Stan Brown wrote:
On Sun, 10 Mar 2019 01:12:45 -0500, Paul wrote:
Stan Brown wrote:
But since I have a detached garage, I wondered about
just storing the "off site" drive in the garage. The garage isn't
climate controlled, so the drive would be out of the weather but
subject to temperature fluctuations from 0°F to the 90s -- probably
not in the same day. :-)

The enclosure is not sealed.

Each drive has a breather hole.

As the temperature changes, the drive "breathes in and out".
A high humidity environment will eventually ruin the platters.

If you're going to do that, use an air tight enclosure,
and include desiccant packs inside the housing.

...

Find a storage space with better climate controls.

Thanks for the information, Paul. I'm glad I asked, because my house
isn't air conditioned either. The temperature variations are less,
about 68 - 90 °F, but it does get humid in the summer. So I guess
even the drive that's in the house needs to be packed better.


The breather hole uses a "labyrinth" design, to make the effective
filter path length longer, so it's harder for moisture to get in.

But I've had two disk failures during high humidity times in the
house, and zero disk failures when the HVAC is fully functional
(25% RH in winter, as I have no humidifier on the side of the
furnace, and about 40% RH when on AC in summer). Generally, the
disks are in danger, when the carpeting begins to stink (mildew) :-/

I've never been able to find first hand info on the humidity
question. Some IBM disk specs have a graph for humidity and
temperature, showing the "acceptance polygon" on the graph. A
set of conditions considered safe. But there's no accompanying
text, and no way to ensure I'm interpreting the graph properly.

There have been disk drives, that when the cover is removed,
the (air) filter packs inside the drive are absolutely filthy,
and it looks like the plating on the platter has failed. But I
haven't seen a picture like that for any newer drives. Just
the old ones used to do that. The filter packs were black, from
a coating of particulate. And the hard part to understand, is
how the disk could run so long, building up that dirty filter,
without head crashes happening. If the plating was coming off,
the disk should die before the filter pack gets dirty.

I don't have any really good references for this topic,
and I'm still looking for evidence from a reliable source.

Paul