Glass house is a term for centralized computing in an enterprise and the mindset of those who plan and administer it. The term originated from the glass windows that, beginning in the 1950s, corporations began to build into their large central computer rooms to let visitors peer in on their impressive rows of mainframe computers, direct access storage devices and tape racks, and other hardware. These large rooms were built with an elevated floor that could accommodate, underneath the floorboards, telecommunications and local channel cabling as well as water pipes for cooling the larger water-cooled mainframes. As hardware technology and physical footprints have changed, the physical glass house has changed or even disappeared into smaller spaces and closets. However, much computing in an enterprise remains (and is expected to remain) centrally administered and, to the extent that it does, the glass house point-of-view remains in fashion.