What Is Meant by Character, Field, Record, and File? Data is classified in a hierarchy, with each level of data consisting of one or more items from the lower level. A bit is the smallest unit of data a computer can process. Eight bits grouped together in a unit form a byte, and each byte represents a single character, which can be a number, letter, space, punctuation mark, or other symbol. A field is a combination of one or more related characters or bytes and is the smallest unit of data a user accesses. A record is a group of related fields. A data file is a collection of related records stored on a storage medium such as a hard disk or optical disc.