Question

At the time of a system crash, only the log entries that have been written back to ___ are considered in the recovery process because the contents of main memory may be lost.

1) secondary storage
2) cache memory
3) main memory
4) registers

Answer 1

1. Final answer:

In the event of a system crash, recovery is reliant on log entries in secondary storage because it is non-volatile and doesn't lose data, unlike main memory, cache, and registers, which are volatile.

Step-by-step explanation:

During a system crash, the recovery process considers only the log entries that have been written back to secondary storage. This is because secondary storage, such as hard drives, SSDs, or any non-volatile memory, is designed to retain data even when the system is powered down or encounters a critical failure. The contents of main memory, such as RAM, along with cache memory and registers, are volatile and can be lost when a crash occurs.

Secondary storage is therefore crucial for maintaining the integrity of persistent data and provides a baseline for recovery operations by keeping a record of transactions in the form of logs. These logs are used to restore the system to a consistent state by redoing completed transactions and undoing incomplete ones, a process known as transaction logging.