The Race to Seal Helium HDDs (2021)

Original Article ↗ Hacker News Discussion ↗

Vacuum vs. Helium in HDDs

  • Several comments ask why not use vacuum instead of helium.
  • Concerns raised:
    • Structural: vacuum leads to implosion risk; cases must be much stronger.
    • Thermal: vacuum hampers cooling via gas, though heat can still conduct through metal.
    • Mechanics: HDD heads ride on a gas “air bearing”; in vacuum they would crash or weld to platters and the drive would not function.
  • A startup claiming “vacuum HDDs” is mentioned, but commenters see little evidence of traction.

Role of Gas and Possible Alternatives

  • Gas is essential as a bearing medium; not just for shock protection but for basic operation.
  • In vacuum, metal–metal contact could cause friction or cold/vacuum welding.
  • Some speculative ideas: magnetic bearings and special encodings, but these are purely hypothetical in the thread.

Helium, Hydrogen, and Other Gases

  • Helium is hard to contain due to small atoms; containment requires careful sealing and materials.
  • Hydrogen is discussed:
    • More reactive and can diffuse into metals.
    • Fire/explosion risk is low inside a sealed drive with no oxygen, but manufacturing-scale handling is a concern.
  • Some ask about neon; it’s noted as scarcer and more expensive than helium.
  • Debate over whether helium is the “tiniest atom”; clarification that it’s the smallest stable neutral atom, with side discussions on ions and muonic atoms.

Helium Supply and HDD Impact

  • Rough back-of-envelope: a 3.5" drive contains a small fraction of a gram of helium.
  • Comparisons: MRI machines consume orders of magnitude more helium over their lifetimes.
  • Consensus: HDDs use helium, but likely not a dominant global consumer; unclear overall impact.

Sealing and Manufacturing Techniques

  • Key techniques mentioned: laser welding of thin foil covers, friction-stir welding, special aluminum alloys, glass–metal feedthroughs, and nickel plating for solderability.
  • Some commenters argue these techniques are longstanding industrial practices, not radical inventions, though integrating them at HDD scale is still nontrivial.

Reliability and SMART 22

  • SMART attribute 22 tracks helium level; failure is treated as an immediate return/replace condition.
  • Multiple users report multi-year drives still showing 100% helium level.
  • Recommendation to run SMART self-tests (short/long) on new drives and use failed tests as return justification.

HDD vs. SSD Demand

  • Discussion notes helium HDDs remain standard for high-capacity, cost-sensitive storage.
  • SSDs are still much more expensive per TB and don’t match highest single-drive capacities in this timeframe.