needed to maintain desired indoor temperatures.

• Types of PCBs (Printed Circuit Boards) in VRF (Variable Refrigerant Flow) systems include control P...read more