**Problem Detail:**

A typical HDD would represent information as either 1 (e.g. spin up) or 0 (e.g. spin down). Let's assume you want to represent the information physically in a hex system with 16 states, and assume this is possible with using some physical form (maybe the same spin).

What is the minimum physical size of a memory element in this new system in units of binary bits? It seems to me that the minimum is 8 bits = 1 byte. Therefore, going from a binary representation to a higher representation will, everything else equal, make the minimum variable size equal 1 byte instead of 1 bit. Is this logic correct?

###### Asked By : student1

###### Answered By : Yuval Filmus

One hexadecimal digit contains 4 binary digits. You can compute this as follows: $\log_2 16 = 4$. Alternatively, $2^4 = 16$. So the minimal memory element will contain 4 bits' worth of information.

This also works when the number of states is not a power of 2, but you have to be more flexible in your interpretation.

Question Source : http://cs.stackexchange.com/questions/52233

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