Which of the following memories has the shortest access time?
- A.Cache Memory
- B.Magnetic Bubble Memory
- C.Magnetic Core Memory
- D.Random Access Memory
Show answer
Correct answer: A. Cache Memory
Explanation
The correct answer is A, Cache Memory. Cache is a small quantity of very fast static RAM placed between the processor and main memory to hold the instructions and data most likely to be needed next, and of the options given it has the shortest access time; only the registers inside the processor itself are faster. Cache is graded as L1, L2 and L3, with L1 nearest the core and quickest. D is wrong because random access memory is the main memory and is slower than cache, which is the whole reason cache exists. B is wrong because magnetic bubble memory is an old non-volatile technology that stored data as tiny magnetised regions in a thin film and was far slower than semiconductor memory. C is wrong because magnetic core memory, built from tiny ferrite rings, was the main memory of second generation computers and had access times measured in microseconds rather than nanoseconds.