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Wide SCSI Support
Version 1.0 - December 19, 1995
NOTE: Devices and revisions cited were accurate when this document
was prepared.
For the latest information, see the SOC
archives.
Contents
Introduction
AlphaServer 8200 and 8400 systems now support wide (16-bit) SCSI devices.
Wide SCSI disks can improve the performance of applications that need
very high bandwidth I/O data transfers. Also, 16-bit devices allow migration
to the newest PCI SCSI controllers.
System Requirements for Wide
Operation
Four system elements are required for wide operation:
- Wide drives
- Wide shelves/PIUs
- Wide controllers
- Cables and terminators
Wide Drives
The following 3.5-inch wide drives are supported on AlphaServer 8200/8400
systems:
- RZ26L-VW 1.05 GB
- RZ26N-VW 1.05 GB
- RZ28-VW 2.1 GB
- RZ28D-VW 2.1 GB
- RZ28M-VW 2.1 GB
- RZ29B-VW 4.3 GB
Wide Shelves/PIUs
Wide (16-bit) SCSI drives require wide SCSI shelves. To configure wide
SCSI devices in the system and expander cabinets, you need:
- For the 8200, the new BA356-JB wide SCSI shelf
NOTE: The BA656 storage drawer is a narrow "shelf."
Only narrow (-VA) drives can be installed. All RZxx-VA drives currently
supported in AlphaServer 8200/8400 systems can be used, including the
RZ29B-VA.
- For the 8400, the new BA660-AB option for configuring embedded wide
devices inside the systems enclosure, or, the BA661-AA option for DWLPA
PCI-based configurations.
Some narrow (8-bit) SCSI devices will also work in wide shelves and
can be mixed with wide (16-bit) SCSI devices. These narrow drives must
have the recommended minimum revision level firmware as defined by the
Storage Systems organization and will always run in 8-bit mode even when
connected to a wide SCSI controller.
Wide Controllers
The following SCSI controllers allow wide devices to operate in 16-bit
mode:
- KFTIA - Three fast wide differential ports on the system I/O module
- KZPSC - Fast wide controller for either RAID array or native SCSI
operation
- KZPSA - Fast wide differential connection to disks in BA35x- shelves.
Supports DECsafe high-availability environments.
Cables and Terminators
Requirements for cables and terminators depend on the particular platform
and controller. See Rules for Cables and
Terminators .
The sections describing specific drives list the minimum revisions of
operating system software and console firmware required to support the
various SCSI devices and controllers.
Mixing Narrow and Wide
Devices, Controllers, and Shelves
Wide drives can ONLY be used in wide shelves. However,
wide drives can operate in narrow (8-bit) mode when connected to a narrow
SCSI controller such as the single-ended KFTIA port. There is no performance
advantage to running wide drives in 8-bit mode.
Narrow devices will work in wide shelves and can be mixed with wide
devices. The narrow devices always run in 8-bit mode, even when connected
to a wide SCSI controller. Minimum revision levels for the narrow devices
are defined by the Storage Systems organization.
Combinations of controllers, shelves, wide and narrow drives, and cables
are permitted but only when ALL components are wide will wide mode
be in effect.
Controller Shelf Drive Cables Mode
N N N N N
N W N N N
N W W N N
W N N W/N N
W W N W N
W W W W W
N = narrow, W = wide
Frequently Asked Questions
- Q: Can a narrow device plug into a wide shelf?
A: Yes, the physical connections on the wide and narrow
StorageWorks Building Blocks (SBBs) are the same. However, the device
must be at the correct revision level. These revision levels are clearly
labeled on the side of the SBB. For example, all narrow disk drives
shipped in SBB since Nov. 1993 will function properly as a narrow disk
drive when installed in a wide shelf.
- Q: Can narrow and wide devices be mixed into a wide
shelf?
A: Yes. If the controller is narrow, all drives run
in narrow mode. If the controller is wide, wide drives run in wide mode
and narrow drives run in narrow mode.
- Q: Can a wide device plug into a narrow shelf? What
happens if it is plugged in?
A: No! The device would not be seen by the console.
- Q: Can narrow shelves and wide shelves be mixed in
the same cabinet?
A: Yes. Narrow drives must be in the narrow (lower
address bits) shelf.
- Q Are wide devices clearly labeled so that they can
be easily identified?
A: Yes, on the front of the StorageWorks Building Block
(SBB) bezel.
- Q: Are there wide and narrow choices for all devices
(including disks/tapes/CD/loader)?
A: The strategy is to provide both wide and narrow
devices at the system building block (SSB) level for all devices, as
wide devices become available. (Currently, only disks are available.)
- Q: Can wide and narrow add-on storage enclosures
be attached to the same system?
A: If the system configuration rules permit it. Requires
special adapter cables or boards if wide and narrow shelves are daisy
chained. Requires that system supports both wide and narrow SCSI.
- Q: Can customers with narrow devices convert these
to plug into wide shelves and will they function properly?
A: Yes, see answer 2.
- Q: What functional/performance advantages will customers
see when they use wide drives without wide controllers?
A: There will be neither a functional nor performance
advantage. However, once the wide device is operated in wide mode on
a wide controller, there will be an improvement in the data throughput
performance, depending on the configuration and the application.
Configuration Rules
Rules for Narrow
Drives
- Can be used in narrow or wide shelves. If wide drives are in the same
shelf, the narrow drives must be at a minimum device revision level
as defined by the Storage Systems organization. (Wide drives would not
be seen by the console firmware or the operating system if an older
narrow drive were present.)
- Can be used with HSD05/HSD10.
- Can be used with wide controllers such as KZPSA and KZPSC; drive runs
in narrow mode.
- Can be installed behind DWZZA and DWZZB.
Rules for Wide Drives
- Can ONLY be used in wide shelves.
- Cannot be used behind HSD05/HSD10. Wide drives will not be seen at
console or operating system level.
- Cannot be used in a shelf with any narrow drive having a revision
level less than that listed in the revision matrix.
Console and Operating
System Revision Requirements
These drives have been added to the AlphaServer
8200/8400 on-line supported options list and must be used in the BA356-JB
(8200), BA660-AB (8400) or BA661-AA (8400 DWLPA sys) wide SCSI shelves/PIUs
for 16-bit mode operation.
Device Levels Description Minimum Rev.
RZ26L-VW 1.05 GB 3.5" wide drive Rev. 442E or later f/w
Tru64 UNIX V3.2C
OpenVMS V6.2
RZ26N-VW 1.05 GB 3.5" wide drive Rev. 568 or later f/w
Tru64 UNIX V3.2C
OpenVMS V6.2
RZ28-VW 2.1 GB 3.5" wide drive Rev. 442E or later f/w
Tru64 UNIX V3.2C
OpenVMS V6.2
RZ28D-VW 2.1 GB 3.5" wide drive Rev. 8 or later f/w
Tru64 UNIX V3.2C
OpenVMS V6.2
RZ28M-VW 2.1 GB 3.5" wide drive Rev. 568 or later f/w
Tru64 UNIX V3.2C
OpenVMS V6.2
RZ29B-VW 4.3 GB 3.5" wide drive Rev. 14 or later f/w
Tru64 UNIX V3.2C
OpenVMS V6.2
Rules for Shelves
Rules for Narrow Shelves
AlphaServer 8200 narrow shelf - BA350-JB
(the BA656 storage drawer is also narrow)
AlphaServer 8400 narrow storage plug-in units - BA655-AB and BA658-AA
- Narrow drives only
- Can use DWZZA
- Can use HSD05/HSD10
Wide Shelves
The supported wide shelves include the 48V DC 150 watt power supply.
AlphaServer 8200 wide shelf - BA356-JB
AlphaServer 8400 wide storage plug-in units - BA660-AB, BA661-AA
These shelves are used in the system and expander cabinets; other variants
are used in the SW500/800 cabinets.
Rules for Wide Shelves
- Can use both wide and narrow drives. Narrow drives must be at a minimum
revision as defined by the Storage Systems organization if both narrow
and wide drives are in the same shelf. Otherwise, the wide drives will
not be seen at the console or at the operating system level. (All narrow
drives will be seen.)
- Can use DWZZB.
- Can use HSD05/HSD10 if all drives in the shelf are narrow.
- Split bus/shelf configuration requires that a terminator module be
ordered (BA35X-ME).
- Left-most connector (on recessed side) of Personality module is input
connector and right-most connector (at front) of Personality module
is output connector, for daisy-chaining/expanding enclosures. Personality
card provides bus termination for the enclosure. Plugging a cable into
the right-most connector disables the termination.
OpenVMS and Tru64 UNIX currently support only IDs 0-7.
Rules for Controllers
The following SCSI controllers can be used with both narrow and wide
SCSI devices:
KFTIA - Integrated I/O Module
- Three fast wide differential SCSI ports on each module.
- Must connect to either a DWZZA or DWZZB.
- CK-KFTIA-AA cabinet kit for FWD SCSI ports used. Kit includes Y-cable
and FWD SCSI terminator.
- Minimum supported operating system:
- OpenVMS V6.2
- Tru64 UNIX V3.2C
KZPSA - PCI Fast Wide Differential
SCSI Controller
- Controller is fast wide, so must connect to either a DWZZA or DWZZB.
- Minimum supported operating system:
- OpenVMS V6.2
- Tru64 UNIX V3.2C
- HW = F01, FW = A09
KZPSC - PCI RAID Controller
- Controller can run either fast wide single-ended or fast narrow single-ended.
In mixed (wide/narrow) drive configurations, the controller will negotiate
to capabilities of individual drives.
- In a mixed (narrow/wide) configuration, if the wide drives are not
seen and a drive appears with FMT (format required) status (seen at
the RAID Configuration Unit Level), then the drive is not at the correct
revision level.
- Adapter plug (H4086-AA) required to cable to narrow internal shelf.
- Each channel supports SCSI IDs 0-7.
- A total of 8 logical drives can be created per controller.
- Wide drives require wide shelves.
- Minimum supported operating system:
- OpenVMS V6.2 (supports host-based shadowing support and on-line
GUI monitor utilities).
- Tru64 UNIX V3.2C
- HW = B01, FW = 2.19
RAID Standalone Configuration Utility (RCU)
V3.08 for Rev V3.xx console
V3.11 for Rev V4.xx of console (backward compatible)
DWZZA - Fast Wide Differential
to Fast Narrow Single-Ended Converter
- Slot 0 for -VA version
- Minimum revision level: DWZZA-AA/VA E02/F02
- Used only in narrow shelves.
DWZZB - Fast Wide Differential
to Fast Wide Single-Ended Converter
- Slot 0 for -VW version.
- Minimum revision level: DWZZB-AA/VW A01/A01
- Used only in wide shelves.
- Supports both narrow and wide drives.
Rules for Cables and
Terminators
KFTIA Cables
From KFTIA fast wide differential port to BA660-AB, BA661-AA, and BA356-JB
system cabinet or expander cabinet:
KZPSA External Cables
- BN21K-** from KZPSA to DWZZA or DWZZB (straight to right angle)
- BN21W-0B Y SCSI-2 cable 68 pins for using KZPSA in mid-bus (daisy-chained)
configurations
** = Variants depend on cable length.
KZPSC External Cables
- BN31L-1E from KZPSC to BA350 (narrow shelf)
- BN31S-1E from KZPSC to BA356 (wide shelf)
Cable Length
The maximum cable length for the SCSI-2 bus depends on whether it is
fast or slow, single-ended or differential.
Fast Slow
*Single Ended 3 meters 6 meters
(9 feet) (18 feet)
Differential 25 meters 25 meters
(75 feet) (75 feet)
* This includes .5 meter cable length used inside the systems. The BA35X
includes 1.0 meter internal etch.
Terminators
- H879-AA SCSI-3 Terminator Block 68-pin male passive terminator (terminates
the end of a wide differential bus)
- H8862-AA (Future) 68-pin active terminator (terminates the end of
a wide single-ended bus)
- H885-AA SCSI-3 68-pin tri-link connector block for DWZZA/DWZZB
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