Hard Drive Erase Utilities - Question

[MACDRIVE]

If I use a hard drive erase CD like Wipe Drive or one of the other brands, is the hard drive usable afterwards? Inotherwords, if I wipe the drive completely clean, can I then go and reload the operating system?

Which brand of hard drive erase utility would you guys recommend?

 

[todd2000]

To answer your first question, yes you can reuse the drive, but you don't need a seperate Utility to wipe the drive, Disk Utility can do it for you. If I understand you correctly you wan't to securly erase all the data on your hard drive right? If so just Open Disk Utility, highlight the disk, click the Erase tab, then the Security Options Button on the bottom, and you will get 4 options

Don't Erase Data - This erases the directory structure, but leaves the data intact, not very secure.

Zero Out Data - Writes 0s over all the data more secure, but not compleatly

7-Pass Erase - Very secure option writes data over disk 7 times, but it will tak e while. I believe this is Government level security.

32-Pass Erase - Extreamly secure writes data 32 times, but will take a LOOOOOOOONNNGGG TIME.

I would go with the Zero, or 7 times. click ok, and then click erase and your good to go.

 

[MACDRIVE]

What you have mentioned above would work great if I was running 10.4, but I'm running 10.3. The 'Options' and 'Erase' buttons are both "grayed out" at the bottom of the window. Of course I don't know why.

I was just trying to regain some lost HD storage. I have a 80Gb drive with only 74.4Gb capacity of which 72Gb is "Free". I'm assuming that at the beginning of an install, I should have the full 80Gb capacity before the drive gets formated.

Thanks for your reply Todd.

 

[DZ/015]

There was a discussion recently about advertised and realized hard drive space. Should answer all of your space questions.

The reason those options are greyed out in disk utility is that you are trying to erase your start up volume. To do this, you need to start from your install cd or dvd. You cannot erase your start up volume with your start up volume.

 

[janey]

You cannot erase your start up volume with your start up volume.

su
rm -rf /

would do it. However, I don't know how far you'd get before rm tries to delete the rm program itself.

I was just trying to regain some lost HD storage. I have a 80Gb drive with only 74.4Gb capacity of which 72Gb is "Free". I'm assuming that at the beginning of an install, I should have the full 80Gb capacity before the drive gets formated.

Hard drive manufacturers report 1 GB as being 10^9 (1,000,000,000 bytes) and your computer reports 1 GB as being 2^30 (1,073,741,824 bytes). The difference in bytes (73,741,824 bytes, which is about 70.3mb per GB) is why it's 74.4GB and not 80GB.
70.3mb * 80 (gb on your drive) = 5626.1mb difference, which is roughly just a bit over 5.5GB.
80GB - 5.5GB = 74.5GB
The 0.1GB (74.5-74.4) difference could be attributed to how your drive was formatted, data about the drive and how it's formatted would take up space. The rest would be for OS X to use.

 

[JFreak]

I would go with the Zero, or 7 times.

Zeroing hard drive is more than secure enough for regular people with regular secrets I can not imagine such a file on my personal computer that I should delete formatting my hard drive seven times, let alone 32

 

[motulist]

What about bad blocks? I've heard that if you wipe a disk using most normal formatting tools that it doesn't overwrite the information in the areas that are reported as bad blocks, so that a group with enough desire, resources and skill could extricate some data from those blocks. I don't know if it's a myth or not and I doubt you're wiping anything that is sensitive enough to warrant being concerned about this, but for the sake of comprehensiveness the question should be raised.

 

[JFreak]

What about bad blocks? I've heard that if you wipe a disk using most normal formatting tools that it doesn't overwrite the information in the areas that are reported as bad blocks, so that a group with enough desire, resources and skill could extricate some data from those blocks.

If the disk has one bad block that supposedly has "sensitive data", then how much would that one partial block be worth of? If everything else but one block is wiped clean, who would say what data it is?

 

[motulist]

A block usually encompasses several bytes, as I understand it. Several bytes is more than enough data to make you insecure if it happens to be a block that contains something sensitive. For instance it could contains some plain text that says "kill president Bu" . Not to even mention that several bad blocks may be contiguous. I'm not saying it's anything to be worried about in the real world, but for the sake of being totally comprehensive it deserves a mention.

 

[janey]

i think blocks in HFS+ are more like 512 bytes by default.

 

[rjmccorkle]

can this be done to erase a disc over the network? i wanna 32-pass my crappy lappy vaio that ran windows and sell it.