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Attaches Single-Ended SCSI devices to a Low Voltage Differential (LVD) SCSI Bus
- Operates as a SCSI Bus Converter or Repeater
- Provides SCSI Bus electrical isolation for high availability and scalable server clustering technologies
- Targets and initiators can be located on either the A-side or B-side of the device
- Via the pin level electrical isolation mode, each side of the device can be logically disconnected from the other
- Dynamic mode switching used to inform initiators of transmission mode change
- Self-calibration mode supports variations in voltage, temperature, and silicon process
- Accepts any asynchronous or synchronous transfer speed up to Ultra SCSI
- Does not consume a SCSI ID
- On-chip multi-mode LVDlink™ transceivers
- Supports TolerANT? transceiver Technology
- Can cascade up to three IOI-141LSs
- Complete support for SCSI-1, -2, & -3
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IOI-141LS SCSI Bus expander allows extension of device connectivity and/or cable length limits of the SCSI bus. SCSI bus expanders are the way servers are clustered. A SCSI bus expander couples bus segments together without any impact to the SCSI protocol, software, or firmware. The IOI-141LS SCSI bus expander attaches Single-Ended (SE) SCSI peripherals to the Low Voltage Differential(LVD signaling bus used by Ultra2 SCSI.
The IOI-141LS enables system architects to take advantage of the inherent cable distance, device connectivity, and signaling while operation with peripherals designed for Ultra SCSI speeds.
The IOI-141LS provides additional control capability through the pin level electrical isolation mode. This feature allows logical disconnection of both the A side bus and B side bus without disrupting SCSI transfers currently in progress. For example, devices on the logically disconnected B side can swapped out while the A side bus remains active.
The IOI-141LS is based upon bus expander technology resulting in some signal filtering and retiming in some signal filtering and retiming to maintain signal skew budgets. In addition, the IOI-141LS has no programmable registers, therefore it does not require any software.
The IOI-141LS operates in two mode:
Single-Ended to Single-Ended (Repeater), or
Single-Ended to Low Voltage Differential (Converter).
LVDLink Technology
To support greater device connectivity and a longer SCSI cable, the IOI-141LS features LVDlink technology, the Symbios Logic implementation of Universal LVD SCSI. LVDlink transceivers provide the inherent reliability of differential SCSI, and a long-term migration path of faster SCSI transfer rates. LVDlink lowers the amplitude of noise reflections and allows higher transmission frequencies.
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TolerANT Technology
The IOI-141LS feature TolerANT technology, which includes active negation on the SCSI drivers and input signal filtering on the SCSI receivers. Active negation causes the SCSI Request, Acknowledge, Data, and Parity signals to be actively driven high rather than passively pulled up by terminators.
TolerANT receiver technology improves data integrity in unreliable cabling environments, where other devices would be subject to data corruption. TolerANT receivers filter the SCSI bus signals to eliminate unwanted transitions, without the long signal delay associated with RC-type input filters. This improved driver and receiver technology helps eliminate double clocking of data, the single biggest reliability issue with SCSI operations.
The benefits of TolerANT include increased immunity to noise on the de-asserting signal edge, better performance due to balanced duty cycles, and improved SCSI devices prevent glitches on the SCSI bus at power-up or power-down, so other devices on the bus are also protected from data corruption.
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