Quiz Review 3: Transactions and System R (Updated May 22 11pm)
Transactions
Atomicity
All at once
In the face of interruption and failure
Locking, which may lead to inefficiency and or deadlock
Recoverability
Shadowfiles
Logging
Checkpoints
System R
Shadow files are also used to help with recoverability. They
ensure that particular file updates can be made atomically.
Uses a log to support undo/redo operations. This is used to ensure
that partial or aborted transactions which were SAVEd (by other
transactions) to the same file can be backed out.
System R was designed to require both shadow file and a log to
implement transactional atomicity.