Building on Quicksand

Understand

Reliable systems have always been built out of unreliable components.

• Early on, the reliable components were small such as mirrored disks or ECC (Error Correcting Codes) in core memory.
• These systems were designed such that failures of these small components were transparent to the application.
• Later, the size of the unreliable components grew larger and semantic challenges crept into the application when failures occurred.