This appendix describes technical information about the Small Computer Systems Interface (SCSI) and covers the following topics:
There are two basic methods of connecting the Multi-Disk Pack or the Desktop Disk Pack to your system:
Connecting the SCSI cable of the Multi-Disk Pack or Desktop Disk Pack to the SCSI connector of your system.
Connecting the SCSI cable of the Multi-Disk Pack or Desktop Disk Pack to the SCSI connector of another SCSI device.
Use direct connection to connect the first SCSI device in the SCSI bus to the computer system.
See Figure A-1 and Figure A-2.
See Figure A-1 and Figure A-2. A regulated SCSI terminator is stamped "REGULATED." For more information, see Figure A-5 and the section "Regulated SCSI Termination."
A daisy-chain is a means of connecting a number of SCSI peripherals to a host adapter. Daisy-chaining allows a single SCSI host adapter on the system to connect to more than one SCSI peripheral. If you want more than one SCSI peripheral on a bus, you need to daisy-chain SCSI peripherals.
Caution -
Note - You cannot daisy-chain differential SCSI drives to a Multi-Disk Pack or Desktop Disk Pack. You must use a DSBE/S SBus card with a differential SCSI disk drive.
See Figure A-3 and Figure A-4.
See Figure A-3 and Figure A-4.
See Figure A-3 and Figure A-4. A regulated SCSI terminator is stamped" REGULATED." For more information, see Figure A-5 and the section "Regulated SCSI Termination."
For more information, see the section "SCSI Bus Length" which follows.
A bus is a signal route to which several parts of a computer system may be connected so that signals can pass between them.
The number of SCSI devices you can add on a SCSI bus depends on the available SCSI addresses and the length of the SCSI chain or bus. The maximum SCSI bus length is 20 feet (6 meters). See Tables A-1 and A-2. Sun SPARC systems support multiple SCSI buses.
When you attach devices to the SCSI host adapter port of a SBus card, you are connecting SCSI devices to an additional SCSI bus. The total length of an additional SCSI bus includes:
The SCSI host adapter of your computer system is the primary SCSI bus. The total length of the primary SCSI bus includes:
Note - When calculating the total SCSI bus length, do not include the internal SCSI bus length of the computer system when attaching SCSI devices to an SBus card providing a SCSI host adapter port.
A standard 32-inch (0.8 meter) SCSI cable is shipped with your Multi-Disk Pack. To connect a Multi-Disk Pack or Desktop Disk Pack directly to a SPARCserver 630 or 670 system, you need a 79-inch (2.0 meter) SCSI cable (part number 530-1836) orderable from Sun. Chapter 2, "Installation," describes the installation procedure.
To directly connect a Multi-Disk Pack or Desktop Disk Pack to a desktop SPARC system (such as the SPARCstation 2, 10, or IPX) or to daisy-chain SCSI peripherals together, use the 32-inch (0.8 meter) SCSI cable supplied with the Multi-Disk Pack or Desktop Disk Pack.
Some of the cables supplied with your Sun equipment must be specific lengths to conform with engineering and safety standards. For example, the SCSI cable supplied with your Multi-Disk Pack conforms to the SCSI bus length specification.
Table A-1 lists the internal SCSI cable length of the Multi-Disk Pack, the most popular SCSI devices which support "fast SCSI," and the cable lengths of external SCSI cables. Table A-2 lists the internal SCSI cable lengths of supported computer systems.
Use Tables A-1 and A-2 to calculate the SCSI bus length. Refer to the section "Calculating the SCSI Bus Length" for examples on calculating the SCSI bus length.
Table A-1 SCSI Cable (Bus) Lengths of SCSI Peripherals
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SCSI Peripherals and Cables SCSI Cable Length -----------------------------------------------------------------------------------
Inches Meters -----------------------------------------------------------------------------------
Internal Cable Length
SCSI Peripherals and the SBus Expansion Subsystem
Desktop Storage Pack 12 0.3
Desktop Storage Module 12 0.3
Multi-Disk Pack 39 1.0
SCSI Expansion Pedestal 67 1.7
SBus Expansion Subsystem 24 0.6
External Cable Length
SCSI Cables
SCSI Devices Connected to SPARC desktop systems 32 0.8
(Multi-Disk Pack, Desktop Storage Pack, Desktop Storage
Module, SCSI Expansion Pedestal)
SCSI Devices Directly Connected to SPARC deskside 79 2.0
systems (Multi-Disk Pack, Desktop Storage Pack, Desktop
Storage Module, SCSI Expansion Pedestal
SCSI Devices Daisy Chained to Multi-Disk Pack 32 0.8
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Table A-2 Internal Cable Lengths of Supported Computer Systems
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Computer Systems (Internal Cable Lengths) Inches Meters ---------------------------------------------------------
SPARCstation LX and SPARCclassic systems 35 0.9
SPARCstation IPC , IPX, and 2 systems 20 0.5
SPARCstation ELC system 8 0.2
SPARCserver 630 system 110 2.5
SPARCserver 670 system 98 2.8
SPARCstation 10 system 35 0.9
SPARCserver 1000 59 1.5
SSHA, SBE/S FSBE/S SBus cards 4 0.1
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This section provides examples on how to calculate the SCSI bus length when connecting the Multi-Disk Pack or Desktop Disk Pack to either an additional SCSI host adapter port on an SBus card or to the built-in SCSI port of the computer system.
If you have a Multi-Disk Pack, a Desktop Disk Pack, and a Desktop Backup Pack connected to a FSBE/S SBus card, add the following cable lengths:
This totals 4.0 meters of cable, less than the 6 meter (20 feet) maximum for each SCSI bus.
If you have a a Multi-Disk Pack, a Desktop Disk Pack, and a Desktop Storage Module tape unit connected to a FSBE/S SBus card, add the following cable lengths:
This totals 4.0 meters of cable, less than the 6 meter (20 feet) maximum for each SCSI bus.
Note - Unless you are connecting the Multi-Disk Pack to a diskless system, you must be running the Solaris 2.1 operating system (SunOS 5.1) or a later release of the operating system in order to connect the Multi-Disk Pack to the built-in SCSI port.
If you have a Multi-Disk Pack connected to the built-in SCSI host port of a SPARCstation 10 system with 2 internal disk drives running the Solaris 2.x operating system (SunOS 5.1) or a later release of the Solaris 2.x operating system, add the following cable lengths:
This totals 2.7 meters of cable, less than the 6 meter (20 feet) maximum for each SCSI bus.
If you have a Multi-Disk Pack and a Desktop SunCD Pack connected to a SPARCclassic system with 1 internal hard disk drive running the SunOS 5.1 operating system (or a later release of the operating system) add the following cable lengths:
This totals 3.5 meters of cable, less than the 6 meter (20 feet) maximum for each SCSI bus.
You must attach the regulated SCSI terminator (P/N 150-1785) to either of the SCSI ports of the Multi-Disk Pack or to the last SCSI peripheral in the SCSI chain. The regulated SCSI terminator resembles a SCSI cable plug without a cable, and is stamped "REGULATED." Figure A-5 shows a regulated SCSI terminator.
Figure A-5 Regulated SCSI Terminator
Follow these SCSI termination rules:
