• System crash
– There is a hardware malfunction, or a bug in the
database software or the operating system, that causes
the loss of the content of volatile storage, and brings
transaction processing to a halt. The content of
nonvolatile storage remains intact, and is not corrupted.
– The assumption that hardware errors and bugs in the
software bring the system to a halt, but do not corrupt
the nonvolatile storage contents, is known as the failstop
assumption. Well-designed systems have
numerous internal checks, at the hardware and the
software level, that bring the system to a halt when
there is an error. Hence, the fail-stop assumption is a
reasonable one.