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Old 01-23-2012, 11:03 PM   #1
Bubbaleone
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Default Secure HDD Erasing: UCSD/CMRR

These forums: Computer Help, and Software for Windows are regularly requested to give advice on how to securely erase a hard drive. I've replied to these querys and have also read, and agreed with, the knowledgeable replies by many other AnandTech members.

Ok,...I have been "securely" erasing HDDs for years. I've always used accepted, mainstream, disk-level, 3rd-party software for this purpose. However, after thoroughly reading all the research documentation done by UCSD/CMRR, I've reached the conclusion that a great deal of what I thought I knew on this subject is, at best, faulty.

It's faulty because I'd accepted, and believed, that both the information freely distributed by software manufacturers promoting their products, and the articles by and proclamations of "experts in the field", which have saturated the web for many years, were the truth...the facts...and nothing but the facts. I'm no longer a believer.

I think if you read for yourself what UCSD/CMRR actually does, who they do it for, and their role in international HDD design implementations, you may well reach the same conclusion. I don't claim to be an "expert" at anything. However, if anyone is an "expert" on this topic, these guys really are.

University of California, San Diego
Center for Magnetic Recording Research

Former and Current Sponsors
Website
Tutorial on Disk Drive Data Sanitization

This quote is from the last page of the tutorial:

Quote:
Computer Forensics Data Recovery

Forensics recovery uses exotic data recovery techniques by experts with advanced equipment. Its normal purpose is to recover data from failed hard disk drives, and for legal discovery. Forensic companies can successfully recover unerased but protected data in a disk drive using electronic instrumentation. However, the secure erase commands discussed above erase all user data on the disk drive beyond physical disk drive forensic recovery. Drives old enough to permit such attack are too old to have the Secure Erase built-in command.

Paranoid-level recovery concerns based on hypothetical schemes are sometimes proposed by people not experienced in actual magnetic disk recording, claiming the possibility of data recovery even after physical destruction. One computer forensics data recovery company claims to be able to read user data from a magnetic image of recorded bits on a disc, without using normal drive electronics. Reading back tracks from a disk taken out of a drive and tested on a spin stand was practical decades ago, but no longer with today’s microinch-size tracks.
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Old 01-24-2012, 10:22 AM   #2
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I think you are reading too far into it. You can read for days on end of different theories and methods and real world tests. Keep in mind, it is still a magnet writing and reading data in physical drives. Once it is overwritten it is extremely hard to recover any data.
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Old 01-25-2012, 05:36 AM   #3
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Obviously you didn't bother to actually visit UCSD/CMRR's website and read anything, or examine the freeware erasing utility they offer, which is all I suggested in my post:

Quote:
Originally Posted by Bubbaleone View Post
I think if you read for yourself what UCSD/CMRR actually does, who they do it for, and their role in international HDD design implementations, you may well reach the same conclusion....
I believe all of the following companies, who sponsor and rely upon the scientific research done by USCD/CMRR, would disagree with your statement:

Quote:
Originally Posted by Matt1970 View Post
I think you are reading too far into it. You can read for days on end of different theories and methods and real world tests. Keep in mind, it is still a magnet writing and reading data in physical drives. Once it is overwritten it is extremely hard to recover any data.
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Old 01-25-2012, 06:27 AM   #4
denis280
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the fact is. you cant erase a hd completely.
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Old 01-25-2012, 01:14 PM   #5
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Quote:
Originally Posted by Bubbaleone View Post

I believe all of the following companies, who sponsor and rely upon the scientific research done by USCD/CMRR, would disagree with your statement:
As per the Q&A on the CMRR website.

Q: Is any data left after a secure erase?

A: Investigations at CMRR at UCSD have shown that a single pass secure erase at lower frequencies results in no remaining data signals and a second erase reduces this signal only slightly more. The resulting data signal to noise ratio (SNR) at the magnetic drive head is below that required to recover data using a disk drive channel . The only recorded signal left in these experiments is a small amount of highly distorted track edge recording which is extremely difficult to recover data from even if the disk is removed from the drive and tested on a spin-stand.
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Old 01-25-2012, 02:20 PM   #6
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That information is correct only if the drive is erased using the "internal secure erase" feature. UCSD/CMRR was instrumental in the implementation of this built-in feature of HDDs manufactured since 2001.

3rd-party erasing software, and manufacturer supplied format utilities do not access the password protected, built-in, secure erase feature. The freeware utility SECUREERASE, which is available on the UCSD/CMRR site, does unlock the password protected secure erase feature: Download Freeware Secure Erase Utility

Last edited by Bubbaleone; 02-01-2012 at 04:32 AM.
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Old 03-13-2012, 06:28 AM   #7
Magic Carpet
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Quote:
HDDerase.exe is a DOS-based utility that securely erases "sanitizes" all data
on ATA hard disk drives in Intel architecture computers (PCs).
(: What about other than Intel ?
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Old 03-13-2012, 09:16 AM   #8
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Quote:
Originally Posted by Magic Carpet View Post
(: What about other than Intel ?
If you're running SPARC, PowerPC, or any other non-IBM compatible computer, that doesn't natively support DiskOperatingSystem, then obviously you can't run this utility on those machines.

However, disk drives aren't processor architecture dependent. SPARC, PowerPC, etc., use the same buses (PATA, SATA, SCSI, SAS, Fibre) that Intel based machines use. Meaning, that if you're running one of those systems and you'd like to use this utility to access the internal secure erase feature on your hard drive, you'll need to pull it out and hook it up to a PC.

Last edited by Bubbaleone; 03-13-2012 at 09:21 AM.
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Old 03-14-2012, 05:30 PM   #9
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I just lol'ed at the fact, that IBM-PC hadn't been mentioned instead.
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Old 03-14-2012, 06:33 PM   #10
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I had to think on that a bit myself..LOL. "...Intel architecture computers (PCs)" I guess it's just the author's choice of wording... if it's a "PC" it's IBM compatible.
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