Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. - Page 2

Phædrus2401 · 11-08-2009, 01:13 PM

You could simply delete all files;
You could delete and rebuild the partition table;
Or you could run DBAN or a similar disk-wiping program.

All three will work, depending on how thorough you want to be. If you want to install an operating system then I'd use the second option; personally I usually use the Linux dd command to wipe a drive when I repurpose it (does same thing as DBAN).

I don't think you ever did tell us your power supply. Overvoltage of the +5V rail could have caused an issue like yours. I had a friend who lost his RAID 0+1 array because of that; it fried two of his four hard drives, the equivalent ones in each 0 group, so he couldn't rebuild.

dh2005 · 11-08-2009, 03:56 PM

There's not really a PSU to speak of. It's in a powered USB caddy with a regular kinda power cable - I don't know the voltage. And I'm no electrician.

Regarding erasing from a drive, there won't be an OS. It'll just be a media drive. I've decided to restructure my library, and the drive that currently holds 700GB of DVD rips will now become a Blu-ray rip drive... in view of that, which option would you recommend? I'll do whatever is best.

Thanks again. So, so grateful for all the expert opinion around here.

dh2005 · 11-09-2009, 06:57 AM

I erased all the files from a 1.5TB drive just now, and it now shows 3.61GB used. Is this due to crap left behind, or is this simply the formatting?

**raptor_pa** · 11-09-2009, 07:13 AM

How did you erase? Did you format the drive?

dh2005 · 11-09-2009, 07:18 AM

No, dude. I just erased every file. That's exactly the question I'm keen to answer.

When blanking a drive (because you want to use it for something else...), is it acceptable to simply delete all the files, or is the only proper approach to reformat it?

By the way - that 3.61GB was mostly in the Recycle Bin. There's only 115MB used, now.

dh2005 · 11-09-2009, 07:32 AM

Also, if anyone's interested, the ceiling in my bathroom just collapsed...

**raptor_pa** · 11-09-2009, 07:33 AM

The best way is to zero wipe it and start over use killdisk or dban, then initialize, partition and format. Deleting and formatting only blank the records to locate the files( OK so deleting only marks them as deleted. They do nothing to the actual areas where the data was stored.

dh2005 · 11-09-2009, 07:38 AM

Right. Interesting... so, "deleting" doesn't actually delete anything?!

So, does the data that was "deleted" from a drive stay there, kinda hidden, until that part of the drive is written to again?

**raptor_pa** · 11-09-2009, 07:40 AM

Yes it does, and is easily recoverable. Deleting simply marks the sectors as available for reuse.

dh2005 · 11-09-2009, 07:48 AM

Ah haaaaaaa!!! That's interesting.

One more question, please... as a follow-up to your earlier comment, is reformatting a drive any more thorough than deleting the files, or exactly the same?

dh2005 · 11-09-2009, 08:07 AM

If someone could please answer that ASAP, I'd be really grateful. Once I know that, I can get on with restructuring my media library.

**raptor_pa** · 11-09-2009, 10:22 AM

Reformatting overwrites directory entries, but again the data remains intact. the only way to ensure the data is gone is to zero-wipe the disk, which writes to every sector ont eh drive.

dh2005 · 11-09-2009, 10:28 AM

Fair enough. I follow you.

By that reckoning, if you're going to write more data to a drive than there was on it before the delete, that would succeed in overwriting it all in any case. Right...?

Thanks for your patience with this. I reckon I'm pretty-much decided on how I'll be approaching this.

**raptor_pa** · 11-09-2009, 10:40 AM

Not necessarily, the disk does not start at sector 1 and write in order, it does random writes - altho in a general front to back way, there is no way to control it, a lot depends on the logic of the drive, the size of files being written etc. And if you just delete, the old file system is intact. Plus you also deal with file slack. File slack is particularly a concern on larger drives.
Drives are broken down into 512 byte sectors. The OS references a group of sectors as a cluster - a cluster size of say 8kb would be 16 sectors. A Cluster is the smallest element the OS can use to store a file. So if the file is sat a 20 byte text file, on disk it would still occupy an 8 KB cluster. If there had been a previous file occupying that space that was deleted, only the first 20 bytes of that file would be overwritten, the remianinf 8 kb of data would still be in the slack space. The OS will ignore it because it sees the end of file marker for the active file, but the data is there, and accessible.
Bottom line if you are repurposing the drive, a zero wipe is the best way, it is the slowest, but it also has the advantage of allowing the drives internal programming to remap any bad sectors to good spares. This remapping only occurs on a write operation, so writing to all sectors will trigger the remapping if a bad sector is encountered.

dh2005 · 11-09-2009, 10:54 AM

Much appreciated, dude.

11-08-2009, 01:13 PM	#21 (permalink)
Phædrus2401 Hardware Tech Team Join Date: Mar 2009 Location: New Orleans Posts: 3,782 OS: Vista Ultimate x64 SP1 + Ubuntu 9.04 My System	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. You could simply delete all files; You could delete and rebuild the partition table; Or you could run DBAN or a similar disk-wiping program. All three will work, depending on how thorough you want to be. If you want to install an operating system then I'd use the second option; personally I usually use the Linux dd command to wipe a drive when I repurpose it (does same thing as DBAN). I don't think you ever did tell us your power supply. Overvoltage of the +5V rail could have caused an issue like yours. I had a friend who lost his RAID 0+1 array because of that; it fried two of his four hard drives, the equivalent ones in each 0 group, so he couldn't rebuild. __________________ Good PSU brands: Corsair, SeaSonic, CWT, PC Power and Cooling, Thermaltake Toughpower, CoolerMaster Real Power Pro On 80+ Certification - PSU Information and Selection - Power Supply Myths You don't get what you don't pay for.

11-08-2009, 03:56 PM	#22 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. There's not really a PSU to speak of. It's in a powered USB caddy with a regular kinda power cable - I don't know the voltage. And I'm no electrician. Regarding erasing from a drive, there won't be an OS. It'll just be a media drive. I've decided to restructure my library, and the drive that currently holds 700GB of DVD rips will now become a Blu-ray rip drive... in view of that, which option would you recommend? I'll do whatever is best. Thanks again. So, so grateful for all the expert opinion around here.

11-09-2009, 06:57 AM	#23 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. I erased all the files from a 1.5TB drive just now, and it now shows 3.61GB used. Is this due to crap left behind, or is this simply the formatting?

11-09-2009, 07:13 AM	#24 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,812 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. How did you erase? Did you format the drive? __________________

11-09-2009, 07:18 AM	#25 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. No, dude. I just erased every file. That's exactly the question I'm keen to answer. When blanking a drive (because you want to use it for something else...), is it acceptable to simply delete all the files, or is the only proper approach to reformat it? By the way - that 3.61GB was mostly in the Recycle Bin. There's only 115MB used, now. Last edited by dh2005; 11-09-2009 at 07:32 AM.

11-09-2009, 07:32 AM	#26 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Also, if anyone's interested, the ceiling in my bathroom just collapsed...

11-09-2009, 07:33 AM	#27 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,812 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. The best way is to zero wipe it and start over use killdisk or dban, then initialize, partition and format. Deleting and formatting only blank the records to locate the files( OK so deleting only marks them as deleted. They do nothing to the actual areas where the data was stored. __________________

11-09-2009, 07:38 AM	#28 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Right. Interesting... so, "deleting" doesn't actually delete anything?! So, does the data that was "deleted" from a drive stay there, kinda hidden, until that part of the drive is written to again?

11-09-2009, 07:40 AM	#29 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,812 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Yes it does, and is easily recoverable. Deleting simply marks the sectors as available for reuse. __________________

11-09-2009, 07:48 AM	#30 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Ah haaaaaaa!!! That's interesting. One more question, please... as a follow-up to your earlier comment, is reformatting a drive any more thorough than deleting the files, or exactly the same?

11-09-2009, 08:07 AM	#31 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. If someone could please answer that ASAP, I'd be really grateful. Once I know that, I can get on with restructuring my media library.

11-09-2009, 10:22 AM	#32 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,812 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Reformatting overwrites directory entries, but again the data remains intact. the only way to ensure the data is gone is to zero-wipe the disk, which writes to every sector ont eh drive. __________________

11-09-2009, 10:28 AM	#33 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Fair enough. I follow you. By that reckoning, if you're going to write more data to a drive than there was on it before the delete, that would succeed in overwriting it all in any case. Right...? Thanks for your patience with this. I reckon I'm pretty-much decided on how I'll be approaching this.

11-09-2009, 10:40 AM	#34 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,812 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Not necessarily, the disk does not start at sector 1 and write in order, it does random writes - altho in a general front to back way, there is no way to control it, a lot depends on the logic of the drive, the size of files being written etc. And if you just delete, the old file system is intact. Plus you also deal with file slack. File slack is particularly a concern on larger drives. Drives are broken down into 512 byte sectors. The OS references a group of sectors as a cluster - a cluster size of say 8kb would be 16 sectors. A Cluster is the smallest element the OS can use to store a file. So if the file is sat a 20 byte text file, on disk it would still occupy an 8 KB cluster. If there had been a previous file occupying that space that was deleted, only the first 20 bytes of that file would be overwritten, the remianinf 8 kb of data would still be in the slack space. The OS will ignore it because it sees the end of file marker for the active file, but the data is there, and accessible. Bottom line if you are repurposing the drive, a zero wipe is the best way, it is the slowest, but it also has the advantage of allowing the drives internal programming to remap any bad sectors to good spares. This remapping only occurs on a write operation, so writing to all sectors will trigger the remapping if a bad sector is encountered. __________________

11-09-2009, 10:54 AM	#35 (permalink)
dh2005 Registered User Join Date: Nov 2009 Posts: 23 OS: XP	Re: Western Digital Caviar Green 1.5TB... new member needs help urgently. Much appreciated, dude.