ThinkPad X3 UltraBase
The UltraBay Plus slot in this dock is a full featured one and supports hot swapping with all UltraBay Plus and UltraBay 2000 drives. You can also feed it with the UltraBay Plus battery pack to extend the overall battery life time.
This can be problematic under Debian, as the default kernel (2.6.18) do not support the IBM docks by default, as the IBM_DOCK and DOCK methods are not compatible. This is not a problem with 2.6.22 for some reason. Under 2.6.18, you need to recompile the Linux kernel with CONFIG_ACPI_IBM_DOCK enabled, and CONFIG_ACPI_DOCK disabled. You also need to hook a few scripts into the acpi events system.
#!/bin/sh # acknowledge docking with the dockstation echo dock > /proc/acpi/ibm/dock
#!/bin/sh # prepare the laptop for undocking with the dockstation echo undock > /proc/acpi/ibm/dock
event=ibm/dock GDCK 00000000 00000003 action=/etc/acpi/ibm-dock.sh
event=ibm/dock GDCK 00000003 00000001 action=/etc/acpi/ibm-undock.sh
2.6.22-rc2 actually works without a flaw, without the above modifications, provided that the "bay" and "dock" modules are loaded at boot time.