The storage capacity of the internal hard disk drive in the 12.1-inch models is 15 or 20 GB. The internal hard disk in the 14.1-inch model has a capacity of 20 GB. A 30-GB drive is available as an option. The drive uses the Ultra DMA IDE (integrated drive electronics) interface, also called DMA/33 and ATA-4.
The software that supports the internal hard disk is similar to that in previous models with internal IDE drives and includes DMA support. For the information about that software, see the references in "ATA Devices".