Power-on hours (POH) is the length of time, in hours, that electrical power is applied to a device.
It is used to predict drive failure, supported by manufacturers such as Samsung, Seagate, Toshiba, IBM (Hitachi), Fujitsu, Maxtor and Western Digital.
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" or 43,800 hours of constant use.
Once a drive has surpassed the 43,800 hour mark, it may no longer be classed as in "perfect condition".
It is primarily used in:
- "Wayback Machine" (PDF). 2001-06-12. Archived from the original on 2001-06-12. Retrieved 2018-02-01.CS1 maint: BOT: original-url status unknown (link)
- Pinheiro, Eduardo; Weber, Wolf-Dietrich; Barroso, Luiz André (2007). "Failure Trends in a Large Disk Drive Population". Cite journal requires