Question

Calculate and specify how much memory is needed to store price values of 24 items.

Answer 1

Grouping Bits - We need to convert all memory requirements into bits (b) or bytes (B). It is therefore important to

understand the relationship between the two.

A bit is the smallest unit of memory, and is basically a switch. It can be in one of two states, "0" or "1". These states

are sometimes referenced as "off and on", or "no and yes"; but these are simply alternate designations for the same

concept. Given that each bit is capable of holding two possible values, the number of possible different combinations

of values that can be stored in n bits is 2n

. For example:

1 bit can hold 2 = 21

possible values (0 or 1)

2 bits can hold 2 × 2 = 22

= 4 possible values (00, 01, 10, or 11)

3 bits can hold 2 × 2× 2 = 23

= 8 possible values (000, 001, 010, 011, 100, 101, 110, or 111)

4 bits can hold 2 × 2 × 2 × 2 = 24 =16 possible values

5 bits can hold 2 × 2 × 2 × 2 × 2 = 25 =32 possible values

6 bits can hold 2 × 2 × 2 × 2 × 2 × 2 = 26

= 64 possible values

7 bits can hold 2 × 2 × 2 × 2 × 2 × 2 × 2 = 27

= 128 possible values

8 bits can hold 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 = 28

= 256 possible values

M

n bits can hold 2n

possible values

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