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Content-Language: en-US References: To: questions@freebsd.org From: Chris Craft In-Reply-To: X-Forwarded-Message-Id: X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - giowm1069.siteground.biz X-AntiAbuse: Original Domain - freebsd.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - netgenius.org X-Source: X-Source-Args: X-Source-Dir: X-SGantispam-id: b1d157fe34b8d8c34c1d897a4264328f AntiSpam-DLS: false AntiSpam-DLSP: AntiSpam-DLSRS: AntiSpam-TS: 1.0 X-Spamd-Result: default: False [-3.78 / 15.00]; ARC_ALLOW(-1.00)[instance-us-central1-43c0.prod.antispam.mailspamprotection.com:s=arckey:i=1]; SUBJECT_ENDS_QUESTION(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.69)[-0.687]; DMARC_POLICY_ALLOW(-0.50)[netgenius.org,none]; R_DKIM_ALLOW(-0.20)[netgenius.org:s=default]; R_SPF_ALLOW(-0.20)[+ip4:185.56.86.0/24]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; RWL_MAILSPIKE_GOOD(-0.10)[185.56.86.132:from]; XM_UA_NO_VERSION(0.01)[]; HAS_X_SOURCE(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[netgenius.org:+]; ASN(0.00)[asn:396982, ipnet:185.56.86.0/24, country:US]; MIME_TRACE(0.00)[0:+,1:+,2:~]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; HAS_X_ANTIABUSE(0.00)[]; TO_DN_NONE(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; MLMMJ_DEST(0.00)[questions@freebsd.org]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[185.56.86.132:from] X-Rspamd-Queue-Id: 4XPd5V02sdz43Z5 X-Spamd-Bar: --- This is a multi-part message in MIME format. --------------5VnU5omhsB4kEsvvGNm08QVO Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit The message was intended to go back to the list... (Sorry, Matt!) -------- Forwarded Message -------- Subject: Re: How to zero a failing disk drive before disposal? Date: Thu, 10 Oct 2024 10:19:03 -0600 From: Chris Craft To: Matthew Seaman I was going to mention "Curie point", but this seems to be a complex topic. (Forum discussion: https://www.overclockers.com/forums/threads/what-is-the-curie-point-of-hdd-magnetic-platters.454159/ ) I think you'd be just fine putting it in the oven on the cleaning cycle (about 550F). -C On 10/10/24 10:13, Matthew Seaman wrote: > On 10/10/2024 16:17, Ralf Mardorf wrote: >> Someone might have the skills to extract data even after the plates have >> been shredded and fused into a lump. > > The Néel temperature for steel is typically somewhere around 200 -- > 500 ºC depending on the alloy.  Steel that is hot enough to "fuse into > a lump" will need to be significantly hotter than that -- nearly at > the melting point.  All of the magnetic information will have been wiped. > > Other ferromagnets useable for magnetic recording are going to behave > similarly. > >     Cheers, > >     Matthew > --------------5VnU5omhsB4kEsvvGNm08QVO Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit

The message was intended to go back to the list... (Sorry, Matt!)



-------- Forwarded Message --------
Subject: Re: How to zero a failing disk drive before disposal?
Date: Thu, 10 Oct 2024 10:19:03 -0600
From: Chris Craft <ccraft@netgenius.org>
To: Matthew Seaman <matthew@FreeBSD.org>


I was going to mention "Curie point", but this seems to be a complex topic. (Forum discussion: https://www.overclockers.com/forums/threads/what-is-the-curie-point-of-hdd-magnetic-platters.454159/ )

I think you'd be just fine putting it in the oven on the cleaning cycle (about 550F).

-C

On 10/10/24 10:13, Matthew Seaman wrote:
On 10/10/2024 16:17, Ralf Mardorf wrote:
Someone might have the skills to extract data even after the plates have
been shredded and fused into a lump.

The Néel temperature for steel is typically somewhere around 200 -- 500 ºC depending on the alloy.  Steel that is hot enough to "fuse into a lump" will need to be significantly hotter than that -- nearly at the melting point.  All of the magnetic information will have been wiped.

Other ferromagnets useable for magnetic recording are going to behave similarly.

    Cheers,

    Matthew

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