Computer Organization and Architecture - General Questions

A cache has a hit time of 2 ns, a miss penalty of 50 ns and a hit ratio of 0.9. The average memory access time is:

DMA (direct memory access) allows:

Using Amdahl's law, if 80% of a program is sped up 4 times, the overall speed-up is:

Cache hit ratio is:

A control hazard in a pipeline is caused by: