scsi(7) scsi(7)
NAME [Toc] [Back]
scsi - Small Computer System Interface device drivers
DESCRIPTION [Toc] [Back]
The 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-3'') 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 for very
large devices, the ioctl argument can overflow, SIOC_STORAGE_CAPACITY
is a better choice, than SIOC_CAPACITY where devices can be large.
Also 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)
#define SIOC_STORAGE_CAPACITY _IOR('S', 101, storage_capacity_t)
/* 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;
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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 {
uint32_t lba;
uint32_t blksz;
};
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/* structure for SIOC_STORAGE_CAPACITY ioctl */
typedef struct {
uint64_t lba;
uint32_t blksz;
} storage_capacity_t;
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;
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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];
};
ERRORS [Toc] [Back]
The following errors may result from a call to a SCSI device driver:
[EACCES] Required permission is denied for the the device
or operation.
[ENXIO] If resulting from an open call, this indicates
there is no device at the specified address. For
other calls, this indicates the specified address
is out of range or the device may no longer be
accessed.
[EINVAL] If resulting from an open call, this indicates the
device is not supported by the device driver (e.g.
incorrect device type). For other calls, this
indicates the request or some request argument is
invalid. If resulting from the SIOC_CAPACITY
ioctl, one or more of the fields in the argument
structure may have overflowed.
[EBUSY] This indicates the device is not ready for use or
that the requested operation conflicts with other
operations (e.g. the device is currently open via
another device driver or exclusive access is in
effect).
[EIO] Indicates a SCSI protocol or communication problem
has occurred, or that a SCSI command resulted in a
non-good status.
Manual entries that describe specific SCSI peripheral device drivers
may provide additional qualification of error results.
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WARNINGS [Toc] [Back]
Use 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 2**32-1 for some devices.
DEPENDENCIES [Toc] [Back]
sdisk/schgr/sflop/stape
The 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:
0 Release exclusive access to logical unit (LUN).
1 Gain exclusive access to logical unit (LUN).
2 Release exclusive access to associated SCSI target.
3 Gain exclusive access to associated SCSI target.
4 Release exclusive access to associated SCSI bus.
5 Gain exclusive access to associated SCSI bus.
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.
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The following information is included from <sys/scsi.h>:
#define SIOC_MEDIUM_CHANGED _IOR('S', 42, int)
#define SIOC_EXCLUSIVE _IOR('S', 68, int)
scsi_disk
The 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 */
};
FILES [Toc] [Back]
/usr/include/sys/scsi.h
SEE ALSO [Toc] [Back]
diskinfo(1M), ioctl(2) autochanger(7), scsi_ctl(7), scsi_disk(7),
scsi_tape(7).
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