Deskstar 7K500 and Deskstar E7K500 Hard Disk Drive Specification
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4.4.5 Throughput
4.4.5.1 Simple sequential access
The following table illustrates simple sequential access for the enclosure.
The above table gives the time required to read a total of 8000h consecutive blocks (16,777,216 bytes) accessed by 128 read
commands. Typical and Max values are given by 105% and 110% of T respectively throughout following performance
description.
T = A + B + C + 16,777,216/D + 512/E (READ)
where
T = Calculated time (sec)
A = Command process time (Command overhead) (sec)
B = Average seek time (sec)
C = Average latency (sec)
D = Sustained disk-buffer transfer rate (byte/sec)
E = Buffer-host transfer rate (byte/sec)
Note: It is assumed that a host system responds instantaneously and host data transfer is faster than sustained data rate.
4.4.5.2 Random access
The following table illustrates simple sequential access for three-disk enclosure.
Table 12: Random
Access performance
The above table gives the time required to execute a total of 1000h read commands which access a single random LBA. Typi-
cal and Max values are given by 105% and 110% of T respectively throughout following performance description.
T = 4096(A + B + C+ 512/D + 512/E) (READ)
where
T = Calculated time (sec)
A = Command process time (Command overhead) (sec)
B = Average seek time (sec)
C = Latency
D = Average sustained disk-buffer transfer rate (byte/s)
E = Buffer-host transfer rate (byte/s)
Table 11: Simple Sequential Access performance
Operation Typical (sec) Max (sec)
Sequential Read (Zone 0) 0.29 0.30
Sequential Read (Zone 29) 0.59 0.61
Operation Typical (sec) Max (sec)
Random Read 55.5 58.1
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