Fujitsu MPA3035AT Product Manual - Page 167

Empty data, Mis-hit data, Requested data, Empty, ahead

Get Fujitsu MPA3035AT - Desktop 3.5 GB Hard Drive PDF manuals and user guides View all Fujitsu MPA3035AT manuals
Add to My Manuals
Save this manual to your list of manuals

Page 167 highlights

(3) Sequential read When the disk drive receives the read command that targets the sequential address to the previous read command, the disk drive starts the read-ahead operation. a. Sequential command just after non-sequential command When the previously executed read command is an non-sequential command and the last sector address of the previous read command is sequential to the lead sector address of the received read command, the disk drive assumes the received command is a sequential command and performs the read-ahead operation after reading the requested data. 1) At receiving the sequential read command, the disk drive sets the DAP and HAP to the sequential address of the last read command and reads the requested data. HAP Mis-hit data Empty data DAP 2) The disk drive transfers the requested data that is already read to the host system with reading the requested data. HAP Mis-hit data Requested data Empty data DAP 3) After completion of the reading and transferring the requested data to the host system, the disk drive performs the read-ahead operation continuously. HAP Mis-hit data Requested data Readahead Empty data data DAP C141-E034-02EN 6 - 17

  • 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
C141-E034-02EN
6 - 17
(3)
Sequential read
When the disk drive receives the read command that targets the sequential address to the previous
read command, the disk drive starts the read-ahead operation.
a.
Sequential command just after non-sequential command
When the previously executed read command is an non-sequential command and the last sector
address of the previous read command is sequential to the lead sector address of the received
read command, the disk drive assumes the received command is a sequential command and
performs the read-ahead operation after reading the requested data.
1)
At receiving the sequential read command, the disk drive sets the DAP and HAP to the
sequential address of the last read command and reads the requested data.
Empty data
Mis-hit data
2)
The disk drive transfers the requested data that is already read to the host system with
reading the requested data.
Requested data
DAP
HAP
Mis-hit data
Empty data
3)
After completion of the reading and transferring the requested data to the host system, the
disk drive performs the read-ahead operation continuously.
Mis-hit data
Requested data
DAP
HAP
Empty
data
Read-
ahead
data
DAP
HAP