Digital Equipment PRIORIS ZX 5000 MP, User Manual, Page: 84 / 169

Expanding Your Server
3-39
Adding Mass Storage Devices
Your server has three drive bay areas. Mass storage devices such as
SCSI hard disk drives, floppy diskette drives, SCSI CD-ROM drives, and
SCSI tape backup systems are installed in these drive bay areas. The
three drive bay areas are:
•
Left-front access drive bay area—This area has one 5¼-inch SCSI
CD-ROM drive and one 3½-inch diskette drive (standard on all Prioris
ZX 5000 MP Series Servers).
•
Top-right front access drive bay area—This area has room for two
wide
(68-pin) or narrow (50-pin) 5¼-inch or 3½-inch half-height SCSI de-
vices or one full-height, 5¼-inch device .
•
Lower-right front access drive bay area—This area has room for
seven
3½-inch, wide or narrow Fast SCSI-2, hot-swap devices.
Onboard SCSI Controllers
The main logic board includes two Adaptec

AIC-7870 wide/fast SCSI-2
controller chips

channels A and B

integrated as PCI bus masters.
These controllers support data path widths of 8-bit (narrow SCSI) at a data
transfer rate of 10 MB/sec and 16-bit (wide SCSI) at a data transfer rate of
20 MB/sec. As PCI bus masters, these controllers support data transfer
rates of 133 MB/sec.
You can connect up to seven 8-bit narrow SCSI devices or up to fifteen 8-
bit fast and/or 16-bit wide SCSI devices (as long as no more than seven 8-
bit fast devices are used), with one controller to each channel. For exam-
ple, tape drives, printers, optical media drives, and other devices.
The SCSI controller provides active negation outputs, controls for external
differential transceivers, a disk activity output, and a SCSI terminator
power-down control.