On Thu, Mar 15, 2018 at 04:46:30PM +0100, Kashyap Chamarthy wrote:
> (Sorry, accidentally dropped the lists. Adding it back & re-posting my
> off-list response.)
(Now add the missing linux-usb@vger.kernel.org list for real. Not
trimming the full e-mail intentionally as I missed to Cc 'linux-usb'.)
> On Thu, Mar 15, 2018 at 04:05:53PM +0100, Kashyap Chamarthy wrote:
> > On Thu, Mar 15, 2018 at 03:33:46PM +0100, Douglas Gilbert wrote:
> > > On 2018-03-15 02:44 PM, Douglas Gilbert wrote:
> > > > On 2018-03-15 01:45 PM, Martin K. Petersen wrote:
> > > > >
> > > > > Kashyap,
> > > > >
> > > > > > /me naively wonders if it has anything to do with accessing it via
> > > > > > Linux.
> > > > >
> > > > > I'm guessing that the drive doesn't actually support SCSI UNMAP. I
> > > > > have
> > > > > a T3 that reports all the right things in the bl/lbpv VPD pages but
> > > > > also
> > > > > has lbpme set to 0.
> > > > >
> > > > > Interestingly enough, my T3 does appear to be a regular SATA drive
> > > > > behind a USB bridge. Have you tried to issue a DSM TRIM command via
> > > > > ATA
> > > > > passthrough?
> > > >
> > > > hdparm can do that. Look for "EXCEPTIONALLY DANGEROUS. DO NOT USE THIS
> > > > OPTION!!" in its manpage :-)
> >
> > Hehe, near as I see, that's dangerous only if you have data on the disk.
> >
> > This is an empty SSD that I haven't put any data in it, I should remind.
> > :-) In that case, I'll assume it is "safe" to tinker with the above.
> >
> > > IOWs, using Mark Lord's example:
> > > hdparm --trim-sector-ranges 1000:4 /dev/sdz
> > >
> > > That will attempt to trim lba 1000, 1001, 1002 and 1003 on /dev/sdz
> >
> > Thanks; I should first educate myself more on this before I tinker with
> > the above. One Ubuntu wiki page claims: "To wipe out contents of an SSD,
> > SATA secure erase is the way to go",
Never mind about "secure erase", even trying to set password via
`hdparm' for this T5 SSD (still connected via 'Thunderbolt'):
$> hdparm --user-master u --security-set-pass $SECRET /dev/sdc
Fails with the unactionable & useless error:
"SECURITY_SET_PASS: Input/output error"
> > and '--trim-sector-ranges' is only
> > "experimental and for benchmarking purpose".
> >
> > Just to recap: My goal is to clean (insofar as possible) the SSD of all
> > and any / all pre-loaded programs & re-claim space.
> >
> > ---
> >
> > Related: The ATA Secure Erase wiki page claims[*] if you do it (Secure
> > Erase) via USB interface, you might brick the SSD. I'm using the
> > 'Thunderbolt' interface, and the said wiki page doesn't say anything
> > useful about it.
> >
> >
> > [*] https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase
--
/kashyap
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