Very large digital objects that are unstructured and could not be fit in databases directly are today stored by database management systems as Binary Large Objects (BLOBs) or Basic large Objects. Such kind of data could be graphical images, audio or video or even binary executable codes (or simply .exe files). Though not every database system supports this kind of data type, all major database systems like SQL, Oracle and DB2 help store such BLOBs. In fact, DB2 was the earliest to popularize this technology and allowed users to store such collection of binary data as a single entity and consume them in their systems as complete units at a time.
Originally, BLOB was not an acronym and stood for just unstructured chunks of data. Later it was given the current expansion of Basic large object or the latest and widely used expansion Binary large Object.
At the time when data came to be stored in databases, there was no means of storing this kind of large data in any particular field with a defined data type. With limited storage available at a huge cost, storing such data in databases were not even thought of and were stored as separate simple single continuous sequential files. After the storage spaces for data became cheap, databases started supporting this large data type that can contain amorphous or unstructured data.
Today, Remote BLOB store (RBS) for SQL Server lets database administrators store binary large objects (BLOBs) in commodity storage solutions instead of directly on the server. This saves a significant amount of space and avoids wasting expensive server hardware resources. RBS provides a set of API libraries that define a standardized model for applications to access BLOB data. RBS also includes maintenance tools, such as garbage collection, to help manage remote BLOB data.
Microsoft's online Infrastructure and Platform as services Windows Azure and SQL Azure store all data in the cloud in this format. Since this data in replicated multiple times in the various datacentres to provide redundancy, Multiple downloads of the same chunk of data becomes simplified and much faster because of the convenience this kind of BLOB storage offers.
Microsoft Access tables also allows storage of Blobs in a field with the OLE Object data type.