The Promise SATA300 TX2plus 2+1 SATA/PATA PCI adapter offers the premier solution for combining the latest, high-performance SATA 3.0 Gb/s Serial ATA disk drives with existing Parallel (Ultra) ATA drives using the same controller. With the SATA300 TX2plus, users can connect up to two SATA drives and 2 PATA drives, offering users a cost-effective solution for upgrading their existing storage system with SATA 3Gb/s drives. While storage system performance is affected by components throughout the storage system, SATA drives with 3Gb/s can deliver significantly faster burst data throughput. Like a faster data cache, the faster burst rate when using the latest 3Gb/s drives should provide a snappier feel when opening small files and conducting the day-to-day tasks that many desktop and workstation PCs are required to perform. The controller supports Serial ATA 3Gb/s drives and conforms to Serial ATA II, Extensions to Serial ATA 1.0a specification - including Native Command Queuing and Disk Activity LED headers support. In addition to NCQ, the controller also supports Tagged Command Queuing with drives that can take advantage of this capability. Command Queuing increases I/O performance by intelligently reordering data requests so that the data can be more quickly accessed than if the commands weren't ordered. For support of legacy parallel ATA devices, the SATA300 TX2plus supports Ultra/ATA devices up to 133MB/sec data transfer rate. Drawing upon Promise's expertise in ATA, the controller incorporates performance-enhancing features such as CRC error checking and separate timing for two devices attached to one ATA channel. The SATA300 TX2plus also supports parallel ATAPI devices. The low-profile form factor SATA300 TX2plus PCI adapter incorporates many of Promise Technology's advanced host bus adapter features. The 66MHz PCI bus supports up to 266MB/sec burst data transfer rate. The SATA300 TX2plus also includes large LBA support for drives above 137GB, and its onboard BIOS automatically identifies and configures drive type (Serial ATA, Ultra DMA mode). The controller supports up to two controllers in the same system.