Windows NT Stops Responding with DPT PM2124 SCSI Adapter (151877)

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Older versions of the DPT PM2124 SCSI Adapter firmware have been identified as having a problem when a flush command is sent and then followed by a large number of queued requests. When this problem is encountered, the LED indicators on the adapter scan back and forth, indicating an idle condition on the SCSI adapter. Yet there are queued requests in the Windows NT I/O subsystem that are waiting on the adapter to complete the request that triggered the error condition.

Because of this "deadlock" situation, disk requests will go unfulfilled and applications or services which require disk I/O will be blocked. In some cases, this situation may correct itself one or more times without specific user intervention, resulting only in degraded system performance and symptoms similar to a memory leak while I/O is being blocked. Other times, the system will remain blocked indefinitely, resulting in services and applications failing one by one until the entire system is blocked. Even the keyboard and mouse may eventually stop responding. It is interesting to note, however, that the very lowest level network drivers may still be running. This means, for example, that if TCP/IP is used on the system, it will still be possible to PING the system, but higher level protocols will no longer function.

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