[Solution not found but problem went away] Single boot: NTLD

Kernels & Hardware, configuring network, installing services

Re: Single boot: NTLDR not found, press any key to restart

Postby Head_on_a_Stick » 2020-09-03 15:16

Partitioning tools do not delete filesystems or their contents so if a partition is deleted and then re-created the files will still be present.
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Re: Single boot: NTLDR not found, press any key to restart

Postby cuckooflew » 2020-09-03 18:10

To completely remove everything from the hd, I use the 'dd' command. There might be other methods, but I don't know of any . When I get a "new"(for me it is new) used PC or laptop, say for example at a garage sale, or pawn shop, If it has MS windows on it, or even if the old system has all ready been removed, (supposedly), any way, before installing anything , I plug in my "live" usb drive, boot with that, then I run the 'dd' command on the UNMOUNTED, HD, it is important it is not mounted, ( I think, and the 1 or 2 times I did this with the drive mounted, it did not work out well).
Also, after the 'dd' command, the clean drive will need to be formatted , as needed. You can use Gparted or 'fdisk' and 'mkfs', or even FreeDos , 'format' command. There are many other tools, or software that can be used as well for the partitioning and formatting.
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Re: Single boot: NTLDR not found, press any key to restart

Postby Head_on_a_Stick » 2020-09-03 18:28

For solid-state drives blkdiscard(8) is an instantaneous alternative to leaving dd(1) running for hours.
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Re: Single boot: NTLDR not found, press any key to restart

Postby Caitlin » 2020-09-04 09:09

Do I have to seep saying it? I'm not booting from a stick and I don't (think I) have UEFI. In any case, I did NOT have a stick there when I booted.

I'm closing this thread as No solution found but problem went away.

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Re: Single boot: NTLDR not found, press any key to restart

Postby reinob » 2020-09-04 09:35

Caitlin wrote:Do I have to seep saying it? I'm not booting from a stick and I don't (think I) have UEFI. In any case, I did NOT have a stick there when I booted.


This is the first time you write that the stick wasn't there while booting.
And you/we still don't know if you have UEFI or not.

In lack of a crystal ball, I guess you're right it makes no sense to follow up.
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Re: [Solution not found but problem went away] Single boot:

Postby p.H » 2020-09-06 14:16

Head_on_a_Stick wrote:Partitioning tools do not delete filesystems or their contents so if a partition is deleted and then re-created the files will still be present.

fdisk from current util-linux offers to erase the filesystem signature when it finds one in a newly created partition. Better give the right answer if you want to keep the data. I would not be surprised if some "smart" partitioning tools erase the existing signature or issue discard/TRIM for the whole partition without even asking when deleting or creating a partition.

Head_on_a_Stick wrote:For solid-state drives blkdiscard(8) is an instantaneous alternative to leaving dd(1) running for hours.

TRIM/discard is not an erase command. It just sends the information that the data are not useful any more and may be erased to the drive controller. Actual erasure may be delayed.
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Re: [Solution not found but problem went away] Single boot:

Postby Head_on_a_Stick » 2020-09-06 15:38

p.H wrote:Actual erasure may be delayed

Well yes but the command is instant and functionally equivalent to a "secure erase" [sic] using hdparm(8).
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Re: [Solution not found but problem went away] Single boot:

Postby p.H » 2020-09-06 17:17

Head_on_a_Stick wrote:the (blkdiscard) command is instant

The goal is to make sure that data are erased, not to return quickly. Some discarded blocks may even never be erased, for exemple if the controller stops garbage collection and block erasure when the free block count exceeds a threshold.

Head_on_a_Stick wrote:and functionally equivalent to a "secure erase" [sic] using hdparm(8).

Source ?
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Re: [Solution not found but problem went away] Single boot:

Postby Head_on_a_Stick » 2020-09-06 17:52

p.H wrote:The goal is to make sure that data are erased

There is only one way to make sure that all data is erased on a solid-state device: https://www.youtube.com/watch?v=sQYPCPB1g3o

p.H wrote:
Head_on_a_Stick wrote:and functionally equivalent to a "secure erase" [sic] using hdparm(8).

Source ?

See https://linux-ide.vger.kernel.narkive.c ... sing-a-ssd

The two commands call different ATA functions but both attempt to erase all data on the drive.
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Re: [Solution not found but problem went away] Single boot:

Postby p.H » 2020-09-26 07:19

Head_on_a_Stick wrote:There is only one way to make sure that all data is erased on a solid-state device: https://www.youtube.com/watch?v=sQYPCPB1g3o

Can you please provide a short description for those like me who cannot or do not want to view videos from youtube ?
Is it about something else than physical destruction ?

Head_on_a_Stick wrote:See https://linux-ide.vger.kernel.narkive.c ... sing-a-ssd

The two commands call different ATA functions but both attempt to erase all data on the drive.

The reply states otherwise : what these two functions actually do is firmware-dependent. Also, the thread was focused on speed, not security.
When you use blkdiscard, the SSD (assuming a SATA SSD) will receive an
ATA TRIM command, whereas hdparm --security-erase will issue an ATA
SECURITY ERASE UNIT command.

What the drive then actually does is dependant on the implementation
details of that particular SSD's firmware.

In general, I would expect the performance gain from TRIMing the entire
drive to be either the same-as, or possibly less-than the gain from
SECURITY ERASE. For a sane firmware implementation I'd expect them to
have the same effect on performance. Firmware implementations are not
always sane.

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Re: [Solution not found but problem went away] Single boot:

Postby Head_on_a_Stick » 2020-09-26 08:25

p.H wrote:Can you please provide a short description for those like me who cannot or do not want to view videos from youtube ?

Oh, sorry. Better link: https://patents.google.com/patent/US20170050190A1/en

p.H wrote:Is it about something else than physical destruction ?

No.

The dd command is no more guaranteed to clear the contents of the drive than either hdparm or blkdiscard because of over-provisioning. Physical destruction is the only way to be sure.
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