What are a bit, Nibble and Byte?
Computer memory is an electronic chip which consists of millions of transistors and capacitors. A transistor and a capacitor are paired to create a memory cell that stores one bit of data. Such 4 bits form a Nibble and 8 bits form a Byte.
Many modern computers are byte-addressable which means for each byte we have a unique address and the data can be fetched only in the multiples of bytes.
For example, if you want to read 4 bits of info, then you need to read the entire 1 Byte of data and perform shifting operations to get the required 4 bits of data.
How addressing is done?
A 32-bit computer has only 232 address spaces where each byte is given a unique address. It means it can support only 4GB (i.e. 232 bytes) of memory. Even if you insert 16 GB of RAM in a 32-bit machine it uses only 4GB.
Following is how the addressing looks like
For our convivence, instead of binary, we represent addresses in Hexa decimal format. Each Hexa decimal digit represents 4 bits of data. So, with a single hex digit, we can easily remember 4 bits of info.
For example, the following 32-bit binary data can be easily written as 'F855ABD5'
Please have a look at the following articles for more information on the Hexa decimal representation.