Hitachi 7K320 Specifications - Page 65

Seek Overlap, Write Cache Function

Get Hitachi 7K320 - Travelstar Mobile Hard Drive PDF manuals and user guides
UPC - 890552647200
View all Hitachi 7K320 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 65 highlights

7K320 SATA OEM Specification Figure 8 Set Max security mode transition 12.11 Seek Overlap HTS7232XXL9SAXX / HTS7232XXL9A3XX provide 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 including the device and host command overhead. To eliminate this overhead, HTS7232XXL9SAXX / HTS7232XXL9A3XX overlap the seek command as described below. The first seek command completes before the actual seek operation is over. Then device can receive the next seek command from the host but actual seek operation for the next seek command starts right after the actual seek operation for the first seek command is completed. 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, just this one overhead can be ignored. Figure 9 Seek overlap 12.12 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 Page 65 of 176

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
7K320 SATA OEM Specification
Page 65 of 176
Figure 8 Set Max security mode transition
12.11
Seek Overlap
HTS7232XXL9SAXX / HTS7232XXL9A3XX provide 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
including
the
device
and
host
command
overhead.
To
eliminate
this
overhead,
HTS7232XXL9SAXX / HTS7232XXL9A3XX overlap the seek command as described below.
The first seek command completes before the actual seek operation is over. Then device can receive
the next seek command from the host but actual seek operation for the next seek command starts
right after the actual seek operation for the first seek command is completed. 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, just
this one overhead can be ignored.
Figure 9 Seek overlap
12.12
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