Thanks — I’ll cover every point you asked about for your specific drives (WD10JPVX‑08JC3T5, HGST HTS541010A99E662, Seagate ST500LM030). I’ll give direct answers first, then detailed explanations, practical checks/commands, and a short action plan. I’ve cited the forum/technical notes you and I have already used so you can follow the sources I relied on. If you want, I can next fetch the official product pages / datasheets from Seagate/WD/HGST to add manufacturer specs (I recommend that for the final authoritative numbers).
TL;DR — direct answers
- Placing a powered 2 cm from a large CRT: permanent erasure/demagnetization is extremely unlikely for those modern drives (they use high‑coercivity thin‑film media). The real risk while the HDD is powered and the CRT is on is transient EMI/I/O errors (especially during the CRT’s degauss/power‑up pulse). Move the drive 10–30 cm away while the CRT is powered to remove virtually all risk.
- Minutes vs hours exposure: for magnetic erasure the instantaneous field strength matters far more than time; a very strong field will erase quickly, while a moderate field over time is still unlikely to erase modern platters. Exposure time matters for cumulative risks (thermal ageing, corrosion, EMI fatigue, mechanical/thermal stress) — those increase with longer powered operation in a hot/humid environment.
- 2.5" vs 3.5" for archival: 2.5" drives can be used for long‑term archiving, but 3.5" desktop/enterprise drives are generally more robust for long, stationary archives (better mechanical design, higher workload/thermal characteristics). If you use 2.5" drives accept extra precautions: redundancy, regular integrity checks, humidity protection, and scheduled migration.
- Mechanical wear (daily use) vs cold storage (yearly power‑on): they are different failure modes. Daily multi‑hour use increases mechanical wear (spindle hours, bearings, head actuation) and operating thermal stress. Rare powering reduces mechanical wear but increases continuous environmental exposure (heat/humidity) that accelerates corrosion and slow magnetic ageing. Use verification + migration to mitigate both.
- Storage at 31–38 °C, 55–66% RH: this won’t instantly “demagnetize” your platters, but it does accelerate long‑term thermal-driven bit‑decay and increases corrosion risk. That raises the probability of errors over years vs cooler/drier storage. Increase verification frequency and humidity protection in that climate.
- Do 2.5" HDDs need rewrite/refresh before 5 years like flash? No — HDD magnetic media don’t have NAND charge‑loss behavior. You do not need to rewrite everything yearly. Still, best practice for archival data is checksum verification and media migration every few years (commonly recommended 3–7 years for critical archives) plus redundancy.
Detailed explanations and sources
A. Why modern drives resist ordinary magnets / CRT fields
- The WD10JPVX and HGST travelstar models you listed use modern perpendicular (PMR/CMR) thin‑film platters with high coercivity; Seagate’s ST500LM030 uses SMR but also on modern high‑coercivity platters. That media is engineered to resist stray household magnetic fields, so ordinary CRT magnets are orders of magnitude weaker than the fields required to reliably erase platters. Consumer CRTs do create measurable fields (and a brief degauss pulse at power‑up) but those are normally not strong enough to wipe modern HDD media.
B. What a powered CRT actually risks
- If the HDD is powered and actively reading/writing while a CRT is powered on (particularly at the degauss moment), you can get transient EMI or induced noise that can cause I/O errors or corrupted writes. That’s the realistic risk — not platter demagnetization in normal CRTs. If the HDD is powered off and heads parked, permanent demagnetization is extremely unlikely. Practical safety: don’t perform important read/writes with the HDD within a few cm of a powered CRT; moving it 10–30 cm removes almost all risk.
C. Field strength vs exposure time
- For magnetic erasure the dominant variable is field strength — a very strong DC/low‑frequency field (industrial degausser or a very large rare‑earth magnet at close contact) will erase quickly. Long exposure to weak/moderate fields is unlikely to erase modern high‑coercivity media, but longer powered operation near EMI sources increases chance of transient errors and exposes electronics/firmware to more stress. So: strength dominates for direct magnetic erasure; time matters for cumulative thermal/EMI/mechanical risk.
D. 2.5" vs 3.5" for long‑term archiving
- 2.5" drives are used for archives and are fine for medium‑term retention (several years). 3.5" desktop/enterprise drives are usually chosen for large, stationary archives because they have better mechanical headroom and thermal dissipation. Either can be used with the right process (redundancy, periodic checks, environmental protection), but 3.5" drives are commonly preferred for long, heavy‑duty archival pools.
E. Mechanical wear, lubricant, and usage patterns
- Mechanical wear correlates with operating hours, start/stop cycles, and shock/vibration while operating. Daily hours raise wear and increase chances of mechanical failure. Cold storage reduces mechanical wear but leaves media exposed to the environment (heat + humidity) continuously, which accelerates slow magnetic processes and corrosion if humidity is high. In other words, daily use shortens mechanical lifetime; continuous hot/humid storage shortens retention lifetime from corrosion and thermal bit‑ageing. Best approach: minimize unnecessary powered time, but do periodic verification and refreshing to catch problems early.
F. Hot/humid climate (31–38 °C, 55–66% RH)
- That range is warmer and more humid than the archival ideal (≈20–25 °C and <50% RH). It won’t instantly demagnetize platters, but it increases the rate of thermal agitation (raising long‑term bit‑error probability) and increases risk of corrosion/oxidation of electronic parts and connectors if condensation or persistent high RH occurs. In practice that means higher long‑term failure probability and a recommendation for more frequent checks and migration.
Checks, commands and what to do when you “energize” a drive
1) SMART checks (recommended tool: CrystalDiskInfo)
- Important SMART fields to watch: Reallocated Sector Count, Current Pending Sector Count, Uncorrectable Sector Count, G‑Sense / Shock (if present). If any of those increase suddenly, copy data off immediately.
2) Verify files with hashes (PowerShell)
- Compute SHA‑256 for a file:
- PowerShell:
Get-FileHash "C:\path\to\file.ext" -Algorithm SHA256
- To hash all files in a folder and save results (example):
Get-ChildItem -Path "D:\ArchiveFolder" -Recurse -File | ForEach-Object { Get-FileHash $_.FullName -Algorithm SHA256 | Select-Object Hash, Path } | Export-Csv D:\hashes.csv -NoTypeInformation
- Re-run and compare hashes on each audit.
3) Basic “energize” checklist (what to do every check)
- Move drive to a room corner away from CRTs or noisy motors (10–30 cm minimum).
- Mount/enclose the drive stably (avoid vibration).
- Power on, run CrystalDiskInfo — note SMART attributes above. If anything abnormal (reallocated/pending/uncorrectable > 0 or rising), copy data immediately.
- Mount and open a sample of files and/or run checksum verification across a representative set.
- If checks are clean, consider copying the entire archive to a fresh drive every 3–7 years (shorter if environment is hot/humid).
Practical protective steps for your climate
- Store in airtight anti‑static bags or small airtight containers with silica gel/desiccant (replace/regenerate periodically); use insulated boxes if you can. This reduces humidity exposure a lot.
- Keep at least two independent copies (3‑2‑1: three copies, two media types, one off‑site) — the only reliable protection.
- Check drives every 6–12 months given your 31–38 °C / 55–66% RH environment (increase frequency if you see any changing SMART attributes).
Short answers to the small, repeated questions you asked
- “Do 2.5" HDDs lose magnetic strength near a CRT at 2 cm?” — Extremely unlikely to lose platter magnetization permanently from a consumer CRT; transient errors while operating are the practical concern. Move the drive a bit and avoid active read/writes during CRT power‑up.
- “Does magnetic degradation depend more on field strength or time?” — Field strength dominates for direct demagnetization; time/exposure
dominates for thermal/chemical/mechanical ageing and cumulative risks.
- “Need to refresh/rewrite before 5 years like flash?” — No. HDDs don’t have NAND charge leakage. Instead: verify via checksums and refresh/migrate to new media on a schedule (commonly 3–7 years) and keep redundant copies.
Offer to fetch manufacturer pages / datasheets
- If you want the vendor’s exact storage/operating temperature & humidity ranges and any specified shock/coercivity/park features, I can fetch the official product pages or datasheets for:
- WD10JPVX‑08JC3T5 (WD Blue 1 TB 2.5")
- HGST HTS541010A99E662 (HGST Travelstar 1 TB)
- Seagate ST500LM030 (ST500LM030 Barracuda/other)
Those datasheets will give the manufacturer’s operating and non‑operating temperature/humidity specs (the authoritative numbers). I recommend we fetch those next if you want exact manufacturer specs.
Quick action plan (what to do in the next 30 minutes)
- If the drive is currently stored 2 cm from a powered CRT, move it 10–30 cm away. That removes nearly all practical risk.
- If the drive contains important data and you don’t already have two independent copies, create a second copy immediately (external drive, cloud, or M‑DISC / tape if available).
- On your next check (now or within a week): run CrystalDiskInfo and produce SHA‑256 hashes for a few critical files (I can give step‑by‑step commands and interpret results).
Which of the following do you want me to do next?
- Fetch and paste the official datasheets / product pages (Seagate, WD, HGST) and quote the exact operating/storage temp & humidity and shock specs. (Recommended.
- Walk you step‑by‑step through installing/running CrystalDiskInfo and interpreting SMART attributes for your two drives.
- Give the PowerShell scripts to generate and later verify SHA‑256 hashes for a folder (I’ll tailor it to Windows).
Tell me which of those you want and I’ll proceed.