CHAPTER 3: Before You Install: Getting Started

NOTE

If you mix Wide and Narrow devices on the same side (internal or external) of a SCSI bus attached to the Adapter, we strongly recommend that all of the Narrow devices be attached to the bus closer to the Adapter than all of the Wide devices. If you attach any Narrow devices at the far end of the bus, beyond any Wide devices, you’ll have to be very careful to terminate the Wide lines (Pins 51 to 68) of the last Wide device.

Alternatively, you can “hardwire” the Adapter so that termination is always ON by installing jumpers on the Adapter’s circuit board. The most common application for which you would hardwire-enable termination is this: installing multiple Adapters in multiple PCs, but attaching them to the same bus in order to share peripherals. In such situations, you might want to hardwire termination ON for any Adapters that are on the end of the bus, so that you can turn off the computers in which those Adapters are installed without losing termination power and disabling the SCSI bus. If for this (or whatever) reason you do want to hardwire termination ON, you need to install a jumper on the Adapter before you put it in your PC. (Once this jumper is installed, it will override the termination setting in the Adapter’s firmware.) The jumper should be installed at location JP1, as shown in Figure 3-3 below.

JP1 TERMINATION

1–2 Always OFF

NO JMP SW CNTRL < Default >

JP1:

Termination

Jumper

VCC

+

VCC

LED

LED

1

4

ACT

 

 

TERM

 

 

LVD

 

 

SE

Figure 3-3. Hardwiring termination.

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Image 20
Black Box SCSI-2 LVD manual Hardwiring termination

SCSI-2 LVD specifications

The Black Box SCSI-2 LVD (Low Voltage Differential) represents a significant advancement in data storage and connectivity technology, particularly in environments requiring high performance and reliability. As a variant of the SCSI (Small Computer System Interface) standard, it is optimized for faster data communication, essential for modern computing needs.

One of the main features of SCSI-2 LVD is its capability to handle increased data transfer speeds compared to its predecessors. It supports a maximum data transfer rate of up to 80 MB/s, which is double that of the original SCSI-2 single-ended signaling. This increase in speed is largely due to the differential signaling that LVD employs, allowing for reduced electromagnetic interference and extended cable lengths while maintaining signal integrity. The technology effectively converts the SCSI bus into a more robust system that can accommodate various devices without compromising performance.

The SCSI-2 LVD standard is backward compatible, meaning that it can interface with older SCSI devices, albeit at reduced speeds. This compatibility is significant for users looking to upgrade their systems without discarding existing hardware. This makes SCSI-2 LVD an attractive choice for enterprise environments where legacy systems are common.

Another key characteristic is the flexible cabling options provided by SCSI-2 LVD. It can support cable lengths of up to 12 meters, which is beneficial for large data center configurations where space between devices can be substantial. This extended range does not typically come at the expense of performance, ensuring that data integrity remains high, even over longer distances.

In terms of technology, LVD employs lower voltage levels, which not only contributes to greater power efficiency but also minimizes heat generation in devices. This is particularly crucial in data centers where temperature management can impact hardware longevity and reliability. The combination of lower voltage use and differential signaling makes SCSI-2 LVD well-suited for high-density environments.

Error correction and handshaking features are also integral to SCSI-2 LVD, enhancing its robustness against data loss during transmission. These characteristics make it a reliable choice for applications requiring consistent and high-speed data access, such as server arrays and high-performance computing tasks.

Overall, Black Box SCSI-2 LVD stands out due to its impressive speed, compatibility, and extensive cabling options, positioning it as a reliable solution for demanding data environments. It effectively bridges the gap between legacy systems and modern technology, ensuring that users can optimize their data handling capabilities without significant disruption.