SET_ACTIVE_PARTITION

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The SET_ACTIVE_PARTITION IOCTL is used to position the tape to a specific partition. Then, it becomes the current active partition for subsequent commands and a specific logical bock id in the partition. To position to the beginning of the partition, the logical_block_id field is set to 0.

The data structure that is used with this IOCTL is

struct set_active_partition {
  uchar partition_number;          /* Partition number 0-n to change to     */
  ullong logical_block_id;         /* Blockid to locate to within partition */
  char reserved[32];
  };

Examples of the SET_ACTIVE_PARTITION IOCTL

#include <sys/Atape.h>

  struct set_active_partition partition;

  /* position the tape to partition 1 and logical block id 12 */
  partition.partition_number = 1;
  partition.logical_block_id = 12;
  ioctl(fd, SET_ACTIVE_PARTITION, &partition);

  /* position the tape to the beginning of partition 0 */
  partition.partition_number = 0;
  partition.logical_block_id = 0;
  ioctl(fd, SET_ACTIVE_PARTITION, &partition);