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Power-on hours is intended to indicate a remaining lifetime prediction for hard drives and solid state drives, generally, "the total expected life-time of a hard disk is 5 years" [3] or 43,800 hours of constant use. [4] [5] Typically, after a disk reaches 5 years of power-on time, the disk is more likely to fail.
Average access time: ... Average lifespan: c. 2000 hrs MTBF ... the typical speed of a hard drive in an average desktop computer is 7,200 rpm, ...
The first HDD [11] had an average seek time of about 600 ms. [12] and by the middle 1970s, HDDs were available with seek times of about 25 ms. [13]Some early PC drives used a stepper motor to move the heads, and as a result had seek times as slow as 80–120 ms, but this was quickly improved by voice coil type actuation in the 1980s, reducing seek times to around 20 ms.
For example, a common specification for PATA and SATA drives may be an MTBF of 300,000 hours, giving an approximate theoretical 2.92% annualized failure rate i.e. a 2.92% chance that a given drive will fail during a year of use. The AFR for a drive is derived from time-to-fail data from a reliability-demonstration test (RDT). [3]
[17] Hard drives with S.M.A.R.T.-reported average temperatures below 27 °C (81 °F) had higher failure rates than hard drives with the highest reported average temperature of 50 °C (122 °F), failure rates at least twice as high as the optimum S.M.A.R.T.-reported temperature range of 36 °C (97 °F) to 47 °C (117 °F). [16]
This value should only be understood conditionally as the “mean lifetime” (an average value), and not as a quantitative identity between working and failed units. [1] Since MTBF can be expressed as “average life (expectancy)”, many engineers assume that 50% of items will have failed by time t = MTBF. This inaccuracy can lead to bad ...
Also, while earlier versions of the technology only monitored hard drive activity for data that was retrieved by the operating system, this latest S.M.A.R.T. tests all data and all sectors of a drive by using "off-line data collection" to confirm the drive's health during periods of inactivity.
Solid-state drive (SSD) Hard disk drive (HDD) Price per capacity SSDs are generally more expensive than HDDs and are expected to remain so. As of early 2018, SSD prices were around $0.30 per gigabyte for 4 TB models. [23] HDDs, as of early 2018, were priced around $0.02 to $0.03 per gigabyte for 1 TB models. [23] Storage capacity