Posts by Chris Jones 3 publicly visible posts • joined 3 Nov 2007
Didn't Dell say a while back that they only expected to shift about 20,000 Ubuntu machines a year? If my memory serves me well then they have doubled their expectations in under a year.
That seems like a) they knew that not everyone would put their money where their mouth was, b) they underestimated how much the Bunty love is spreading.
when you run smartctl on your disk and look at the Load_Cycle_Count entry, and the RAW_VALUE column, you may very well *not* be seeing the number of times your hard disk heads have unparked.
SMART is not designed to reliably report counters, instead it reports an indication of health.
You will see VALUE, WORST and THRESH columns - these are the useful ones. Load_Cycle_Count is an Old_Age type of SMART value, which means the VALUE starts at 100 and counts down to THRESH (usually zero).
When that counter reaches zero, it means you have reached what the manufacturer of the drive believes is the end of its expected lifespan.
By way of an example, my thinkpad x40 reports a Load_Cycle_Count RAW_VALUE of almost 3 trillion, which for a 14 month old laptop is very clearly not a real counter. The VALUE is actually only about 71, so I've used less than 1/3 of the drive's life, even though I've had aggressive laptop mode enabled in Ubuntu for at least a year.
Some drives will report the absolute count of head unparks in the RAW_VALUE column, but please don't assume that it is always the case. Use SMART for what it is supposed to be, an indication of health that is interpreted by the drive's firmware (ie by the manufacturers). That is why there are thresholds and stuff.
Sadly this entire issue has blown up because of a mis-interpretation of data and some broken assumptions about what Ubuntu does when you are on battery.
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