HP LH4r HP Netserver LH 3/3r User Guide - Page 37

Chapter 6 Installing Mass Storage Devices Hot-Swap Mass Storage Cage Low-Profile and Half-Height Drives SCSI hot-swap hard disk drives come in two heights: the 1-inch low-profile drive and the 1.6-inch half-height drive. Ultra2 drives are LVD (low voltage differential) drives, which allow the integration of the differential drivers and receivers into SCSI drive controllers. Ultra2 technology provides increased signal quality, and ensures the same data integrity as the previous high voltage differential designs at a reduced cost. An added benefit of the low voltage design is that the SCSI bus cable can extend up to 12 meters. CAUTION Do not mix devices with high voltage differential (HVD) drivers and receivers and devices with SE, Ultra2 or multimode drivers and receivers on the same SCSI bus. I/O circuits used by devices with SE, Ultra2 or multimode drivers and receivers do not operate at HVD levels and should never be exposed to HVD environments. If you mix SCSI SE and SCSI Ultra2 devices, system performance will be adversely affected. For best performance, use only Ultra2 devices. Filler Panels When you have fewer drives than the hot-swap mass storage cage supports, a 1-inch filler panel must be inserted in each empty disk location. Filler panels ensure that drive cage has the proper ventilation and air flow. Remove the filler panel when you insert a new drive. CAUTION The filler panels serve an important purpose by helping the internal components ventilate and preventing excessive electromagnetic radiation. If these fillers are left out of the drive shelves, thermal damage and/or excessive EMI could occur. Drive Spacers When your drive cage holds a mix of 1-inch and 1.6-inch drives, you may need to add 0.5-inch drive spacers. The drive spacer fills the gap between adjacent drives 29