Well I admit. I am a super panaroid person who feared being hacked. Privacy is the top priority for me.

You are right, I want to be absolute sure to delete because I might be considering to change my PC within 3 years. SO let's learn enough skills before I really sell it.
Let's assume everything was in the default since the installation typically goes from default settings. (And being applicable to most readers.) Thanks for asking it!

Ok- so the wikipedia trying to say that a simple hacker who knows how to undelete file will end up a failure other than an experienced one, with super skills? (About 60% or 80% failure to recover rate? :? )

Thanks for your reply. When I mean that above, I mean the full 300GB, not a 4 or above small partitios despite anyone could do it and save time (That is caches,confidental data stored on 1 or at most 2 small partition with no more than 1 GB and encrypt it on files that are not related to internet browsing) .

I've always had an interest in computer security as far back as I can remember (I was attempting to reverse engineer Windows executables by the age of 8)...but when my wife and I were victims of identity theft a couple of years back (used a weak password on ebay and paypal), it went from "hobby" to "lifelong focus". I'll freely admit that many times I go overboard with security, but there's a reason for it =)

Harddisks are magnetic. Maybe ext3 deletes it in a way that it might not be accessible from a computer anymore, but how about analog data recovery? You know there are companies that can read some of your data even after the harddisk has burned. A german company was asked to restore the data on the harddisks of the WTC after 9/11...

Maybe that's the trick of secure deleting by going over your data for about 20 times.

You could just shred the harddrive and then reinstall the operating system or you could just keep the computer

The last time I had a hard drive crash (difficulty mounting, made "click"ing sounds), just for fun I completely disassembled it down to the last screw. I couldn't help notice that the read-write arms are held between 2 strong magnets. As one of my co-workers put it: "Powered by the very thing that can destroy it." The platters, though, are quite solid and difficult to physically damage. I laid one on a concrete garage floor and used a ball-peen hammer to pound dents into it until the smooth coating cracked and began to flake off. For another one, I squeezed in a bench vice and bent it back and forth. Then turned it 90 degrees and did the same thing. It didn't snap, but it had a nice + shaped crease and the coating was pretty well-destroyed. For the third one, I used a knife to carve the word BAD into it in large letters and then stuck it to a metal shelf using both of the "super" magnets that accompanied it. Security wasn't the aim here. I just wanted to find out how easy/hard it is to damage the platters.

When you do replace the computer you can always keep the same hard drive as a master if it has the OS and drivers for the new hardware on it, or as a slave, or buy a USB enclosure and use it as an external disk.

You seem to have touched on yet another area where Linux outshines Windows...with a generic kernel build, you can typically move a hard drive with Linux on it between machines with relatively little hassle...the same can be done with Windows, but it's much a much hairier experience and typically requires re-activation haha.

Good point, though...if security/privacy are a huge concern, why give the hard drive away to begin with?

That's why LiveCDs are such a great universal troubleshooting tool!

Even before XP and M$'s gestapo tactics, I remember moving a Win98 disk from one machine to another. If I didn't have the install CD it wouldn't have worked. It always has, and always will, annoy me how many times it has to reboot itself when installing hardware drivers or software that includes background daemons. And if the new machine had drive letters arranged differently, for example if apps were previously installed on D and were now on E or F, the apps had to be reinstalled. I don't remember if 9x had a logical disk manager but it was years later, when working with 2000 in a classroom, before I found out that it can be used to reassign drive letters.

Having to get M$'s permission to reactivate Windows after all of that so I can use it more than 50 times on the new hardware would certainly be a breaking point for me. I had to help a friend once do just that and it was not a pleasant experience: ~2 hours on the phone waiting to speak to a human that will read you the secret code that sounds like he's making it up with a cereal box decoder pin.

on attack of the show they put cd's in the microwave for 10 seconds as a cheaper alternative to buying a paper shredder capable of handling vinyl cd's (the sparks that flew off of the cd's was a cool bonus).

here is my horrible experience with trying to install windows from a non-oem cd:
......

I think that when someone would take Ubuntu, remastered it with the XPDE GUI, added samba support out of the box, included a future version of mono and wine and the Kubuntu 7.04 installer people would suddenly like Linux instead of Windows because:
1) Installs faster
2) no need for seperate driver installs
3) no virusses and other crap

At least to me, this explains that:
1) Windows is worth nothing
2) Windows lovers don't even know shit about computers
3) Microsoft is a failure

If The UNIX Time-Sharing System* D. M. Ritchie and K. Thompson isn't you're idea of great American literature, you don't belong here.

BTW this is the first thing a new linux user should read to learn about their new OS. It's the ultimate "Getting Started" guide. If you memorize this document, your whole life will be 10x easier. It's not all that much to read either but pound for pound it's the most powerful knowledge you can get about the system, especially troubleshooting one.

It was written in 1973 or so but it's almost all still the same... you know like we are on AMD/Intel instead of pdp-11s and have 2GB memory instead of 768k :P

-Viz

^^ Actually contrary to how many books have been written, i find that simply just getting your hands wet is the best way to learn anything. memorizing any document shouldn't be just all the knowledge you know, some of it should be experience, since you remmeber more of what you did then what a book will tell you that you read 5 years ago.