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HP-UX Reference Volume 5 of 5 > s
scsi(7) |
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NAMEscsi — Small Computer System Interface device drivers DESCRIPTIONThe Small Computer System Interface (SCSI) is an American National Standard for interconnecting computers and peripheral devices. HP-UX supports the SCSI device protocol on parallel SCSI interfaces (see ANSI Std X3.131-199X, ``SCSI-2'') and Fibre Channel interfaces (see ANSI Std X3.269-199X, "Fibre Channel Protocol for SCSI"). The SCSI standard includes specifications for a variety of device types. This section describes the general SCSI interface for all SCSI device drivers. Information about specific device types can be found in the manual sections which describe SCSI peripheral device drivers for those device types. The SIOC_INQUIRY ioctl is supported by all SCSI device drivers. This ioctl returns the SCSI device-specific INQUIRY command data. This data contains device identification and capability information. Since there have been multiple versions of the SCSI standard for inquiry data, multiple versions of the inquiry data declaration are provided. The SCSI-1 version is provided for backward compatibility only. The SIOC_CAPACITY ioctl indicates the current device size. A device size is defined to be a logical block size and some number of logical blocks. The means of determining this device-size data is particular to the specific device type. Logical block size and/or number of logical blocks equal to zero indicates: the device size is unknown, the device is not currently capable of I/O operations, or I/O operations are not meaningful for the device. Note that DIOC_CAPACITY is preferred (see disk(7)). The header file <sys/scsi.h> has useful information for SCSI devices. The following is included from <sys/scsi.h>: #define SIOC_INQUIRY _IOR('S', 2, union inquiry_data) #define SIOC_CAPACITY _IOR('S', 3, struct capacity) /* SCSI-1 inquiry structure */ struct inquiry { unsigned char dev_type; unsigned int rmb:1; unsigned int dtq:7; unsigned int iso:2; unsigned int ecma:3; unsigned int ansi:3; unsigned int resv:4; unsigned int rdf:4; unsigned char added_len; unsigned char dev_class[3]; char vendor_id[8]; char product_id[16]; char rev_num[4]; unsigned char vendor_spec[20]; unsigned char resv4[40]; unsigned char vendor_parm_bytes[32]; }; /* SCSI-2 inquiry structure */ struct inquiry_2 { unsigned int periph_qualifier:3; unsigned int dev_type:5; unsigned int rmb:1; unsigned int dtq:7; unsigned int iso:2; unsigned int ecma:3; unsigned int ansi:3; unsigned int aenc:1; unsigned int trmiop:1; unsigned int resv1:2; unsigned int rdf:4; unsigned char added_len; unsigned char resv2[2]; unsigned int reladr:1; unsigned int wbus32:1; unsigned int wbus16:1; unsigned int sync:1; unsigned int linked:1; unsigned int resv3:1; unsigned int cmdque:1; unsigned int sftre:1; char vendor_id[8]; char product_id[16]; char rev_num[4]; unsigned char vendor_spec[20]; unsigned char resv4[40]; unsigned char vendor_parm_bytes[32]; }; /* union for SIOC_INQUIRY ioctl */ union inquiry_data { struct inquiry inq1; /* SCSI-1 inquiry */ struct inquiry_2 inq2; /* SCSI-2 inquiry */ }; /* structure for SIOC_CAPACITY ioctl */ struct capacity { int lba; int blksz; }; The SIOC_XSENSE ioctl returns detailed information about device status and errors when such information is available. Since there have been multiple versions of the SCSI standard for sense (status) data, multiple versions of the sense data declaration are provided. The SCSI-1 and non-aligned versions are provided for backward compatibility only. If no new CHECK-CONDITION-caused REQUEST SENSE command data has been obtained since the last SIOC_XSENSE ioctl call, the xsense_aligned.error_class and sense_2_aligned.error_code fields will contain the value zero. Applications which require more accurate REQUEST SENSE data handling should use the SCSI device-control driver (see scsi_ctl(7)). The following information is included from <sys/scsi.h>: #define SIOC_XSENSE _IOR('S', 7, union sense_data) /* structure for SIOC_XSENSE ioctl */ union sense_data { struct xsense_aligned r_sense1a; /* SCSI and CCS devices */ struct sense_2_aligned r_sense2a; /* SCSI-2 devices */ }; /* structure for SCSI-1 and SCSI-CCS sense data */ struct xsense_aligned { unsigned int valid:1; unsigned int error_class:3; unsigned int error_code:4; unsigned char seg_num; unsigned int parms:4; unsigned int sense_key:4; unsigned char lba[4]; unsigned char add_len; unsigned char copysearch[4]; unsigned char sense_code; unsigned char resv; unsigned char fru; unsigned char field; unsigned char field_ptr[2]; unsigned char dev_error[4]; unsigned char misc_bytes[106]; }; /* structure for SCSI-2 sense data */ struct sense_2_aligned { unsigned int info_valid:1; unsigned int error_code:7; unsigned char seg_num; unsigned int filemark:1; unsigned int eom:1; unsigned int ili:1; unsigned int resv:1; unsigned int key:4; unsigned char info[4]; unsigned char add_len; unsigned char cmd_info[4]; unsigned char code; unsigned char qualifier; unsigned char fru; unsigned char key_specific[3]; unsigned char add_sense_bytes[113]; }; ERRORSThe following errors may result from a call to a SCSI device driver:
Manual entries that describe specific SCSI peripheral device drivers may provide additional qualification of error results. WARNINGSUse of devices that are not officially supported can cause data loss, system panics and device damage. HP-UX device drivers expect devices to be SCSI-2 compliant. Unsupported devices that are only SCSI-CCS compliant may work but their use is discouraged. Use of unsupported devices that are only SCSI-1 compliant is strongly discouraged. Changing SCSI bus connectivity (recabling) while the system is running is not supported. Switching SCSI device power on or off while the device is connected to a system that does not support powerfail recovery is not supported. These activities are known to cause data loss and system panics. On systems that support the scsi_ctl interface, the SIOC_CMD_MODE, SIOC_SET_CMD, and SIOC_RETURN_STATUS ioctls are obsolete (see scsi_ctl(7)). Direct manipulation of SCSI devices via the scsi_ctl interface provides a more functionally complete and easier-to-use means of low level SCSI device control (see scsi_ctl(7)). Drivers that support only devices which have no meaningful size may not support the SIOC_CAPACITY ioctl. Total device size in bytes may exceed 232-1 for some devices. DEPENDENCIESsdisk/schgr/sflop/stapeThe SIOC_EXCLUSIVE ioctl may be used to obtain and release exclusive access. Exclusive access, which prevents simultaneous access by other applications, is required for some operations and may be desirable in other circumstances. The following exclusive access control arguments are supported:
The SIOC_MEDIUM_CHANGED ioctl indicates when the media in a removable-media device may have changed. A value of ``1'' indicates the device media may have changed since the last SIOC_MEDIUM_CHANGED ioctl call. Note that only the first such call after a media change receives this indication. This means that media changes are likely to be missed if multiple applications are attempting to detect media changes. Exclusive access, obtained through use of the SIOC_EXCLUSIVE ioctl, can be used to avoid this problem. The following information is included from <sys/scsi.h>: #define SIOC_MEDIUM_CHANGED _IOR('S', 42, int) #define SIOC_EXCLUSIVE _IOR('S', 68, int) disc3The SIOC_VPD_INQUIRY ioctl allows access to detailed device specific information. The page_code field specifies which SCSI vital product data page is requested. The page_buf field is filled with the requested page data. The following information is included from <sys/scsi.h>: #define SIOC_VPD_INQUIRY _IOWR('S', 10, struct vpd_inquiry) /* union for SIOC_VPD_INQUIRY ioctl */ struct vpd_inquiry { char page_code; /* VPD page code */ char page_buf[126]; /* buffer for VPD page info */ }; |
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