Overview: JMicron/JMB391 JMB391 RAID Port Multiplier Chip
1. Overview JMicron JMB391 is a single chip, 1 to 5-ports Serial ATA II Port Multiplier with RAID function support. It is designed to provide SATA port expansion, data protection and performance aggregation at various applications. JMB391 uses JMicron’s production-proven Multi-port Serial ATA PHY technology and JMicron-proprietary storage processor to provide very high efficient SATA RAID operation. With an easy configuration scheme, the device can be a pure port multiplier which provides SATA port expansion just like a SATA Hub, or hard-drive performance booster which provides a high performance device seen by host controller or hard-drive data protector which automatically backup data to prevent data loss from hard-drive damage. JMB391 also has advance mode to provide both benefit of performance boost and data protection. JMB391 is a self-contained storage processor chip which pletely frees up the main CPU loading and the SATA ports ply with eSATA specification, making it suitable for use in both internal system and external storage applications 2.
