Hitachi ULTRASTAR 15K450 HUS154530VLF400 - Manual (Page 72)

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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• LPEfx Loop Port Enable all
• LIP(F7,F7) Loop Initialization, no valid AL_PA
• LIP(F8,F7) Loop Initialization, loop failure, no valid AL_PA
• LIP(F7,AL_PS) Loop Initialization, valid AL_PA
• LIP(F8,AL_PS) Loop Initialization, loop failure, valid AL_PA
• LIP(AL_PD,AL_PS) Loop Initialization, reset L_Port
17.1.4 Frames
Information transfer is achieved via frames that are constructed from words and ordered sets. All frames have the same general
format, as shown in Table 26.
Table 26: General frame format
The SOF ordered set indicates the start of frame and provides word synchronization.
The Header is the first field after the SOF delimiter. It is used by the link control facility to control link operations, control
device protocol transfer, and to detect missing or out of order frames. The header is illustrated in Table 27.
FC-PH describes the content of each field except 'Parameter'. SCSI-FCP defines this field as RLTV_OFF (Relative Offset).
Table 27: Frame header
The Payload follows the header and has a length between 0 and 2048 bytes, which must be divisible by 4. An additional 0-3
fill bytes are appended to the payload in order to ensure that it ends on a word boundary.
The Cyclic Redundancy Check (CRC) is a four byte field following the payload. It is used to verify the integrity of the header
and payload.
The EOF ordered set marks the end of a frame.
17.1.5 Sequences
A Sequence is a set of one or more related frames that flow in one direction only. The sequence is identified by the Sequence
Identifier (SEQ_ID) field in the frame header.
Field name SOF Header Payload Fill bytes CRC EOF
Field size, # of bytes 4 24 0 to 2048 0 to 3 4 4
Byte
word
3 2 1 0
0 R-CTL D-ID
1 Reserved S-ID
2 TYPE F-CTL
3 SEQ-ID DF-CTL SEQ-CNT
4 OX-ID RX-ID
5 Parameter (RLTV_OFF)