Hitachi HDS728080PLAT20 Specifications - Page 29

The terms "Typical" and "Max" are used throughout this document and are defined as follows: Typical The average of the drive population tested at nominal environmental and voltage conditions. Max Maximum value measured on any one drive over the full range of the environmental and voltage conditions. The seek time is measured from the start of the actuator's motion to the start of a reli- able read or write operation. A reliable read or write implies that error correction or recovery is not used to correct arrival problems. The average seek time is measured as the weighted average of all possible seek combinations. max Σ (m10 n)(Tnin + Tnout) n=1 Weighted Average (max + 1)(max) where max n Tnin Tnout = Maximum seek length = Seek length (1 to max) = Inward measured seek time for an n track seek = Outward measured seek time for an n track seek 4.5.2.2 Full stroke seek time (without command overhead, including settling) Table 7: Full stroke seek time Function Read 40-80GB Write 40-80GB Read (Quiet Seek mode) Write (Quiet Seek mode) Typical (ms) 15.1 16.1 32.5 33.5 Max (ms) 18.1 19.1 35.5 36.5 Full stroke seek is measured as the average of 1,000 full stroke seeks with a random head switch from both directions (inward and outward). 4.5.2.3 Head switch time (head skew) Table 8: Head switch time 90 kTPI Head switch time-typical (ms) 1.4 Head switch time is defined as the amount of time required by the fixed disk to complete a seek of the next sequential track after reading the last sector in the current track The measuring method is given in 4.5.5, "Throughput" on page 28. Deskstar 7K80 Hard Disk Drive Specification 25