HGST HUS724040ALS640 User Manual

HGST Ultrastar 7K4000 (SAS) Hard Disk Drive Specification
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17.5.4 SAS Speed Negotiation
The Drive supports G1 (1.5 Gbps), G2 (3.0 Gbps), and G3 (6.0 Gbps) negotiation speeds. The default maximum negotiation
rate is G3 speed (per byte 32 in the Phy Control and Discover Mode Page 19 subpage 1). Drive is SAS2 device and supports
SNW-1, SNW-2, and SNW-3 speed negotiation with Phy capabilities exchange, and training (Train-SNW). Phy capabilities is
defined in table below:
Phy Capabilities:
• Start bit is 1 to indicate the beginning of the Phy capabilities
• TX SSC Type bit is set to 0 to indicate that Phy’s transmitter uses down spreading SCC when is enabled (e.g.
the phy is a SAS phy).
• Request Logical Link Rate field is 0 to indicate that drive does not support multiplexing
• G1 Without SSC bit set to 1 indicates that drive supports G1(1.5 Gbps) without SSC
• G2 Without SSC bit set to 1 indicates that drive supports G2(3.0 Gbps) without SSC
• G3 Without SSC bit set to 1 indicates that drive supports G3(6.0 Gbps) without SSC
• G1 With SSC bit set to 1 indicates that drive supports G1(1.5 Gbps) with SSC
• G2 With SSC bit set to 1 indicates that drive supports G2(3.0 Gbps) with SSC
• G3 With SSC bit set to 1 indicates that drive supports G3(6.0 Gbps) with SSC
• Parity bit 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 26 defines the priority of
the supported settings bits.
Table 26: Supported Settings Bit Priorities
Byte /Bit 7 6 5 4 3 2 1 0
0 St a r t = 1 b T X S S C
Type = 0b
Reserved
Requested Logical Link Rate = 0h
1 G1 Without
SSC=1b
G1 With
SSC=0b
G2 Without
SSC=1b
G2 With
SSC=0b
G3 Without
SSC=1b
G3 With
SSC=0b
Reserved
2
Reserved
3
Reserved
Parity
Priority Bit
Highest G3 With SSC bit
... G3 Without SSC bit
... G2 With SSC bit
... G2 Without SSC bit
... G1 With SSC bit
Lowest G3 Without SSC bit

HGST HUS724040ALS640 Specifications

General

Brand	HGST
Model	HUS724040ALS640
Category	Storage
Language	English