ATTO Technology operation manual Cable types, Examples, Connectors

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3.1 Determining cabling and termination

Cables and devices must be chosen to maximize performance and minimize the electrical noise from the high-speed data transfers available with the SCSI protocol. Cabling and termination methods become important considerations for proper performance. SCSI cables and devices are subject to specific length and number limitations to deal with electrical problems that arise at increased operating speeds.

Cable types

Single-ended and differential SCSI host adapters use the same cables. Use high-quality cables rated for the type of SCSI transfers required: well- insulated SCSI cables ensure error free communications. Try to keep cable lengths as short as possible to ensure higher signal quality and performance.

Examples

The SCSI specification limits total bus cable length for Single-Ended SCSI in a non-UltraSCSI

environment to 3 meters (combined length of both internal and external cable lengths).

In an UltraSCSI workgroup environment with a 7- drive tower, you are limited to 1.5 meters between the host and the tower, including the cabling for the tower. If the 7-drive tower requires 1 meter of cabling to connect all of its drives, the distance from the tower to the host must be .5 meters.

NOTE UltraSCSI is very sensitive to SCSI bus noise, cable distances and the number of devices connected on the SCSI bus. Carefully connect your devices when working with UltraSCSI.

Exhibit 3.1-1 Various types of SCSI require different bus lengths to support a certain number of devices.

 

Bus speed

Bus width

Max. bus lengths, meters

 

Max. device

STA terms

MB/sec. max.

bits

 

 

 

 

support

Single-ended

Differential

 

LVD

 

 

 

 

 

 

 

 

 

 

 

 

 

Fast SCSI

10

8

3

25

 

12

8

 

 

 

 

 

 

 

 

Fast/WIDE SCSI

20

16

3

25

 

12

16

 

 

 

 

 

 

 

 

UltraSCSI

20

8

1.5

25

 

12

8

 

 

 

 

 

 

 

 

UltraSCSI

20

8

3

n/a

 

n/a

4

 

 

 

 

 

 

 

 

Ultra/WIDE SCSI

40

16

n/a

25

 

12

16

 

 

 

 

 

 

 

 

Ultra/WIDE SCSI

40

16

1.5

n/a

 

n/a

8

 

 

 

 

 

 

 

 

Ultra/WIDE SCSI

40

16

3

n/a

 

n/a

4

 

 

 

 

 

 

 

 

Ultra2 SCSI

80

16

n/a

n/a

 

12

8

 

 

 

 

 

 

 

 

Ultra2/WIDE SCSI

80

16

n/a

n/a

 

12

16

 

 

 

 

 

 

 

 

Connectors

ATTO ExpressPCI PSC: one industry standard 68- pin “P” (16-bit) and one 50-pin (8-bit) cable connector for internal device connections and one 68-pin “P” (16-bit) cable connector for external device connections.

ATTO ExpressPCI DC: two industry standard 68- pin “P” (16-bit) cable connectors for internal

device connections and two 68-pin “P” (16-bit) VHDCI (Very High Density Cabled Interconnect) cable connectors for external device connections.

NOTE When installing SCSI devices on the ATTO ExpressPCI PSC, use any two SCSI ports on your ATTO ExpressPCI SCSI adapter, but not all three. Use all four channels on the ATTO ExpressPCI DC.

7 ATTO Technology ExpressPCI Ultra/WIDE SCSI Host Adapters Installation and Operation Manual

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Contents Page Page Contents Environmental and Physical Specifications FeaturesPower Requirements Scsi ConnectorsFeatures, benefits Scsi is a key technology for storage GlossaryGlossary Installation Installing the ExpressPCI Scsi Host AdapterSystem requirements Atto ExpressPCI PSC Scsi adapter Cable types ConnectorsExamples Connection considerations TerminationTo set up cabling and termination Wide devices first closest to the connectorCables, termination Installing and Updating Device Drivers Windows Server 2003 & Windows 2000/XPDrivers Re-flashing Firmware in Windows Updating Drivers and Re-flashing Firmware in Mac OS Use the latest Atto driver Set up RAID groups with Atto ExpressRAIDSet registry for large block transfers Increase transfer size Analyze your I/OsTroubleshooting Troubleshooting Appendix a Standards and compliances FCC standards radio and television interferenceSpecific features Appendix B Scsi host adapter selection guideAppendix C Fibre Channel host adapter guide ExpressPCI Express PCIAppendix D Contact Atto Technology, Inc

ATTO ExpressPCI Ultra/WIDE SCSI Host Adapters Express PCI PSC: Single-Channel Single-Ended Ultra/WIDE ExpressPCI DC: Dual-Channel Single-Ended Ultra/WIDE specifications

ATTO Technology is a leading provider of cutting-edge storage connectivity solutions, and their line of ATTO ExpressPCI Ultra/WIDE SCSI Host Adapters has showcased the company’s commitment to performance and reliability for demanding data applications. Specifically, the ExpressPCI PSC (Single-Channel Single-Ended Ultra/WIDE) and the ExpressPCI DC (Dual-Channel Single-Ended Ultra/WIDE) models cater to different user needs while maintaining industry standards.

The ATTO ExpressPCI PSC is designed for environments where a single channel is sufficient to meet the connectivity demands. This single-ended adapter supports Ultra/WIDE SCSI technology, enabling data transfer rates of up to 40 MB/s. The PSC is perfect for users who require efficient storage solutions without the complexity of handling multiple channels. With its robust design, this adapter excels in various applications, from small business servers to high-performance workstations, offering reliability in demanding environments.

On the other hand, the ATTO ExpressPCI DC doubles the capability with its dual-channel architecture. This feature allows for two independent SCSI buses, effectively doubling the potential data throughput. By utilizing ultra/WIDE SCSI technology, the DC can achieve a combined throughput of 80 MB/s, making it an optimal choice for users needing higher performance for tasks such as video editing, data intensive applications, and backups. The dual-channel configuration provides advantages in multitasking, enabling the simultaneous operation of multiple drives or devices.

Both models incorporate advanced technologies such as automatic bus termination and active negation, ensuring optimal signal integrity and reliability. Additionally, ATTO’s exclusive Advanced Data Flow Management technology enhances performance by intelligently managing data transfer to optimize bandwidth utilization, which is key in environments where data transfer speed and reliability are crucial.

Another noteworthy characteristic is the high compatibility with various operating systems and SCSI devices, making the ExpressPCI Ultra/WIDE SCSI Host Adapters versatile and easy to incorporate into existing systems. They support a wide range of SCSI drives and peripherals, ensuring that users can leverage their investment in both current and future technologies. In summary, the ATTO ExpressPCI Ultra/WIDE SCSI Host Adapters—PSC and DC—represent robust solutions that blend speed, reliability, and flexibility, catering to the diverse needs of businesses and advanced users alike. With their proven performance, these adapters continue to be an important asset in high-demand data environments, showcasing ATTO's dedication to innovation in the storage connectivity realm.
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