Paul wrote in part:
HGST is owned by Western Digital.
The category is "Enterprise". 16TB for $577 USD.

They might have done HelioSeal before WDC did.
Unlike regular air-breathing drives (which use a breather hole),
the HelioSeal are sealed and have a Helium gas atmosphere
inside. Helium drives draw less power, or allow more platters
(with the platters eventually returning to glass, just like
IBM days - that's how they plan to make thinner platters).

Glass? Maybe OK for hoop stress at 10krpm (1.8 MPa / 260 psi)
but you might want to be careful with the jerk at spinup.

The Helium gas is guaranteed to stay inside for 5 years.

Why not Hydrogen? _Much_ cheaper and better properties.
Oh, yeah, invokes the LZ Hindenburg at the hands of Joisey
longshoremen (What are grounding strap?) But seriously, the
heat from that small a volume is less than in a cup of coffee.

Balloons should not be filled with pure hydrogen unless you are
real careful or making YouTube videobangs. In large numbers
they'd be a hazard especially with the static electricity.
Nor does Nitrogen dilution help much.

What part of that history sez "16TB for $79" ? :-)
Paul

-- Robert