HP-UX Reference (11i v2 04/09) - 7 Device (Special) Files, 9 General Information, Index (vol 10)

a
autochanger(7) autochanger(7)
repositions two different units of media. One unit of media is moved from the element specified by
the source field to the element specified by the
first_destination
field. A second unit of
media is moved from the element specified by the
first_destination
field to the element
specified by the
second_destination
field. In an autochanger with multiple changer mechan-
isms, or a media staging area, an exchange occurs if the
source and second_destination
fields are the same.
DEPENDENCIES
To obtain access to disk surfaces within HP magneto-optical libraries, the ssrfc module must be specified
in the system configuration file. The ssrfc module depends on either the schgr driver, or the autox0
driver. If ssrfc is to be included, then one or both of schgr or autox0 must also be included.
DEFAULT CONFIGURATIONS
By default,
ssrfc, schgr, and autox0
are not included in the system configuration
(
/stand/system
) file.
EXAMPLES
The following example uses the
SIOC_ELEMENT_ADDRESSES
and SIOC_ELEMENT_STATUS ioctl
functions to get bus address information about the drives in an HP magneto-optical autochanger:
int last_drive_el;
struct element_addresses el_addrs;
struct element_status el_stat;
/*
* Changer attached to card instance 1, with SCSI target id 5, lun 0.
*/
fd = open("/dev/rac/c1t5d0",O_RDWR);
if ((error = ioctl(fd, SIOC_ELEMENT_ADDRESSES, &el_addrs)) != 0) {
syserr("ioctl: SIOC_ELEMENT_ADDRESSES");
return -1;
} else {
last_drive_el = el_addrs.first_data_transfer
+ el_addrs.num_data_transfers - 1;
for (i = el_addrs.first_data_transfer; i <= last_drive_el; i++) {
el_stat.element = i;
if ((error = ioctl(fd, SIOC_ELEMENT_STATUS, &el_stat)) != 0) {
syserr("ioctl: SIOC_ELEMENT_ADDRESSES");
return -1;
} else {
/*
* You may wish to also check some of the other fields
* in the el_stat structure to verify that the data is
* valid. Fields: el_stat.access (ac accessible),
* el_stat.except (exception).
*/
if (! el_stat.not_bus && el_stat.id_valid) {
drive[i].addr = el_stat.bus_address;
if (! el_stat.lu_valid) {
drive[i].lun = 0;
} else {
drive[i].lun = el_stat.lun;
}
}
}
}
}
WARNINGS
Do not use LVM to configure multiple autochanger surfaces as one large file system. LVM was designed
for on-line volumes. In an autochanger, only the disks actualy in the drives are on-line, while the disks
stored in their slots are off-line. If LVM is not carefully configured, thrashing of the autochanger disks
result in undesirable I/O performance. Plan carefully for best performance.
HP-UX 11i Version 2: September 2004 − 6 − Hewlett-Packard Company Section 7−−9