Adaptec AHA-3950U2B Dual Address Cycle (DAC) provides greater system memory addressability. Target mode for supporting clustering,bridge and RAID applications. Multitasking operating system support (through scatter/gather, disconnect/reconnect, tagged command queuing support). Advanced multimode Ultra2 SCSI I/O cell for supporting Ultra2 (LVD) or single-ended (SE) devices. Support for 255 simultaneous active SCSI commands per channel. JTAG boundary scan to support system level interconnect testing. 3.3V / 5V PCI interface for providing flexibility for designing high-performance, low-power systems. Enhanced Logical Unit Number (LUN) supports up to a maximum of 32 LUNs. I2O-ready system compatible. PCI Hot-Plug compatible.