HP LH4r Ultra3 SCSI Hot-Swap Hard Disk Drive and Tray User Guide - Page 5

1 Introduction to Ultra3 Drives Overview Ultra3 SCSI hot-swap hard disk drives provide higher I/O bandwidth and can work with longer cable lengths than Ultra drives. Ultra3 drives operate at SCSI bus data rates of up to 160 MB per second--double the rate of Ultra2 SCSI. With Ultra3 drives, HP NetRAID environments and applications will show immediate increases in performance. Note: These drives are also backward compatible with Ultra2 controller systems. Ultra3 Drives are Low Voltage Devices Ultra3 drives have LVD (low voltage differential) signal levels. The low voltage requirements allow the integration of the differential drivers and receivers into drive SCSI controllers. LVD provides the signal quality necessary to run at Ultra3 data rates. LVD also allows for significantly longer SCSI bus cable lengths. Ultra3 Drives Have Two Heights; Drive Cages Have Several Sizes Ultra3 disk drive modules come in two heights: the 1-inch (2.5 cm) low profile drive and the 1.6-inch (4 cm) half-height drive. NetServer drive cages come in several sizes. There are two types of six-drive cages. The LH3, LH4, and RS-12 cages support a mix-and-match of 1-inch low profile drives and 1.6-inch (4 cm) half-height drives. Other NetServers with six-drive cages support either 1-inch (2.5 cm) low profile drives or 1.6-inch (4 cm) half-height drives. Refer to your NetServer manuals for details. Chapter 3 lists the places where the supported configurations can be found. Filler Panels When you have fewer drives than the hot-swap cage supports, filler panels must be inserted in empty disk locations. Filler panels ensure that the hot-swap cage has the proper ventilation and air flow. You will remove the filler panel when you insert a new Ultra3 disk drive module. (Figure 2-1 in the next chapter shows a filler panel.) 1