Scsi Bus Length Constraints; Se Scsi Bus Length; Lvd Scsi Bus Length - HP j6700 - Workstation Service Handbook

SCSI Connections

SCSI Bus Length Constraints

SCSI Bus Length Constraints
This section discusses SCSI bus lengths constraints for the SE and LVD SCSI buses.

SE SCSI Bus Length

The maximum cable length for an SE SCSI bus is 3 meters. The J6700 workstation use a
negligible amount of this maximum cable length.
NOTE When calculating the total SE SCSI cable/bus/trace length used externally,
remember to account for cables connecting external devices together as well
as the bus length internal to those devices.
There are two total cable length specifications you need to consider when dealing with an
SE SCSI bus on a workstation. Note that these specifications are based on the requirement
that the SCSI device being connected to the SE SCSI bus does not exceed the maximum
capacitance of 25 picofarads (pF). Please check with the vendor of the SCSI device if you
are not sure of the device's maximum capacitance.
The total cable length specifications are as follows:
• For a total of one to four devices being connected to the SE SCSI bus, the total length of
cable used should not exceed 3.0 meters.
• For a total of five to eight devices being connected to the SE SCSI bus, the total length
of cable used should not exceed 1.5 meters.
NOTE The computer is counted as one of the devices, and the internal length of its
cabling is 0.15 meters. This length needs to be considered in determining the
total cable length.

LVD SCSI Bus Length

The maximum cable length for an LVD SCSI bus is 12 meters. The J6700 workstation use
1 meter of this maximum cable length internally. This means that up to 11 meters of cable
can be used for connecting external LVD SCSI devices to this workstation.
NOTE When calculating the total LVD SCSI cable/bus/trace length used externally,
remember to account for cables connecting external devices together as well
as the bus length internal to those devices.
146 Appendix B