SCSI Connections

SCSI Bus Differences

SCSI Bus Differences

A Small Computer Systems Interface (SCSI) bus is an IEEE standard bus for connecting your workstation to internal and external devices (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 and hard disk drives.

There are two types of SCSI buses available with this workstation—an Ultra Narrow Single-Ended SCSI bus (NSE SCSI), and an Ultra2 Wide Low-Voltage Differential SCSI bus (LVD SCSI). The following table shows the specification differences between these SCSI buses.

CAUTIONCurrently Hewlett-Packard does not support mixing Ultra Narrow Single-Ended and Ultra2 Wide Low-Voltage Differential devices on any one bus type.

Table 4-1

SCSI Bus Differences

 

 

 

 

 

 

 

 

 

 

 

Type

Data

Data Bus

Available

Maximum

Device

 

 

Transfer

Width

SCSI

Cable Length

Physical

 

 

Rate

 

Addresses1

 

Location2

 

 

 

 

 

 

 

 

Ultra Narrow

Up to 20

8 bits

0 through 6

3.0 meters

External

 

Single-Ended

Mbytes/sec

 

 

(9.84 feet)

 

 

 

 

 

 

 

 

 

Ultra2 Wide

Up to 80

16 bits

0 through 6; 8

12 meters

Internal and

 

Low-Voltage

Mbytes/sec

 

through 15

(39.37 feet)

external

 

Differential

 

 

 

 

 

 

 

 

 

 

 

 

1.Address 7 is reserved for host controller use on all buses.

2.This information is specific to the HP V ISUALIZE B Class and C Class computer.

Chapter 4

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