Microsoft® SQL Server 2008 R2 Unleashed

Repeatable Read Isolation

In Repeatable Read mode, SQL Server provides the same level of isolation for updates as in Read Committed mode, but it also allows the data to be read many times within the same transaction and guarantees that the same values will be read each time. Repeatable Read isolation mode prevents other users from updating data that has been read within the transaction until the transaction in which it was read is committed or rolled back. This way, the reading transaction does not pick up changes to the rows it read previously within the transaction. However, this isolation mode does not prevent additional rows (that is, phantom reads) from appearing in the subsequent reads.

Although preventing nonrepeatable reads is desirable ...