Wiping a hard drive

Topic

New Reply

I recently hooked up all my external drives. They were partitioned. So, I moved all the files I wanted to my TB drive. The drives are small, one 80GB, one 120GB and two 160GB drives. I deleted the partitions, did a quick format then am using CCleaner to overwrite with 3 passes. This takes hours to do. Still got about 12hrs on a 120GB drive.

Got the 160GB drive yet to go. Question is, if I do only 1 pass but then repeat 3 times, is that equal to the 3x pass?

Am looking to donate these drives once wiped. So I want everything clean before donating.

BTW, did download/burn dban but it won’t boot on my system (went into the bios and there’s no option to boot from cd). That’s why I’m using CCleaner.

TIA

Reply | Quote

Replies

My guess it that it may not be equvalent since the first pass may be identical each time, while a successive three pass is probably using a variable overwrite pattern from pass to pass.

Reply | Quote

My guess it that it may not be equvalent since the first pass may be identical each time, while a successive three pass is probably using a variable overwrite pattern from pass to pass.

So I guess I’ll go the slow route. Thanks

Reply | Quote

Modern hard drives only need one pass with random data to securely wipe – this assumes you want to protect your data from a government agency.
To clean them so you can pass them on you only need to delete the partition, create a new one and format.

cheers, Paul

Reply | Quote

BTW, did download/burn dban but it won’t boot on my system (went into the bios and there’s no option to boot from cd).

That would be extremely surprising!
Have you tried pressing F12 or F8 every few seconds when booting, to come up with a “From which device do you want to boot?” screen?

BATcher

Plethora means a lot to me.

Reply | Quote

There should be a BIOS option to set the boot order where you can make the CD/DVD first in the list.

Jerry

Reply | Quote

There should be a BIOS option to set the boot order where you can make the CD/DVD first in the list.

Jerry

I looked in the BIOS but wasn’t sure. I see a setting for USB CD. Settings in the BIOS on my old box were much clearer.

Reply | Quote

From what I’ve read recently, the comonly accepted best practice is to first encrypt the drive, and then erase fill once with random data. Use TrueCrypt, or any good free encryption program, with the longest password allowed, consisting of random, upper and lower case letters, numbers and special characters. No need to remember the password, since you will never be decrypting it. Good Luck.

Reply | Quote

How can Windows be installed on a computer that cannot Boot from a CD ?

Reply | Quote

Usually from a USB device.

Reply | Quote

who are you afraid of ?

wiping wont stop the cia kgb mossad from reading them

in the 50s we used to drill holes in them and then run them through a crusher
recovery ability is even better today

if you want to reuse them then bulk erase and do a low level format

what is the value of an old HD anyway ?

i would go with the physical destruction if you are worried about the data being read
otherwise just bite the bullet and let the program run like it was designed

i suspect 3x 1 pass is not 1x 3 pass as they do not use the same pass each time when they repeat
and why would that be any faster ? you still read/write the same volume of data

Reply | Quote

who are you afraid of ?

wiping wont stop the cia kgb mossad from reading them

in the 50s we used to drill holes in them and then run them through a crusher
recovery ability is even better today

if you want to reuse them then bulk erase and do a low level format

what is the value of an old HD anyway ?

i would go with the physical destruction if you are worried about the data being read
otherwise just bite the bullet and let the program run like it was designed

i suspect 3x 1 pass is not 1x 3 pass as they do not use the same pass each time when they repeat
and why would that be any faster ? you still read/write the same volume of data

I don’t plan on me reusing the drives. If I were, I would’ve just removed the partitions and reformatted. I plan on giving these drives away. Yes they are older (IDE), but are in good shape. Someone should be able to get some use out of them.

The only drive I’m keeping is the 300GB drive, the smaller ones are going, going, gone.

Anyhow, the wiping is done. 3x overwrite and had a fan blowing on the drives to keep them cool.

If I had wanted to destroy the drives, I have a pretty good sized hammer and would’ve beaten them flat.

Reply | Quote

the smaller ones are going, going, gone.

Then just drill a hole through them or hit them a couple of times with a sledge. Or just toss them in with your trash. No one, unless they are into misery, will want a drive less than 320 GB. Such drives are not worth the trouble as new drives can be had for less than $50.00, are newer and probably operate better.

Paranoia about cleaning drives is absurd when there is probably nothing worth attempting to recover on your drives. A simple FDISK, repartition and format will remove the data from all but the most persistent of people. Such people are not going to waste time on finding out your bank account only has $4.00 left. People that are going to go through such effort are looking for passwords for major system access and corporate secrets.

Reply | Quote

There is an easier way – encrypt the drive and then just wipe it using a 1x setting. A 1x pass should be enough for a drive used on a home computer.

Read this article:

File and folder encryption and data erasure: The best and most secure way to erase the data on a hard disk drive or solid state drive (SSD) –

http://www.pcbuyerbeware.co.uk/The-best-way-to-erase-the-data-on-a-hard-drive-and-ssd.htm

Reply | Quote

Being an Old School tech of 30+ years, I do what I’ve always done, when I want to clean a hard drive, block out any bad sectors and set at least one partition.

I boot up with my DOS Utilities boot disk, then run FDISK to remove all existing partitions and create ONE new one.
Then I use the DOS Format command to format the disk. That writes to every sector on the disk to verify its integrity, thus erasing any date that may have been stored there. Any sectors that do not pass the test are blocked out so they will never be used again.
(every hard drive has a ‘Bad Sector Map’ which lists the address of every bad sector, so they will never be used)

After the partitioning and formatting, the drive is clean and ready for whatever I want to do with it.

Old School, YES, but also very effective!

Cheers Mates!
The Doctor 😎

Reply | Quote

effective for average folks

but still the cia mossad and kgb can still read it

the only sure way is physical destruction

what is the value of an old HD anyway?
just trash it if security is an issue

Reply | Quote

what is the value of an old HD anyway?

The value of that HD in the context of this sub-discussion (begun in post 16 above) is the value of the computer to be donated (which would be useless without a disk in it). That poster seems to have considered this value (to people who otherwise might not have access to a computer at all) sufficient to be willing to put at least limited effort into cleaning it (presumably because as a business machine it could have had moderately sensitive data on it, else why bother?).

Reply | Quote

but still the cia mossad and kgb can still read it

Anyone can read the data unless you actually wipe the disk or overwrite it another way – see post 13 – which is bill’s point.
Re-installing the OS from scratch overwrites a large portion of the data making recovery very difficult or impossible, depending on what data was stored on the disk in the first place.

cheers, Paul

Reply | Quote

Re-installing the OS from scratch overwrites a large portion of the data making recovery very difficult or impossible, depending on what data was stored on the disk in the first place.

The problem with that theory is that a great deal of what gets over-written when one reinstalls the OS is just the old OS, not the user’s data. Even if the old OS was subject to sufficient patch activity that much of it was replaced, NTFS tends to try to avoid medium-to-large file fragmentation by using up a fair amount of the disk’s contiguous free space before re-using space that has been freed up by deletions, so – especially with today’s disks which tend to be MUCH larger than the OS alone requires – a large percentage of a user’s data will typically still be present and scavengeable on the drive after OS reinstallation.

And then there’s the page file, little of which actually gets written during a reinstallation – so if the reinstallation places it in the same location that the original installation did most of the contents of the old version will be scavengeable as well (though making sense out of that content may be more of a challenge than any casual snoop would bother with). Ditto any hibernation file.

There’s certainly a continuum of paranoia that ranges from none at all (hey, why would anyone bother looking, anyway? just give away the disk as-is…) to ridiculous (sledge-hammers and annealing furnaces). But given how easy it is to over-write all the content of a disk once (2 to 3 unattended hours per TB – just reinstalling the OS takes a noticeable percentage of that time, plus requires a fair amount of user interaction while doing it) it seems kind of a no-brainer.

Reply | Quote

Multiple pass myth.

cheers, Paul

Reply | Quote

I want to take a office computer and let Residents at our complex use it.
How do I safely accomplish this?
I know a little about computers, but nothing like some of the stuff I’ve read.
You can send me a source, say Wiping a Computer for Dummies and I’d really be happy.
thanks,
cj2013

Reply | Quote

You need to install Windows / *nix from scratch, deleting any existing partitions in the process. This will remove all the previous files and leave you with a fresh, ready to go computer.
Note: Windows PCs have a sticker with the license info. You need a Windows install disk that matches the license type, usually the manufacturers installation / recovery CD.

cheers, Paul

Reply | Quote

You need to install Windows / *nix from scratch, deleting any existing partitions in the process. This will remove all the previous files and leave you with a fresh, ready to go computer.

I don’t believe that’s true at all, unless you occupy the entire disk with partitions and perform a full format (not a ‘quick format’) on each in a manner that actually overwrites every sector on the disk with new data (or use the ‘secure erase’ firmware function present on most contemporary disks).

Otherwise, any space not used by the new Windows or Unix installation (including spare space in the partition to which the operating system is installed) will retain whatever data from cj2013’s office may have occupied that region – and that data will be readable using easily-available (often free) data recovery applications that can scavenge it even if the high-level partition and file structure under which it was originally written has been replaced by a new one.

The ease with which such scavenging can be performed even after repartitioning and quick formating is why anyone with potentially sensitive data on a disk wipes it before giving it away – though as described in this thread a single wiping pass writing random data (and perhaps even just zeros) should be sufficient to deter any such casual (and perhaps even fairly serious) scavenging attempts.

Reply | Quote

Yes, not wiping the disk leaves the data readable with specialised software, but this is an old office computer for use by residents, not an ex-military computer being sent overseas.

cheers, Paul

Reply | Quote

Yes, not wiping the disk leaves the data readable with specialised software, but this is an old office computer for use by residents, not an ex-military computer being sent overseas.

That seems a rather casual attitude to take toward someone else’s business data when they’ve asked for advice about how to protect it. Whether potentially leaving such data readily accessible on it (via applications which anyone can readily find on the Internet, often obtain for free, and use nearly as easily as Windows Explorer) is appropriate is a matter for cj to decide – and your casual allegation that “This will remove all the previous files and leave you with a fresh, ready to go computer” seemed likely to be misleading to someone who ‘knows little about computers’. The precautions I described should be considered minimal for anyone concerned about privacy, let alone possible financial or other harm: suggesting that only those with military secrets to protect need do so is preposterous.

Reply | Quote

bill, I assume you shred your paper and the burn it, otherwise someone might spend hours reconstructing it. 🙂

cheers, Paul

Reply | Quote

bill, I assume you shred your paper and the burn it, otherwise someone might spend hours reconstructing it

You may (or may not) know the common observation about assumptions, Paul. As a matter of fact, I shred virtually nothing. However, I AM quite careful about ‘assuming’ that other people are equally cavalier about such behavior, especially when offering advice they have asked for – a practice which you might consider adopting yourself.

Reply | Quote

It wasn’t a business computer. But, I did have stuff on there that I’d rather not have anyone else access what I moved off. Don’t think they’d be interested in my porn collection either. :p

I also had text files with addresses/phone numbers, login details for numerous groups/forums. Plus personal photos. No need for that stuff to get out there.

Reply | Quote

It wasn’t a business computer.[/quote]

Actually, ‘it’ was: I explicitly referred to post 16 as the origin of this sub-discussion.

But, I did have stuff on there that I’d rather not have anyone else access what I moved off. Don’t think they’d be interested in my porn collection either. :p

I also had text files with addresses/phone numbers, login details for numerous groups/forums. Plus personal photos. No need for that stuff to get out there.

Indeed. If I ever do get rid of a disk drive (I’ve had what may have been miraculously good luck for the past 25 years: I tend to keep old machines that still run around for nostalgia’s sake, and the couple of drives which have actually failed have failed in a manner that doesn’t allow wiping them so I’ve kept them around too) it will have been wiped at least once or, if that’s not possible, physically rendered incapable of running (though I’m not really worried about someone caring enough to shell out for electron microscopy or even going through the process of replacing the circuit board with a functional one).

It’s worth mentioning that similar considerations apply to things we might throw out without thinking (flash media, for example, which pretty much need to be destroyed if not effectively wiped by a complete deletion followed by a complete TRIM or by being completely filled with random data – TrueCrypt can do a good job with that with reasonable speed), unless one knows that nothing sensitive has ever been placed there (as might typically be the case with floppies which tended to be too small ever to have had anything significantly sensitive on them).

Reply | Quote

Would doing a format as a part of the reinstallation solve some or most of this problem? I know in my case if I am installing a new OS, or reinstalling an OS from scratch, I commonly will format after choosing Custom Install. This seems to give me a more pristine installation. Of course I’m generally not doing this to sell or give the PC away although I have in the past.

The last time I sold a PC (8 or 9 year old or so Dell XPS desktop) I deleted all personal data, then formatted as part of reinstallation of Win 7 to give the new owners a clean installation. The new owner was buying a machine that his adolescent son could use to play games on.

Reply | Quote

Format these days usually defaults to the quick variety, so only the file allocation tables are re-created. The data remains unless you perform a full disk format – which would be slower than overwriting just the existing data.

cheers, Paul

Reply | Quote

There are also unformat programs available that will handle full format as well. That said, I wouldn’t lose any sleep over the procedure Ted use with a personal PC although I personally would wipe the disk first since it doesn’t cost anything but unattended time as Bill said. I would definitely use a disk wipe program with a business PC.

Jerry

Reply | Quote

There are also unformat programs available that will handle full format as well

A full format that includes formatting empty space cannot be undone. Modern hard disks do not allow recovery of data from overwritten sectors.

cheers, Paul

Reply | Quote

If I want to erase the entire hard drive (before discarding the computer), is it possible to run “Erase” from a USB stick?

J

Reply | Quote

Shred it: http://www.youtube.com/watch?v=2mtgZruckc4

Reply | Quote

Easus claims to be able recover from a full format. From: http://www.easeus.com/landing/unformat.htm?gclid=CNOz5qKrjLgCFc9AMgodYwoApQ
“EaseUS Data Recovery Wizard is a user-friendly and straightforward format recovery solution to unformat files from quick or full formatted drive for Windows”

Haven’t tried it myself so I don’t know how effective it is.

Jerry

Reply | Quote

For those persons capable of being able to perform a low-level format, which is NOT the standard format offered by DOS or Windows, generally four or more passes will render the media unreadable to most publicly available forensic softwares out there, however, reading of low magnetic levels and over-written magnetic media has come a long way over the past decade and can be decoded with a high degree of reliability for most sectors using the more sophisticated forensics. The day of “wiping a disk” is almost over if interest is severe. Rotation has to be rendered impossible so sync in the firmware can not be accomplished. Merely putting holes in the media will only obscure the data in the media area actually damaged by the hole(s), the disc can still be spun up and read in all other areas. Remove top cover, smash each platter into at least three pieces will render it secure. Almost anything less leaves holes in your strategy to be completely secure. Altering, renewing partitions to secure or obscure data is a myth. Partitions are not required nor needed to read the media data. Single overwriting merely leaves a stronger signal over top of a weaker one which will, using the current algorythms, produce data which can be recovered.

Reply | Quote

Dban – mentioned earlier in the thread would be a solution, I believe. See http://www.dban.org/. Though it says to burn to a CD, it may well work on a USB stick, but I’ve not tried it. I would just say that teh software helped me recover a disk that had been screwed by a power outage (I think the MBR had been corrupted). I couldn’t even put Linux on it, but after running Dban on it, I was able to install Linux (the PC was running XP – very slowly!).

Eliminate spare time: start programming PowerShell

Reply | Quote