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Hitachi 7K100 Hard Drive Specifications - Page 97

Seek Overlap, Write Cache function

UPC - 683728198671

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11.12 Seek Overlap The drive provides accurate seek time measurement method. The seek command is usually used to measure the device seek time by accumulating execution time for a number of seek commands. With typical implementation of the seek command, this measurement must include the device and host command overhead. To eliminate this overhead, the drive overlaps the seek command as described below. The first seek command completes before the actual seek operation is over. The device can then receive the next seek command from the host. However, the actual seek operation for the next seek command starts right after completion of the actual seek operation for the first seek command. In other words, the execution of two seek commands overlaps excluding the actual seek operation. With this overlap, total elapsed time for a number of seek commands is the total accumulated time for the actual seek operation plus one pre- and post-overhead. When the number of seeks is large, this overhead can be ignored. (1) With overlap Host process Device process Seek operation Overhead A B Total time = (n-1) * (Seek operation) + A + B (2) Without overlap Host process Device process Seek operation Overhead A B+A B+A B Total time = n * (Seek operation + A + B) Figure 7: Seek overlap 11.13 Write Cache function Write cache is a performance enhancement whereby the device reports completion of the write command (Write Sector(s) and Write Multiple) to the host as soon as the device has received all of the data in its buffer. The device assumes responsibility to write the data subsequently onto the disk. • Writing data after completed acknowledgment of a write command, soft reset, or hard reset does not affect its operation but power off terminates writing operation immediately and unwritten data is lost. • Flush cache, Soft reset, Standby, Standby Immediate, and Sleep are executed after the completion of writing to disk media on enabling write cache function. The host system can confirm the completion of Write Cache operation by issuing Flush Cache command, Soft reset, Standby command, Standby Immediate command, or Sleep command, and then confirming the completion of the issued command. Travelstar 7K100 Hard Disk Drive Specification 83

Section	Page
1.0 General	15
1.1 Introduction	15
1.2 References	15
1.3 Abbreviations	15
1.4 Caution	17
1.5 Drive handling precautions	17
2.0 Outline of the drive	19
3.0 Fixed-disk subsystem description	23
3.1 Control electronics	23
3.2 Head disk assembly data	23
4.0 Drive characteristics	25
4.1 Formatted capacity	25
4.2 Data sheet	25
4.3 Cylinder allocation	26
4.4 Performance characteristics	27
4.4.1 Command overhead	27
4.4.2 Mechanical positioning	28
4.4.3 Operating modes	30
5.0 Data integrity	31
5.1 Data loss at power off	31
5.2 Write Cache	31
5.3 Equipment status	31
5.4 WRITE safety	32
5.5 Data buffer test	32
5.6 Error recovery	32
5.7 Automatic reallocation	32
5.8 ECC	33
6.0 Specification	35
6.1 Environment	35
6.1.1 Temperature and humidity	35
6.1.2 Radiation noise	37
6.1.3 Conductive noise	37
6.1.4 Magnetic fields	37
6.2 DC power requirements	38
6.2.1 Power consumption efficiency	38
6.3 Reliability	39
6.3.1 Data Reliability	39
6.3.2 Failure prediction (S.M.A.R.T.)	39
6.3.3 Cable noise interference	39
6.3.4 Service life and usage condition	39
6.3.5 Preventive maintenance	39
6.3.6 Load/unload	40
6.4 Mechanical specifications	42
6.4.1 Physical dimensions and weight	42
6.4.2 Mounting hole locations	42
6.4.3 Connector and jumper description	42
6.4.4 Mounting orientation	43
6.4.5 Load/unload mechanism	43
6.5 Vibration and shock	44
6.5.1 Operating vibration	44
6.5.2 Nonoperating vibration	45
6.5.3 Operating shock	45
6.5.4 Nonoperating shock	45
6.6 Acoustics	46
6.6.1 Sound power levels	46
6.6.2 Discrete tone penalty	46
6.7 Identification labels	47
6.8 Electromagnetic compatibility	47
6.8.1 CE mark	47
6.8.2 C-TICK mark	47
6.8.3 BSMI mark	47
6.8.4 MIC mark	47
6.9 Safety	48
6.9.1 UL and CSA approval	48
6.9.2 IEC compliance	48
6.9.3 German safety mark	48
6.9.4 Flammability	48
6.9.5 Secondary circuit protection	48
6.10 Packaging	48
7.0 Electrical interface specification	49
7.1 Cabling	49
7.2 Interface connector	49
7.3 Signal definitions	50
7.4 Signal descriptions	51
7.5 Interface logic signal levels	54
7.6 Reset timings	54
7.7 PIO timings	55
7.8 Multi word DMA timings	56
7.9 Ultra DMA timings	57
7.9.1 Initiating Read DMA	57
7.9.2 Host Pausing Read DMA	58
7.9.3 Host Terminating Read DMA	59
7.9.4 Device Terminating Read DMA	60
7.9.5 Initiating Write DMA	61
7.9.6 Device Pausing Write DMA	62
7.9.7 Device Terminating Write DMA	63
7.9.8 Host Terminating Write DMA	64
7.10 Drive address setting	65
7.11 Addressing of HDD registers	66
8.0 General	69
8.1 Introduction	69
8.2 Terminology	69
9.0 Deviations from standard	71
10.0 Register	73
10.1 Alternate Status Register	74
10.2 Command Register	74
10.3 Data Register	74
10.4 Device Control Register	75
10.5 Drive Address Register	75
10.6 Device Register	76
10.7 Error Register	76
10.8 Features Register	77
10.9 LBA High Register	77
10.10 LBA Low Register	77
10.11 LBA Mid Register	77
10.12 Sector Count Register	77
10.13 Status Register	78
11.0 General	79
11.1 Reset response	79
11.2 Register initialization	80
11.3 Diagnostic and Reset considerations	81
11.4 Power-off considerations	82
11.4.1 Load/Unload	82
11.4.2 Emergency unload	82
11.4.3 Required power-off sequence	82
11.5 Sector Addressing Mode	83
11.5.1 Logical CHS addressing mode	83
11.5.2 LBA addressing mode	83
11.6 Power management features	84
11.6.1 Power mode	84
11.6.2 Power management commands	84
11.6.3 Standby/Sleep command completion time	84
11.6.4 Standby timer	85
11.6.5 Status	85
11.6.6 Interface capability for power modes	85
11.6.7 Initial Power Mode at Power On	85
11.7 Advanced Power Management (ABLE-3) feature	85
11.7.1 Performance Idle Mode	86
11.7.2 Active Idle Mode	86
11.7.3 Low Power Idle Mode	86
11.7.4 Transition time	86
11.8 S.M.A.R.T. Function	87
11.8.1 Attributes	87
11.8.2 Attribute values	87
11.8.3 Attribute thresholds	87
11.8.4 Threshold exceeded condition	87
11.8.5 S.M.A.R.T. commands	87
11.8.6 S.M.A.R.T. operation with power management modes	88
11.9 Security Mode Feature Set	88
11.9.1 Security mode	88
11.9.2 Security level	88
11.9.3 Password	89
11.9.4 Master Password Revision Code	89
11.9.5 Command table	92
11.10 Protected Area Function	93
11.10.1 Example for operation (In LBA Mode)	93
11.10.2 Set Max security extension commands	94
11.11 Address Offset Feature (vendor specific)	95
11.11.1 Enable/Disable Address Offset Mode	95
11.11.2 Identify Device Data	96
11.11.3 Exceptions in Address Offset Mode	96
11.12 Seek Overlap	97
11.13 Write Cache function	97
11.14 Reassign Function	98
11.14.1 Auto Reassign Function	98
11.15 48-bit Address Feature Set	99
12.0 Command protocol	101
12.1 Data In commands	101
12.2 Data Out Commands	102
12.3 Non-data commands	103
12.4 DMA Data Transfer commands:	105
13.0 Command descriptions	107
13.1 Check Power Mode (E5h/98h)	112
13.2 Device Configuration Overlay (B1h)	113
13.2.1 DEVICE CONFIGURATION RESTORE (subcommand C0h)	113
13.2.2 DEVICE CONFIGURATION FREEZE LOCK (subcommand C1h)	113
13.2.3 DEVICE CONFIGURATION IDENTIFY (subcommand C2h)	114
13.2.4 DEVICE CONFIGURATION SET (subcommand C3h)	114
13.3 Execute Device Diagnostic (90h)	116
13.4 Flush Cache (E7h)	117
13.5 Flush Cache EXT (EAh)	118
13.6 Format Track (50h: vendor specific)	119
13.7 Format Unit (F7h: vendor specific)	120
13.8 Identify Device (ECh)	121
13.9 Idle (E3h/97h)	130
13.10 Idle Immediate (E1h/95h)	131
13.11 Initialize Device Parameters (91h)	132
13.12 Read Buffer (E4h)	133
13.13 Read DMA (C8h/C9h)	134
13.14 Read DMA EXT (25h)	136
13.15 Read Log Ext (2Fh)	138
13.15.1 General Purpose Log Directory	139
13.15.2 Extended Comprehensive SMART Error Log	140
13.15.3 Extended Self-test log sector	142
13.16 Read Long (22h/23h)	144
13.17 Read Multiple (C4h)	146
13.18 Read Multiple EXT (29h)	148
13.19 Read Native Max ADDRESS (F8h)	149
13.20 Read Native Max ADDRESS EXT (27h)	150
13.21 Read Sectors (20h/21h)	151
13.22 Read Sector(s) EXT (24h)	152
13.23 Read Verify Sectors (40h/41h)	154
13.24 Ready Verify Sector(s) EXT (42h)	156
13.25 Recalibrate (1xh)	158
13.26 Security Disable Password (F6h)	159
13.27 Security Erase Prepare (F3h)	160
13.28 Security Erase Unit (F4h)	161
13.29 Security Freeze Lock (F5h)	163
13.30 Security Set Password (F1h)	164
13.31 Security Unlock (F2h)	166
13.32 Seek (7xh)	167
13.33 Sense Condition (F0h: vendor specific)	168
13.34 Set Features (EFh)	169
13.35 Set Max ADDRESS (F9h)	171
13.36 Set Max ADDRESS EXT (37h)	173
13.37 Set Multiple (C6h)	175
13.38 Sleep (E6h/99h)	176
13.39 S.M.A.R.T. Function Set (B0h)	177
13.39.1 S.M.A.R.T. Function Subcommands	178
13.39.2 Device Attribute Data Structure	183
13.39.3 Device Attribute Thresholds data structure	188
13.39.4 S.M.A.R.T. Log Directory	190
13.39.5 S.M.A.R.T. error log sector	190
13.39.6 Self-test log data structure	193
13.39.7 Selective self-test log data structure	193
13.39.8 Error reporting	194
13.40 Standby (E2h/96h)	195
13.41 Standby Immediate (E0h/94h)	196
13.42 Write Buffer (E8h)	197
13.43 Write DMA (CAh/CBh)	198
13.44 Write DMA EXT (35h)	200
13.45 Write Log Ext (3Fh)	202
13.46 Write Long (32h/33h)	203
13.47 Write Multiple (C5h)	205
13.48 Write Multiple EXT (39h)	206
13.49 Write Sectors (30h/31h)	208
13.50 Write Sectors(s) EXT (34h)	210
13.51 Write Verify (3Ch: vendor specific)	211
14.0 Time-out values	213
15.0 Appendix	215
15.1 Commands Support Coverage	215
15.2 SET FEATURES Commands Support Coverage	217

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Travelstar 7K100 Hard Disk Drive Specification

11.12

Seek Overlap

The drive provides accurate seek time measurement method. The seek command is usually used to measure the

device seek time by accumulating execution time for a number of seek commands. With typical implementation of

the seek command, this measurement must include the device and host command overhead. To eliminate this

overhead, the drive overlaps the seek command as described below.

The first seek command completes before the actual seek operation is over. The device can then receive the next

seek command from the host. However, the actual seek operation for the next seek command starts right after

completion of the actual seek operation for the first seek command. In other words, the execution of two seek

commands overlaps excluding the actual seek operation.

With this overlap, total elapsed time for a number of seek commands is the total accumulated time for the actual

seek operation plus one pre- and post-overhead. When the number of seeks is large, this overhead can be ignored.

Figure 7: Seek overlap

11.13

Write Cache function

Write cache is a performance enhancement whereby the device reports completion of the write command (Write

Sector(s) and Write Multiple) to the host as soon as the device has received all of the data in its buffer. The device

assumes responsibility to write the data subsequently onto the disk.

•

Writing data after completed acknowledgment of a write command, soft reset, or hard reset

does not affect its operation but power off terminates writing operation immediately and

unwritten data is lost.

•

Flush cache, Soft reset, Standby, Standby Immediate, and Sleep are executed after the comple-

tion of writing to disk media on enabling write cache function. The host system can confirm

the completion of Write Cache operation by issuing Flush Cache command, Soft reset, Standby

command, Standby Immediate command, or Sleep command, and then confirming the comple-

tion of the issued command.

(1) With overlap

(2) Without overlap

Host process

Device process

Seek operation

Overhead

B+A

Total time = (n-1) * (Seek operation) + A + B

Total time = n * (Seek operation + A + B)