> On Nov 18, 2020, at 5:56 PM, Chuck Guzis via cctalk <cctalk@classiccmp.org>
> wrote:
>
> Tangential to this, I've long wondered about some things relating to
> SSDs. Are there any solid figures on their retention period after years
> of being unpowered?
>
> The reason I ask is that I've long been in the habit of simply shelving
> an old hard drive when I upgrade or replace a system. I've got hard
> drives that still work that hail back to the days of OS/2 1.1; some
> larger ones go back to the 1970s.
You should be able to find the answer in the drive specs.
As I understand it, there are two rather different ranges of answer depending
on whether you're looking at an enterprise class drive, which is optimized for
high speed and large total amount of data written, vs. a consumer drive. The
power-off retention spec is much shorter for the enterprise drives. I forgot
the numbers; I vaguely remember it being less than a year.
If the drive has power it will do something analogous to DRAM refresh to keep
the bits in good shape. But it seems that the HDD rule that you can just set a
drive on the shelf for a decade (ditto with other magnetic media) does not
necessarily carry over to SSD.
paul
