Throughput; Figure 13. Simple Sequential Access Performance; Figure 14. Random Access Performance; Simple Sequential Access - IBM DTLA-305040 - Deskstar 41.1 GB Hard Drive Specifications

4.4.6 Throughput

4.4.6.1 Simple sequential access

Sequential
read
DTLA-305XXX
Zone 0
Zone 14

Figure 13. Simple Sequential Access performance

The above table gives the time required to read/write for a total of 8000x 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.
Note: It is assumed that a host system responds instantaneously and host data transfer is faster than
sustained data rate.
T = A + B + C + 16,777,216/D + 512/E
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)

4.4.6.2 Random access

Random read
DTLA-305XXX
DTLA-307XXX

Figure 14. Random Access Performance

The above table gives the time required to execute a total of 1000h read/write commands which access a
random LBA.
T = (A + B + C + 512/D + 512/E) * 4096
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/sec)
E = Buffer-host transfer rate (byte/sec)
Typical (sec)
DTLA-307XXX
0.57 0.48
1.20 0.95
Typical (sec)
65
55
Deskstar 40GV & 75GXP hard disk drive specifications
Max (sec)
DTLA-305XXX
0.60
1.26
(READ)
Maximum (sec)
(READ)
16
DTLA-307XXX
0.50
1.00
68
57