Distinguish between spanned and unspanned records with a neat diagram.

When an attribute is empty in a variable-length record, the null bitmap is utilised. It is possible for a tuple to have all or almost all of its properties set to null under unusual circumstances. If records are represented differently, the extra space used up by a null attribute might be reduced to a single bit.

What exactly is meant by the term "file handling," and why are its services required in the first place? Please include as much detail as you can regarding.