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Writing Device Drivers
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SCSI Options

SCSA defines a global variable, scsi_options, for control and debugging. The defined bits in scsi_options can be found in the file <sys/scsi/conf/autoconf.h>. The scsi_options uses the bits as follows:


Enables global disconnect or reconnect.


Enables global FAST SCSI support: 10 Mbytes/sec transfers. The HBA should not operate in FAST SCSI mode unless the SCSI_OPTIONS_FAST (0x100) bit is set.


Enables global FAST20 SCSI support: 20 Mbytes/sec transfers. The HBA should not operate in FAST20 SCSI mode unless the SCSI_OPTIONS_FAST20 (0x400) bit is set.


Enables global FAST40 SCSI support: 40 Mbytes/sec transfers. The HBA should not operate in FAST40 SCSI mode unless the SCSI_OPTIONS_FAST40 (0x800) bit is set.


Enables global FAST80 SCSI support: 80 Mbytes/sec transfers. The HBA should not operate in FAST80 SCSI mode unless the SCSI_OPTIONS_FAST80 (0x1000) bit is set.


Enables global FAST160 SCSI support: 160 Mbytes/sec transfers. The HBA should not operate in FAST160 SCSI mode unless the SCSI_OPTIONS_FAST160 (0x2000) bit is set.


Enables global FAST320 SCSI support: 320 Mbytes/sec transfers. The HBA should not operate in FAST320 SCSI mode unless the SCSI_OPTIONS_FAST320 (0x4000) bit is set.


Enables global link support.


Enables global parity support.


Enables the Quick Arbitration Select feature. QAS is used to decrease protocol overhead when devices arbitrate for and access the bus. QAS is only supported on Ultra4 (FAST160) SCSI devices, although not all such devices support QAS. The HBA should not operate in QAS SCSI mode unless the SCSI_OPTIONS_QAS (0x100000) bit is set. Consult the appropriate Sun hardware documentation to determine whether your machine supports QAS.


Enables global synchronous transfer capability.


Enables global tagged queuing support.


Enables global WIDE SCSI.

Note - The setting of scsi_options affects all host bus adapter drivers and all target drivers that are present on the system. Refer to the scsi_hba_attach(9F) man page for information on controlling these options for a particular host adapter.

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  Published under the terms fo the Public Documentation License Version 1.01. Design by Interspire