Hitachi HUS154530VLF400 User Manual

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification

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Capability Entry(s) are used to specify standards and profiles, with which a node is compliant or supports. Nodes may also use 
capability entries to exchange vendor unique parameters or information.

The Flags field is as follows:

 This flag is only meaningful when the RNC Flags Select bit is set to one. Furthermore, it may only be set in the first 
Capability Entry in the RNC Payload. When the RNC Flags Select field and the Invalidate Previous field are both set 
to one, then the node issuing the RNC is requesting that the responding node invalidate this Capability Entry. All 
bytes of the Capability Entry marked with the Invalidate flag must match the values set in a prior RNC exchange. 
When the Invalidate Previous field is reset(0), the responding node selects one Capability Entry to return in the 
RNC_ACC.

 Since the drive does not support the Select Flag (it must be set to 0), the Invalidate Previous Flag has no meaning and 
is ignored.   

 When this flag is set to zero, the Capability Entry shall be exactly 4 bytes long. If this flag is set to one, the length of 
the Capability Entry is 4 bytes plus the length of the Extension.

• 0 0  Specifies that the Document Identifier field should be interpreted according to Table 66. 

• 0 1  Specifies a Vendor Unique Document Identifier.

• 1 0  Specifies a Vendor Unique Document Identifier as defined by the vendor of the N_Port receiving 

the RNC payload. 

• 1 1  Reserved

Preference is a two bit value that indicates the level of support or performance relative to the other capabilities sup-
ported by the node. It is used to aid a node in selecting a specific capability when multiple capabilities are supported. 
The Preference field has a range from 0 to 3.

Flags

1

Document Identifier

1

Low Revision

1

High Revision

1

Reserved

0 or 2

Extension Length

0 or 2

Extension

0 or n