Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
65
17.4.4
SAS Speed Negotiation
The drive supports G1 (1.5 Gbps), G2 (3.0 Gbps), G3 (6.0 Gbps), and G4 (12.0 Gbps) negotiation speeds. The
default maximum negotiation rate is G4 speed (per byte 32 in the PHY Control and Discover Mode Page 19 subpage
1). Drive is SAS3 device and supports SNW-1, SNW-2, SNW-3 speed negotiation with PHY capabilities exchange,
and both transmitter training (Train_Tx-SNW, at 12G only) and receiver training (Train_Rx-SNW or Train-SNW). The
drive’s PHY capabilities are defined in table below:
PHY Capabilities:
Table 30 SAS Speed Negotiation
Byte /Bit
7
6
5
4
3
2
1
0
0
Start =1b
TX SSC
Type = 0b
Reserved Requested Logical Link Rate = 0h
1
G1 Without
SSC=1b
G1 With
SSC=1b
G2 Without
SSC=1b
G2 With
SSC=1b
G3 Without
SSC=1b
G3 With
SSC=1b
G4
Without
SSC=1b
G4 With
SSC=1b
2
Reserved
3
Reserved Parity
 Start is set to 1 to indicate the beginning of the PHY capabilities
 TX SSC Type is set to 1 to indicate that PHY’s transmitter uses center-spreading-SCC when SSC is enabled
 TX SSC Type is set to 0 to indicate that PHY’s transmitter uses down-spreading-SSC when SSC is enabled
 Requested Logical Link Rate field is set to 0 to indicate that drive does not support multiplexing
 G1 Without SSC is set to 1 to indicate that drive supports G1 (1.5 Gbps) without SSC
 G2 Without SSC is set to 1 to indicate that drive supports G2 (3.0 Gbps) without SSC
 G3 Without SSC is set to 1 to indicate that drive supports G3 (6.0 Gbps) without SSC
 G4 Without SSC is set to 1 to indicate that drive supports G4 (12.0 Gbps) without SSC
 G1 With SSC set to 1 to indicate that drive supports G1 (1.5 Gbps) with SSC
 G2 With SSC set to 1 to indicate that drive supports G2 (3.0 Gbps) with SSC
 G3 With SSC set to 1 to indicate that drive supports G3 (6.0 Gbps) with SSC
 G4 With SSC is set to 1 to indicate that drive supports G4 (12.0 Gbps) with SSC
 Parity is set to 1 for even parity of the total number of SNW-3 PHY capabilities, including Start bit.
Training is based on the highest untried commonly supported settings on the exchanged SNW-3 supported settings
bits. If a Train-SNW is invalid and there are additional, untried, commonly supported settings exchanged during
SNW-3, then a new Train-SNW will be performed based on the next highest untried, commonly supported settings.
Table 30 defines the priority of the supported settings bits.
Table 31 Supported Settings Bit Priorities
Priority
Bit
Highest
G4 With SSC bit
...
G4 Without SSC bit
...
G3 With SSC bit
...
G3 Without SSC bit
...
G2 With SSC bit
…
G2 Without SSC bit