# Digital Storage

• In modern technology most information is stored and transferred in binary form. This means that the information is coded by a group of 0s and 1s (alternatively other symbols can represent the 0 or one). In A level Physics it is a key point to understand this storage.
• Usually information is grouped in 8 binary digits, bits, these 8 bits are called 1 byte. To explain how this works an example is necessary.
• To code 20 in 1 byte, the byte would read 0010100, the right most digit represents 2^0 the next along represents 2^1 and so on. Therefore this binary digit 0010100 is 2^2+2^4 (^means to the power of) which adds to 20. With a bit of practice you should be able to remember this easily.
• This principle does follow from the logarithms in the earlier topic, each next digit gives increases the number of combinations (alternatives) in the same way as a logarithmic scale. One byte has 256 2^8 alternatives.
• There are also other forms of encoding, mainly octal and hexadecimal octal of base 8 and hexadecimal of base 16, now these follow a very similar method of coding as the binary shown about. But the numbers of symbols are different, that is for octal there are 8 symbols from 0-7 and in hexadecimal there are 16. So for the coding 3A in hexadecimal (A stands for 10 B for 11 and so on till 15) the answer in our decimal system of our language would be 3*16^1+10*16^0. In the same way as before we multiply the symbol by the base to the power of the position the base is away from the left hand side.