For support of Adaptec's family of Ultra2 SCSI products for the PCI bus, please refer to the adsb(7) manual page. This includes the AHA-2940U2W, AHA-2940U2B, AHA-2950U2B, and AHA-3950U2x host adapters, and motherboards using the AIC-7890, AIC-7891, AIC-7896, and AIC-7897 Ultra2 SCSI chips.
This driver is complaint with the Storage Device Interface (SDI), enabling SDI-compliant target drivers (such as sd01 and st01) to communicate on the SCSI bus with target controllers and logical units. This allows normal access to mass-storage devices using standard system interfaces and filesystems.
It is also possible for an application to access the SCSI bus subsystem directly by using the pass-through interface. See pt_open(3X). Exercise extreme caution when using the pass-through interface. It is possible to interfere with normal system I/O and cause hangs if pass-through is used to an active device. Pass-through should only be used to a device that is otherwise quiescent.
The Adaptec PCI host adapter driver honors the command timeout values as specified in the scb structure; see the scb(D4sdi) manual page. A software watchdog timer enforces the processing time limit. When the watchdog timer detects a job that has exceeded its processing time limit, it attempts to abort the job with a SCSI Job Abort Message. The driver also enforces a time limit on the abort process, thereby ensuring that jobs that ``time out'' are reported to the sending SDI Target Driver whether or not the abort succeeds.