Information storage and retrieval (ISR) is a concept associated with large quantities of information stored in relatively sizable (and therefore, costly) computers and which requires relatively extensive software to accommodate the whole process. Generally, the connection between software and hardware is extremely strong; i.e., a particular Information Storage and Retrieval package can only be used on the computer for which it was written. This is the case, for example, with IBM's ‘Stairs’, Siemens’ ‘Golem’ and Univac's ‘Unidas’ package.