Over the course of time, a number of different form factors have been used for the Ultrabay. They are generally not cross-compatible, but there are some exceptions to that (see below for more details). Current ThinkPads no longer use the Ultrabay, due to severe space constraints. Only a few models do feature the Ultrabay nowadays, but they are unfortunately crippled in such a way that they no longer support Ultrabay batteries and hot-swapping.
Keep in mind that not all Ultrabays are made equal, as some lack an eject mechanism or pins that are needed to charge and discharge an Ultrabay battery. Some Ultrabays might also not support hot and/or warm swapping, even if they are capable of doing so in a different model (e.g. a high-end model supports hot, warm, and cold swapping, but the other lower-end model supports only cold swapping despite having the same Ultrabay type). These crippled Ultrabay variants are generally found on the low-end models, although they can also be rarely found on high-end models.
The pinout switching is performed by the BIOS and embedded controller, so that it is completely transparent to the operating system.
- Floppy drives are supported by the standard floppy driver.
- ZIP drive support is possible through the ide-disk driver.
- IDE hard disks and optical drives are supported by the ata_piix or older ide-disk driver in the linux kernel.
- Batteries are automatically handled by the hardware, but can be controlled further by using tp_smapi.
- Ultrabay Plus devices should be handled by the USB subsystem, but if the actual devices are is not known.
The Ultrabay 2000 was the first Ultrabay type to include crippled variants. Cold-swap-only (with no Ultrabay battery support) Ultrabay 2000 bays were notably installed in the A21e and the A22e, both models being MT 2655. This is not to be confused with the MT 2628 A21e, as it has a fully-featured Ultrabay 2000 bay. Eject mechanisms were still available on these crippled variants.
Cold-swap-only Ultrabay Plus bays were installed in the R30, R31, and the R32. The only redeeming fact about these crippled bays, is that the R32 had the ability to support Ultrabay batteries (as it has the pins needed to interface with one). All of them still featured eject mechanisms.
Cold-swap-only Ultrabay Enhanced bays (with no Ultrabay battery support) were installed in the R50e, R51e, R60e, R61i (some), R61e, G41, and the G50. With the exception of the R50e and the R51e, all of Ultrabay Enhanced implementations in the other models had no eject mechanisms.
Cold-swap-only Serial Ultrabay Slim bays (with no Ultrabay battery support) were installed in the P70, P71, W541, W540, T440p, T540p, L440, L540, L560, and the L570. All implementations of this specific Ultrabay type in said models did not have an eject mechanism.
Cold-swap-only Serial Ultrabay Enhanced bays (with no Ultrabay battery support) were installed in the L410, L412, L420, L421, L430, L510, L512, L520, and the L530. All implementations of this specific Ultrabay type in said models did not have an eject mechanism.
Fully featured Ultrabay types, but lacking Ultrabay battery support were installed in the W510, W520, W530, W700, W700ds, W701, W701ds, T410, T410i, T420, T420i, T430, T430i, T510, T510i, T520, T520i, T530, and the T530i. Some of these models could still utilize a second battery via the docking connector, but not all of them could or even had the functionality to do that.