This appendix describes technical information about the Small Computer Systems Interface (SCSI):
There are two basic methods of connecting the Multi-Disk Pack to your system:
Connecting the SCSI cable of the Multi-Disk Pack to the SCSI connector of your system.
Connecting the SCSI cable of the Desktop Storage Module to the SCSI connector of another SCSI device.
Use direct connection when you are connecting the first SCSI device in the SCSI bus to the computer system. If the computer system is running the Solaris 1.1 operating system (SunOS 4.1.3), refer to Table 1-2 in Chapter 1 for operating system requirements.
Connect one end of the SCSI cable to one of the SCSI host adapter ports on the SCSI peripheral and the other end of the SCSI cable to the SCSI host adapter of the computer system or to an installed SBus card with a SCSI host adapter port on it. Connect a regulated SCSI terminator to the other SCSI host adapter port on the SCSI peripheral.
Figure B-1 shows a Multi-Disk Pack connected directly to a SCSI host adapter port of an SBus card.
Figure B-1 Example of Direct Connection
A daisy-chain is a means of connecting a number of SCSI peripherals to a host adapter. One cable connects the host adapter to the nearest of the SCSI peripherals, and then a separate cable connects the first SCSI peripheral to the second SCSI peripheral. This process is repeated as required.
You can daisy-chain SCSI devices to the Multi-Disk Pack which meet the "fast SCSI" requirements. SCSI peripherals with SCSI host adapters containing 50 pins divided into two rows meet "fast SCSI" requirements. SCSI devices that do not have 2 rows of 50 pins on the SCSI host adapter do not meet the "fast SCSI" requirements.
If you daisy-chain SCSI peripherals to your system in this manner, connect the regulated terminator, supplied with the Multi-Disk Pack, to the unused SCSI host adapter on the last SCSI peripheral the daisy-chain. The total SCSI cable length (internal and external) should not exceed 6 meters (20 feet). Refer to Tables B-1 and B-2.
Caution -
Note - You cannot daisy-chain differential SCSI drives to a Multi-Disk Pack. You must use a DSBE/S SBus card with a differential SCSI disk drive.
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 of a SCSI bus is 20 feet (6 meters). Refer to Tables
B-1 and B-2. Sun SPARC
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:
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 directly to a SPARCserver 630 or 670 system, you will need a 79-inch (2.0 meter) SCSI cable. Refer to Chapter 4, "Illustrated Parts Breakdown" for the SCSI cable part number.
To directly connect a Multi-Disk Pack to a desktop SPARC system (such as a SPARCstation 2, 10, or IPX system) or to daisy-chain SCSI peripherals together, use the 32-inch (0.8 meter) SCSI cable supplied with the Multi-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 B-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 B-2 lists the internal SCSI cable lengths of supported computer systems.
Use Tables B-1 and B-2 to calculate the SCSI bus length.
Refer to Section B.2.5 "Calculating the SCSI Bus Length" for examples.
Table B-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 0* 0*
Desktop Storage Module 12 0.3
4.2 Gbyte 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
* The SCSI bus length of the Desktop Storage Pack is not significant.
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Table B-2 Internal Cable Lengths of Computer Systems Supported
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Computer Systems (Internal Cable Lengths) Inches Meters -----------------------------------------------------------------
SPARCstation 1, 1+, LX, and SPARCclassic systems 24 0.6
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 system TBD TBD
-----------------------------------------------------------------
This section provides examples describing how to calculate the SCSI bus length when connecting the Multi-Disk Pack to either an additional SCSI host adapter (on an SBus card) or to the built-in SCSI host adapter port of the computer system.
Note -
In order for the drives in the unit to operate at maximum performance,
you should make sure that the Multi-Disk Pack is the only unit connected to a
SCSI bus.
The unit should be connected to either a computer system which supports
"fast SCSI" on the built-in SCSI host adapter port or to an FSBE/S SBus card.
Refer to Table B-3.
Table B-3 Hardware Requirements
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System Built-in SCSI SCSI Host SCSI Host Host Adapter Speed Adapter cards Adapter cards** (Mbytes per second) 5 Mbyte/sec 10 Mbyte/sec SCSI-2 transfer SCSI-2 transfer rate rate --------------------------------------------------------------------------------------------------------------------------------------------
SPARCstation 1 system Not supported SSHA* FSBE/S
SPARCstation 1+ system Not supported SSHA* FSBE/S
SPARCstation IPC system 5 SSHA* FSBE/S
SPARCstation IPX system 5 SSHA* FSBE/S
SPARCstation 2 system 5 SSHA* FSBE/S
SPARCstation 10 system 10 SBE/S, SSHA* FSBE/S
SPARCstation ELC system 5 No SBus slots No SBus slots
Not supported Not supported
SPARCstation SLC system 5 No SBus slots No SBus slots
Not supported Not supported
SPARCstation LX system 10 SSHA* FSBE/S
SPARCclassic system 10 SSHA* FSBE/S
SPARCserver 630 system 5 (early models) SBE/S FSBE/S
10 (later models)
SPARCserver 670 system 5 (early models) SBE/S FSBE/S
10 (later models)
* SSHA is the SBus SCSI Host Adapter SBus card. Requires boot PROM version 1.3 or
higher. To boot from the SSHA, requires boot PROM version 2.0 or higher.
** FSBE/S requires boot PROM version 2.0 or higher.
--------------------------------------------------------------------------------------------------------------------------------------------
Refer to Table B-3 for the supported SCSI host adapters for your
computer system.
If you have a Multi-Disk Pack, a Desktop Backup Pack, and a Desktop
SunCD Pack connected to a FSBE/S SBus card, add the following
cable lengths:
This totals 3.4 meters of cable, less than the 6 meter (20 feet) maximum for each SCSI bus.
If you have a Desktop Storage Module tape unit and a Multi-Disk Pack connected to a FSBE/S SBus card, add the following cable lengths:
This totals 2.9 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 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 onboard SCSI host adapter.
Refer to Table B-3 in this appendix for the supported SCSI host adapters for your computer system.
If you have a Multi-Disk Pack connected to the onboard SCSI host adapter of a SPARCstation 10 (with 2 internal disk drives (running SunOS 5.1 or a later release of the 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 operating system release) add the following cable lengths:
This totals 3.2 meters of cable, less than the 6 meter (20 feet) maximum for each SCSI bus.
You must attach the regulated SCSI terminator, supplied with the Multi-Disk Pack, to either of the SCSI host adapter ports of the Multi-Disk Pack or to the last SCSI peripheral in the SCSI chain. The word "REGULATED" is stamped on a regulated terminator. The regulated SCSI terminator resembles a SCSI cable plug without a cable. Figures B-2 and B-3 illustrate a regulated SCSI terminator and a SCSI host adapter port on the Multi-Disk Pack.
Figure B-2 Regulated SCSI Terminator
Figure B-3 SCSI Host Adapter Port on Multi-Disk Pack Back Panel
Follow these SCSI termination rules:
