Binary Large Object

A blob (alternately known as a binary large object, basic large object, BLOB, or BLOb) is a collection of binary data stored as a single entity in a database management system. Blobs are typically images, audio or other multimedia objects, though sometimes binary executable code is stored as a blob. Database support for blobs is not universal.

Blobs were originally just amorphous chunks of data invented by Jim Starkey at DEC, who describes them as "the thing that ate Cincinnati, Cleveland, or whatever". Later, Terry McKiever, a marketing person for Apollo, felt that it needed to be an acronym and invented the backronym Basic Large Object. Then Informix invented an alternative backronym, Binary Large Object.

"Blob" was originally used as a term for moving large amounts of data from one database to another without filters or error correction. This sped up the process of moving data by putting the responsibility for error checking and filtering on the new host for the data. The act of moving huge amounts of data was called "blobbing", as in the sentence, "Just blob that data over." This came about by the image of somebody grabbing fistfuls of material from one container and putting it in another without regard to what was in the "blob" they were grasping.

The data type and definition was introduced to describe data not originally defined in traditional computer database systems, particularly because it was too large to store practically at the time the field of database systems was first being defined in the 1970s and 1980s. The data type became practical when disk space became cheap. This definition gained popularity with IBM's DB2.