Streaming Performance Log; Table 109 Streaming Performance Parameters Log; Table 110 Sector Time Array Entry (Linearly Interpolated); Table 111 Position Array Entry (Linearly Interpolated) - Hitachi HDS723020BLA642 Specifications

11.18.8 Streaming Performance log

Table 109 defines the format of the log returned by the Read Log Ext command, when the LBA Low register is
20h. This data set is referred to as the Streaming Performance Parameters log, the length of which (in sectors)
is statically indicated in Read Log Ext log address 00h (Log Directory).
The host should base its calculations on the larger of its Typical Host Interface Sector Time and the device
reported Sector Time values, and on the sum of the device reported Access Time values and any additional
latency that only the host is aware of (e.g. host command overhead, etc.).
Description
Stream Performance Parameters log version
K, Number of Regions in Sector Time Array
L, Number of Positions in Position Array
M, Number of Position-differences in Access T
Sector Time Array
Position Array
Access Time Array
Reserved

Table 109 Streaming Performance Parameters log

Description
LBA of reference location (LBA(7:0)...LBA(47:40))
(Identify Device words (99:98))/65536 time units per sector at the reference location

Table 110 Sector Time Array Entry (Linearly Interpolated)

Description
LBA of start of region (LBA(7:0)...LBA(47:40))
Position number in the range 0...32767

Table 111 Position Array Entry (Linearly Interpolated)

Description
Difference in position from last stream access to new stream access
Time that may be required to begin access at new stream access position, in
(Identify Device words (99:98))/256 time units

Table 112 Access Time Array Entry (Linearly Interpolated)

ime
Array
Hitachi hard disk drive specifications
161
Bytes
2
2
2
2
K*8
L*8
M*4
Bytes
n-(n+5)
(n+6)-(n+7)
Bytes
n-(n+5)
(n+6)-(n+7)
Bytes
n-(n+1)
(n+2)-(n+3)