ThinkVantage key, or F11 Key.

Rescue and Recovery version 3.0 consists of a bootable partition containing various system recovery tools, including full recovery of the preinstalled Windows XP partition. It can be activated by pressing the "ThinkPad", "Access IBM" or "ThinkVantage" Button during system boot. It contains a FAT filesystem (sometimes labeled "IBM_SERVICE", "SERVICEV001", etc.), and has partition type 0x12 ("Compaq diagnostics" in fdisk).

As opposed to a Hidden Protected Area Recovery partitions are ordinary partitions, accessible through the partition table. As they are ordinary partitions they are accessible by ordinary partitioning tools. They should be dealt with carefully.

Rescue and Recovery is a Windows-specific feature. If you intend to recover into Windows when you have an issue, it is important to follow the warnings here carefully. If you intend to run another operating system exclusively and never return to Windows, removing this partition is safe. If you remove it, you can still reinstall windows at a later time, provided you have created a Recovery set of discs (1CD + 1DVD or 5CDs required). Booting from the Recovery CD will restore the system to the factory state including the recovery partition.

Or:

http://www-307.ibm.com/pc/support/site.wss/MIGR-46088.html