How do database vendors implement transactions?

Question

When working with database it is often essential to use transactions. Say for example that I want to transfer a certain amount of money from account A to account B. This inv

Answer 1

The ACID - Implementations page on wikipedia will get you started on write-ahead logging, shadow paging and multi-version concurrency control. Follow the links to find more.

Each DBMS vendor implements their own algorithms, often several different ones depending on the context, full ACID or relaxed requirements, distributed transaction consistency requirements etc...