On Saturday 27 December 2008 15:29, Carlos E. R. wrote:
On Saturday, 2008-12-27 at 17:50 -0500, James Knott wrote:
Those memory/drives, can they stand infinite write cycles? Because flash memories can't.
Mechanical drives can't either.
Of course they can. The limit is in the thousands of hours of usage, not in the write cycles. There is no wear on the surface or the head because of changing the magnetization. They don't touch.
Sure they do, at the precise instant the drive dies of a head crash. Of course, on rotating magnetic media, the read vs. write distinction is entirely moot and as you say, the lifetime is measured in hours during which those heads are "flying" over the platter. I'd be surprised if seeking were unrelated to the probability of a head crash, but still that's entirely apart from whether the purpose of the seek was to read or to write. I suppose if you conducted some massive study, you might be able to find out that when the head was writing that there was some minute additional deflection which created a tiny increase in the probability of a head crash (possibly also data-dependent, in that the relationship between the magnetization that already exists on the platter and that being imposed by the write operation would modify that (hypothetical) additional force on the head. What people don't often realize is that the aerodynamic forces on drive heads are really quite large and are balanced by a mechanical force on the head holding it in the proper proximity to the platter. That's why drives can operate regardless of their orientation within the gravitational field (or in zero G).
-- Cheers, Carlos E. R.
Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org