Power-on hours

Power-on hours (POH) is the length of time, usually in hours, that electrical power is applied to a device.
A part of the <a href="/facts/Self-Monitoring,_Analysis,_and_Reporting_Technology/1w5jD2Bf">S.M.A.R.T.</a> attributes (originally known as IntelliSafe, before its introduction to the public domain on 12 May 1995, by the computer hardware and software company <a href="/facts/Compaq/6LuhWTE7">Compaq</a>),
It is used to predict drive failure, supported from almost all <a href="/facts/Hard_disk_drive/kekLSGSE">Hard Drives</a> and <a href="/facts/Solid-state_drive/aMHBy8gU">SSds</a>.
Power-on hours is intended to indicate a remaining lifetime prediction for hard drives and <a href="/facts/Solid_state_drive/aMHBy8gU">solid state drives</a>, generally, "the total expected life-time of a hard disk is 5 years" or 43,800 hours of constant use.
Typically, after a disk reaches 5 years or 43,800 of power-on time, it is no longer in perfect condition and therefore is more likely to fail. However, some older and newer devices can still work perfectly fine even after. Some devices have even reached more than 10 years of power-on time without showing any problems or errors!
Google tested over 100,000 consumer grade serial and parallel ATA hard disks, finding evidence that S.M.A.R.T. attributes like POH played a heavy role in device failures.

Power-on hours open-in-new

Power-on hours