ATA (IDE) - Supports PIO modes 0,1 & 2, SingleWord DMA modes 0, 1 & 2, MultiWord DMA mode 0. Running at a maximum of 8.3MBps. ATA-2 (Enhanced IDE or Fast ATA) - Support for PIO modes 3 & 4, MultiWord DMA modes 1 & 2. Also supports LBA (Logical Block Addressing and block transfers). Running at a maximum of 16.6MBps. ATA-3 (Ultra-ATA, Ultra DMA, ATA33, DMA33) - Supports Ultra DMA mode 2 running at 33MBps. Adds improved reliability and drive security. ATA-4 (ATA66, Ultra DMA66, DMA66) - Supports DMA mode 4. Running at a maximum of 66MBps. (Requires 80 wire cable to achieve 66MBps) ATA-5 (ATA100, Ultra DMA100, DMA100) - Supports DMA mode 5. Runs at a maximum of 100MBps. ATA-6 (ATA133, Ultra DMA133, DMA133) - Supports DMA mode 6. Runs at a maximum of 133MBps. Adds support for drives larger than 137GB. **** All ATA standards are 16-bit, however current BIOS's implement a feature that links two 16-bit transfers together so half the 32-bit PCI bus isn't wasted. Although they get very confused and misinterpreted (as seen above), ATA is a drive interface standard. IDE (Integrated Drive Electronics) and EIDE (Enhanced IDE) are drive design or configuration standards. DMA (Direct Memory Access) and UDMA (Ultra DMA) are access methods for the drive(s), which allow transfer(s) to occur between the drive and RAM while bypassing the CPU (the data is 'controlled' by the hard drive controller and data is passed along a DMA Channel). ATAPI (AT Attachment Packet Interface) is an extension of ATA-2 (EIDE) that allows the interface to support CDROMs and tape drives. [ Close ]