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Old June 12th 18, 09:03 PM posted to alt.comp.hardware.pc-homebuilt,
Lynn McGuire[_3_]
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Posts: 134
Default 2T SSD SATA - $250

On 6/12/2018 2:02 PM, Paul wrote:
Lynn McGuire wrote:
On 6/12/2018 1:12 PM, Paul wrote:
Flasherly wrote:
Direct Chinese marketing - no warranty, no nothing.
Except, it is MICRON branded.
My Micron, I bought, a USA-distribution of their 256G SSD,
cost me four-times, per GByte, more.

IOW if that same drive, cost adjusted for this one, it would have cost
me $30 instead of $120 I paid:

Half off the usual market value, still, does tend to bear a little
weight on plattered drives.

It uses 3D TLC and is rated at 400TBW. That means,
as a 2TB drive, you can write it end to end 200 times.
Suitable for backups, subject to that limit.

And there should be QLC based drives soon, so the price
might come down a tiny bit more. The TBW could be worse
on the QLC based drive (four bits stored per Flash cell,
Flash cells chained in cylindrical columns in the chip).

*** Paul

Only 200 writes per sector ?


It's a TBW rating, and I presume takes write amplification
into account.

I don't think I have the skill set to map the flash chip
endurance rating, to TBW. Half the time, we can't get an
honest endurance number for the flash anyway.

You know, even hard drives have TBW ratings now. Something
about the expected amount of usage so that a unit will
pass the warranty period in one piece. Maybe an enterprise
class hard drive might have a 550TBW rating. Which you might
easily exceed without too much effort in the run of a year.
And the different price ranges of drives, have a rough
relationship to the TBW value. The entry level drives have
lower values than that.

You can also get into the old "IBM problem", where IBM started
putting information in datasheets, indicating the DeathStar
couldn't be operated 24 hours a day forever. And that notion
is leaking back into datasheets now too. It's all a bit
discouraging. There hasn't been a stink about it, like when
IBM pulled that the first time. The other companies
are not getting called on it.

There is some move to make platters thinner (so they
can stuff more of them into high capacity drives).

There was yet another mention of glass platters
coming back.

The only thing I haven't seen recently, is any
more experimental results on "zero flying height"
drives. HGST managed to grind the heads off
the arm in about 30 days, while flying at zero
nanometers, in a lab experiment.

At least there's no sign an SSD can't have the power
left on all the time :-) Even if the write life
leaves something to be desired (imagine if QLC
needs "refresh writes" to improve the error rate
over time...). All the tech seems to be headed
into the dumper.

** Paul

I was really hoping that we were heading to 100 year capable devices.