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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

SCIOSTART (Start SCSI) Adapter Device Driver ioctl Operation


Opens a logical path to a SCSI target device.


The SCIOSTART operation opens a logical path to a SCSI device. The host SCSI adapter acts as an initiator device. This operation causes the adapter device driver to allocate and initialize the data areas needed to manage commands to a particular SCSI target.

The SCIOSTART operation must be issued prior to any of the other non-diagnostic mode operations, such as SCIOINQU and SCIORESET. However, the SCIOSTART operation is not required prior to calling the IOCINFO operation. Finally, when the caller is finished issuing commands to the SCSI target, the SCIOSTOP operation must be issued to release allocated data areas and close the path to the device.

The arg parameter to SCIOSTART allows the caller to specify the SCSI and LUN (logical unit number) identifier of the device to be started. The least significant byte in the arg parameter is the LUN, and the next least significant byte is the SCSI ID. The remaining two bytes are reserved and must be set to a value of 0.

Return Values

If completed successfully this operation returns a value of 0. Otherwise, a value of -1 is returned and the errno global variable set to one of the following values:

EIO Indicates either an unrecoverable I/O error, or the device driver is unable to pin code.
EINVAL Indicates either that the SCSI ID and LUN combination was incorrect (the combination may already be in use) or that the passed SCSI ID is the same as that of the adapter.

If the SCIOSTART operation is unsuccessful, the caller must not attempt other operations to this SCSI ID and LUN combination, since it is either already in use or was never successfully started.


/dev/scsi0, /dev/scsi1, ..., /dev/scsin Provide an interface to allow SCSI device drivers to access SCSI devices or adapters.
/dev/vscsi0, /dev/vscsi1,..., /dev/vscsin Provide an interface to allow SCSI-2 Fast/Wide Adapter/A and SCSI-2 Differential Fast/Wide Adapter/A device drivers to access SCSI devices or adapters.

Related Information

The rmt SCSI device driver, scdisk SCSI device driver, SCSI Adapter device driver.

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