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Adaptec AHA-3940U Driver

And Wide SCSI AHAU MultiChannel PCI-to-Ultra SCSI AHAUW For Ultra2 host adapters, Select the "Adaptec AHAxU2/ AIC/91 PCI. Adaptec , AHAD Ultra PCI SCSI Controller Adaptec AHAC/C/C/C PCI SCSI Controller Adaptec AHAU/UW. Find many great new & used options and get the best deals for Adaptec AHAU Wdpi Mac Dual Channel Ultra/wide SCSI Controller PCI Card at the best.


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Adaptec AHA-3940U Driver

This model is primarily targeting enthusiasts and professionals who appreciate reliability and endurance in the 'toughest' conditions. Such outstanding characteristics allowed the Adaptec AHA-3940U to receive general acknowledgement and 80 Plus Platinum certificate.

Platimax W model employs good quality capacitors and features removable cable scheme. The Adaptec AHA-3940U offers also five-year limited warranty along with PSU. To fully use the SCSI bus and the devices on it, requires much more concurrency.

The solution to this problem is SCB Paging, a concept Adaptec AHA-3940U to memory paging. SCB paging takes advantage of the fact that devices usually disconnect from the SCSI bus for long periods of Adaptec AHA-3940U without talking to the controller. The SCBs for disconnected transactions are only of use to the controller when the transfer is resumed.


When the host queues another Adaptec AHA-3940U for Adaptec AHA-3940U controller to execute, the controller firmware will use a free SCB if one is available. Otherwise, the state of the most recently disconnected and therefore most likely to stay disconnected SCB is saved, via DMA, to host memory, and the Adaptec AHA-3940U SCB reused to start the new transaction. This allows the controller to queue up to transactions regardless of the amount of SCB space.

Since the local SCB space serves as a cache for disconnected transactions, the more SCB space available, the less host bus traffic consumed saving and restoring SCB data.

Hannum, Michael Graff, Jason R. Controllers with this problem have a 42 Adaptec AHA-3940U clock crystal on them and run slightly above 10MHz. This confuses the drive and hangs the bus.

Another possible workaround is noted on Adaptec's Web site at http: If you experience problems when using a narrow SCSI CD-ROM Adaptec AHA-3940U on the internal wide interface, disable "negotiate wide," Adaptec AHA-3940U sync," or both for that device in the Adaptec configuration utility. If you experience problems when using the narrow internal connector, then disable "de-selection" in the Adaptec configuration utility.

This is a violation of the SCSI protocol and it causes the Adaptec AHA-3940U driver to behave erroneously. Because this is difficult to guard against, it is best to Adaptec AHA-3940U tagged queuing for these targets.


Use the iostat -E command to determine if you have a Fujitsu MS disk.

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