Table 11-4 Determining Scsi Bus Length - Sun Microsystems Netra T4 AC100 Service And System Reference Manual

2. Determine the total SCSI bus length.
TABLE 11-4
SCSI Implementation
SCSI-2, Fast
SCSI-2, Fast/Wide
SCSI-3 Parallel Interface, Fast-20 Wide
(UltraSCSI) (WideUltra)
SCSI-3 Parallel Interface, Fast-20 Wide
(UltraSCSI) (WideUltra)
1. The maximum number of single-ended/differential SCSI devices is 16.
3. Verify the cable type used to connect external SCSI devices. You must use Fast-20
SCSI cable(s).
Ensure that the total SCSI cable length does not exceed the permissible total SCSI
bus length.
11.3.2.2 SCSI-2 (Fast Wide SCSI) External Devices
If you connect SCSI-2 (Fast Wide SCSI, 20Mb data transfer rate) external devices to a
Netra t 1400/1405 system, follow these cabling and configuration guidelines (as
shown in
If all external mass storage devices use 68-pin connectors, connect all non-Sun
devices to the Netra T4 system first and follow them with Sun devices. Sun
devices use auto-termination.
If external mass storage devices consist of 68-pin Sun devices and 50-pin devices,
connect the Sun 68-pin devices to the Netra T4 system first and terminate the
daisy chain with the 50-pin device and its terminator.
The total SCSI bus length for all external SCSI devices is 6.0m (19.7ft), including
the internal cabling.
Determining SCSI Bus Length
) to ensure proper device addressing and operation:
FIGURE 11-5
Data Transfer
Bus Width Rate, Mb/s
8 bits 10
16 bits 20
16 bits 40
16 bits 40
Chapter 11 External I/O Connectors
Number of SCSI
Devices Bus Length
1–8 6.0 m
1–8 6.0 m
1–4 3.0 m
1
5–8 1.5 m
11-7