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# SCSITaggedTaskIdentifier

64-bit number to represent a unique task identifier.

```
typedef UInt64 SCSITaggedTaskIdentifier;
```

## Discussion

The Tagged Task Identifier is used when a Task has a Task Attribute other than SIMPLE. The SCSI Application Layer client that controls the Logical Unit for which a Task is intended is required to guarantee that the Task Tag Identifier is unique. Zero cannot be used a a Tag value as this is used to when a Tagged Task Identifier value is needed for a Task with a SIMPLE attribute.

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