MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -memory data register (MDR)-holds the contents found at the address held in the MAR, or data which is to be transferred to main memory. current instruction register (CIR)-holds the instruction that is currently being decoded and executed. accumulator (ACC)-holds the results of processing.

Detailed explanation-2: -Memory Buffer Register (MBR)-a two-way register that holds data fetched from memory (and ready for the CPU to process) or data waiting to be stored in memory. Current Instruction register (CIR)-a temporary holding ground for the instruction that has just been fetched from memory.

Detailed explanation-3: -The MDR is a two-way register. When data is fetched from memory and placed into the MDR, it is written to go in one direction. When there is a write instruction, the data to be written is placed into the MDR from another CPU register, which then puts the data into memory.

Detailed explanation-4: -Detailed Solution. The correct answer is Memory Buffer Register. Memory Buffer Register holds the contents of data or instruction read from, or written in memory.

Detailed explanation-5: -The register which stores the address of the next instruction is called the program counter. Usually after each instruction is executed, the program counter increases by one (hence the use of the word counter) so that it contains the address of the next instruction.