What's the difference between fat and fat32? I read about (file allocation table) but I didn't understand it. Please talk about it.

Why did they do FAT32?

FAT stands for File Allocation Table. It's basically a table of contents or index of where files are located on your hard drive.

FAT (actually FAT16) is a 16 bit file system structure that allocates 16 bits to to the cluster addresses on the HD. The clusters are where data is actually stored on the HD.

FAT32 improves upon this by doubling the number of bits available for addressing. This means you can physically access more space on the hard drive and it means the cluster size is smaller.

The smaller the cluster size, the less wasted space on the HD. For example, a cluster size of 512 bytes means that anything bigger than 512 bytes will have to occupy two clusters. Even if it's 514 bytes, you still have to use 2 clusters. That means the other 510 bytes of the second cluster are unused, and unusable because the cluster is marked as unavailable. Smaller clusters therefore mean that space is better allocated and not wasted.

More information can be found at Wikipedia.