power on calculation

Can anyone tell me what 1.5 million hours given in reliability specs is in years, this just fries my brain?

1,500,000 / 8,766 = 171 years

No need for back-ups, then.

That's mad for an SSD

Such high MTBF values must necessarily be estimates and, as such, are only really of interest to data centres where hundreds (and perhaps thousands) of devices will be in continuous use. Fretting about how long your SSD drive is going to last you is a waste of time. Bear in mind that the NAND gates in flash memory start to fail after a few thousand write cycles and so your SSD will start to lose capacity soon enough (as sectors are reallocated) even if you never experience an outright failure.

Data centres can measure SSD shrinkage rates for themselves and plan accordingly but they must rely on manufacturers' estimates in order to plan for (inevitable) outright failures. For you and me, things are simpler but less certain. Your SSD may last for months or years. Enjoy the high speeds that it gives you but make regular backups. Hope for the best, prepare for the worst, and forget about MTBF values.

Edited by micksharpe (Fri 01-Jan-16 16:24:38)

In reply to a post by micksharpe:

1,500,000 / 8,766 = 171 years

No need for back-ups, then.

Hmm, as 2100 isn't a leap year, 8766 (365.25*24) is slightly inaccurate for a period extending into the next century.



Me pedantic? Surely not

Happy new year, Tony.

How much "green" energy would we need to extract from the spin of the earth to slow it down enough that we would need to make 2100 a leap year?

In reply to a post by cheshire_man:

In reply to a post by micksharpe:

1,500,000 / 8,766 = 171 years

No need for back-ups, then.

Hmm, as 2100 isn't a leap year, 8766 (365.25*24) is slightly inaccurate for a period extending into the next century.



Me pedantic? Surely not

Not pedantic enough!

The 171 years was only accurate to zero decimal places and adding another 24 hours gives exactly the same figure.

In reply to a post by TinyMongomery:

In reply to a post by cheshire_man:

In reply to a post by micksharpe:

1,500,000 / 8,766 = 171 years

No need for back-ups, then.

Hmm, as 2100 isn't a leap year, 8766 (365.25*24) is slightly inaccurate for a period extending into the next century.



Me pedantic? Surely not

Not pedantic enough!

The 171 years was only accurate to zero decimal places and adding another 24 hours gives exactly the same figure.

Indeed, it was the 365.25 that was the root (pedantic) inaccuracy, not the rounded 171 years; though in my defence I didn't claim 171 years was inaccurate

To be utterly pedantic (or sad! Aren't spreadsheets wonderful...), assuming the clock started at midnight New Year's Eve/New Year's day, the 150,000 hours would be up 6,250 days later, at midnight 12/13th February 2187, 171.2986 years later.

I strongly suspect that nobody here will be around to verify that life expectancy claim...

I suspect that most SSDs would last a very long time indeed, providing that you never write any data on them.

That sounds like Schr�dinger's SSD.

The start date wasn't specified. You have assumed that the start date is today. The start date may not be for 100's of years and therefore could actually cross the 400 year boundary where there is a leap year at the end of the century.

The problem is a year as you are all using it is not an accurate measurement. You need to measure via a solar year which according to my friend Google is 365 days 5 hours 48 minutes 46 seconds. So a year is 365.242199074074 days.

Therefore 1,500,000 hours is 171.1193289 solar years. Or, rounded to 0 decimal places it would be 171 years. Now, where did this start?

EDIT : PS - this is of course an approximation and the solar year is not precise as the earths orbit is not 100% stable.

Edited by ian72 (Tue 05-Jan-16 11:42:46)

In reply to a post by ian72:

...as the earths earth's orbit is not 100% stable.

Virtual Titus mode correction

The apostrophe thief must have stolen it in between me posting and you viewing it

What a feeble excuse! I must remember it though