Microsoft KB Archive/137247

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IOCTL_SCSI_MINIPORT and IOCTL_SCSI_PASS_THROUGH Limitations

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Q137247

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The information in this article applies to:


 * Microsoft Win32 Device Driver Kit (DDK) for Windows NT, version 3.5

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SUMMARY
The device control codes IOCTL_SCSI_MINIPORT and IOCTL_SCSI_PASS_THROUGH require that a valid SCSI device be previously recognized before the IOCTL can be passed on to the SCSI miniport. In other words, SCSIPORT must have previously located a SCSI peripheral on the specific bus that the SCSI miniport supports or these IOCTLs will not be passed on.

MORE INFORMATION
A SCSI peripheral will be recognized by SCSIPORT when the system boots. Additionally, an IOCTL_SCSI_RESCAN_BUS sent to SCSIPORT will force SCSIPORT to re-scan the SCSI bus for new peripherals. Once a peripheral is recognized on a particular SCSI bus, IOCTL_SCSI_MINIPORT and IOCTL_SCSI_PASS_THROUGH can be sent to the miniport supporting that SCSI bus.

Note that IOCTL_SCSI_RESCAN_BUS can be sent to SCSIPORT and the SCSI miniport regardless of whether there are any SCSI devices currently present.