Indirect methods [of access] may be classified 1) as sequential, in which there is some type of search through a sequence of records (but generally not a complete search that starts from the first record and proceeds through the whole file), or 2) as nons

Indirect methods [of access] may be classified 1) as sequential, in which there is some type of search through a sequence of records (but generally not a complete search that starts from the first record and proceeds through the whole file), or 2) as nonsequential, in which the desired record is located without such a search. A common nonsequential method is based on the use of an index and is usually called 'Index Sequential Access Method' (ISAM). Other nonsequential access methods use key transformations and are usually referred to as 'randomizing' or 'hashing' techniques.