Skip to content
GK24
Prime
Computer AwarenessEasy

Which of the following is the fastest memory in a computer system?

  1. A.Cache memory
  2. B.Register
  3. C.Main memory
  4. D.Hard disk

Correct answer

B. Register

Explanation

The correct answer is B, register. A register is built into the CPU itself and holds the word the arithmetic and logic unit is operating on at that instant, so it is read and written in a single clock cycle. Nothing in the machine is closer to the processor, and nothing is faster.

Option A, cache memory, is the second fastest and is the right answer only when registers are missing from the options; it sits between the CPU and main memory and is built from static RAM. Option C, main memory, is the DRAM the processor addresses directly, which is fast but an order slower than cache because every cell has to be refreshed. Option D, the hard disk, is secondary storage with moving platters and heads, so its access time is measured in milliseconds against nanoseconds for the levels above it. The order to memorise is register, cache, main memory, secondary storage, magnetic tape.

Read the full article: Memory and Storage: RAM, ROM, Cache and Units

Practice Questions

View all
Q1.Computer AwarenessEasy

How many bits make one nibble?

  1. A.2 bits
  2. B.4 bits
  3. C.8 bits
  4. D.16 bits
Show answer
Correct answer: B. 4 bits

A nibble is half a byte, that is four binary digits, and it matters because one nibble is written as exactly one hexadecimal digit, from 0 to F. That is why memory addresses in hexadecimal are read four bits at a time.

Q3.Computer AwarenessMedium

The contents of an EPROM chip are erased by exposing it to

  1. A.An electrical signal
  2. B.Ultraviolet light
  3. C.A magnetic field
  4. D.Infrared radiation
Show answer
Correct answer: B. Ultraviolet light

An Erasable Programmable Read Only Memory chip carries a small quartz window over the silicon; ultraviolet light shone through that window releases the trapped charge from every cell at once and returns the chip to its blank state, after which it can be programmed again.