Computer System Architecture Questions and Answers

Answer: D

Correct answer: 2

Execution time is the number of CPU clock cycles divided by the clock rate:

\[ \text{Execution time}=\frac{\text{CPU clock cycles}}{\text{Clock rate}}=\frac{4}{2}=2 \]

Answer: C

Correct answer: Memory Space

The set of addresses that physically exist in main memory is the memory space; the set of addresses a program may generate is the address space. Keeping the two apart is the basis of virtual memory, where the address space is larger than the memory space.

Answer: C

Correct answer: Interrupt driven I/O

With interrupt-driven I/O the processor issues the transfer and then continues with other work; the device raises an interrupt when it is ready, so the CPU never sits polling. Programmed I/O ties the processor up in a wait loop, and DMA removes the processor from the transfer altogether rather than letting it run a program concurrently with it.

Answer: D

Correct answer: Pulse generator

A digital system is timed by a train of clock pulses produced by a pulse generator; the clock is the signal, not the source. A decoder or a counter distributes or divides that signal but does not create it.

Answer: A

Correct answer: In Accumulator

The accumulator is the register that holds one operand of an arithmetic or logic operation and receives the result. Cache and ROM are memory rather than working registers, and the instruction register holds the instruction being executed, not its result.

Answer: B

Correct answer: tightly coupled system

A multiprocessor system has two or more processors sharing the same memory, bus and clock under a single operating system. Processors that share memory in this way are described as tightly coupled. A loosely coupled system is one whose machines have their own memory and communicate over a network - that is a distributed or clustered system, not a multiprocessor.

Answer: B

Correct answer: parallel clusters

Parallel clusters allow more than one host to access the same data on shared storage at the same time, which needs a special distributed file system to arbitrate the accesses. A Beowulf cluster is a commodity-hardware compute cluster and is not defined by shared data access.

Answer: A

Correct answer: Replacing processor with faster version

Throughput is work completed per unit time, so it rises when the machine gets through each task faster or can run more tasks at once. A faster processor does the first directly. Changing the operating system, the cache or the I/O may help in particular cases, but the processor is the general answer the definition points to.

Answer: C

Correct answer: DMA

Direct Memory Access lets an I/O device transfer a block of data straight to or from memory without the CPU handling each word, which is why it is the standard high-speed transfer technique. CAD and CAM are application areas, not transfer methods.

Answer: D

Correct answer: Handshaking

In handshaking each unit sends a control signal to acknowledge the other - a request from the sender and a reply from the receiver - so neither has to assume the other is ready. A strobe uses a single pulse and gets no acknowledgement in return, which is the distinction being tested.