Scsi Bus Differences - HP Visualize J5000 Supplementary Manual

SCSI Bus Differences

A SCSI (Small Computer Systems Interface) bus is an IEEE standard bus for connecting a
workstation to internal and external SCSI devices running at different speeds. There may
be one device connected to the external SCSI port, or several SCSI devices may be
daisy-chained together and connected to the external SCSI port. Examples of these SCSI
devices are 4 mm DDS-format tape drives, CD ROM drives, and hard disk drives.
There are two types of SCSI buses available with the J5xxx and J7xxx workstation: a
Narrow Single-Ended SCSI-2 bus (NSE), and an Ultra2 Wide Low Voltage Differential
SCSI bus (LVD). The following table shows the specification differences between these two
SCSI buses.
CAUTION Do not connect NSE SCSI devices to the LVD SCSI connector, or vice versa,
because damage may occur. Currently Hewlett-Packard does not support
mixing NSE and LVD devices on the same SCSI bus.
Table C-1. SCSI Bus Differences
SCSI Type Transfer Rate
NSE Up to 20 MB/sec
LVD Up to 80 MB/sec
1
Address 7 is reserved for host controller use on all buses.
2
This information is specific to the HP V
Appendix C
Data Bus Maximum
Width
Addresses
8 bits 0 through 6
16 bits 0 through 6;
8 through 15
J5xxx and J7xxx workstations.
ISUALIZE
SCSI Bus Differences
Maximum
Cable Physical
1 Length
Location
3.0 meters Internal and
(9.84 feet) external
12 meters Internal and
(39.37 feet) external
SCSI Connections
Device
2
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