Unused HardDrive space

[lucrioual]

Was reading around the other day and found this:
http://www.theinquirer.net/?article=14597

I've read several things from people saying that they have gotten more space out of it and I was wondering if anyone here has. A lot of people are saying that all its doing is overlapping space which wouldn't be a good thing cause then you will get corruption. I jsut want to see if anyone has done it before I try to do it with my spare drive

-Thanks

 

[airfoil]

Interesting, but its from March 9th?

 

[blurredvision]

I remember seeing this article from a while back. There is a thread elsewhere here on Anandtech about this, but not sure where. I never wanted to take the time to try it out, as I have a hard enough time figuring out what to fill up my 200GB hdd with anyhow.

 

[DaveSimmons]

HardOCP.com had a couple of follows on it, as I recall results were not good. You might use Advanced Search here and whatever search HardOCP has to read more.

Logic dictates that it did not work reliably, or we would still be talking about it.

 

[iwantanewcomputer]

if there's a will there's a way
i think a lot of drives have a platter that is only half used(one side and not the other)
for example, i'm pretty sure there are 2 platters and thus 4 sides in the seagate 120 and 160 drives. the 120 has three sides full and one empty. there might be some way to unlock this...seems logical

 

[DaveSimmons]

From the follow-up letters:

am the "Linux SATA guy".

First, users are usually amused to learn that the capacity of modern hard drives is _unknown_, until it goes through the factory's qualification tests. The 120GB hard drive you purchased may have been physically identical to a 250GB hard drive, but simply it only passed qualification at 120GB.

Intel does the same thing with processors. A 3.0Ghz processor may be sold as 2.4Ghz, simply because it didn't pass qualification at 3.0Ghz but did at a lower clock speed.

Second, in the ATA standard there is a feature known as the "host protected area". This area is accessible from any OS -- but it requires special ATA commands in order to make this area available to the OS.

Third, all hard drives reserve a certain amount of free space to use for reallocation of bad sectors. These "spare sectors" are free space on your drive... completely unused until your hard drive starts finding problems on the physical media.

So this is old news Although the host-protected area (HPA) can be used for insidious purposes such as DRM/CPRM that is completely hidden from the users, most of the "invisible free space" exists for a purpose -- either it's spare sectors for bad sector remapping, or its capacity that didn't pass factory qualification, that you don't want to use anyway.

Feel free to edit/reproduce/publish this email.

Jeff Garzik

Not speaking for my employer, speaking as an Open Source guy

In other words, this is drive space overclocking, using platter sides that failed factory testing, and/or space that the drive needs for silently remapping "weak" sectors in the main storage. Unlocking this storage seems pretty risky.

 

[lucrioual]

yea, thanks for the comments on it
id try it out with my other drive, but from what i've heard from other people i can mess it up big time

 

[zephyrprime]

Originally posted by: iwantanewcomputer
if there's a will there's a way
i think a lot of drives have a platter that is only half used(one side and not the other)
for example, i'm pretty sure there are 2 platters and thus 4 sides in the seagate 120 and 160 drives. the 120 has three sides full and one empty. there might be some way to unlock this...seems logical

This technique is different than that. What you speak of can't be done because the drive lacks a head for that side of the platter.

....but, some drives aren't even using a full platter. There were some successful modifications done on some drives using the old IBM feature tool. I've always thought that the XBOX hard drive would be a prime candidate for this because I think the drive on a new xbox should be packing 40GB platters.

 

[VirtualLarry]

LOL at the original article. Clearly, all that they are doing is creating some sort of erroneous, overlapping partition-table scheme. If someone actually tries that, they are just asking for severe data-corruption, much of which may be difficult to detect until some later date, at which point it's probably too late to recover the orginal data, because it has already been overwritten.

zephyrprime's idea is a good one, and the only legitimate method of "capacity reclamation" for an IDE/ATA HD. There exists a feature to set a "soft LBA capacity limit" on ATA HDs. Now, on the vast majority (99%, at least), as shipped from the factory, that value is set to the same as the "LBA max limit". But on some drives, mostly on ones shipped for application-specific purposes with fixed capacity limits, they may be "soft clipped" to the desired target size, even though the actual drive has a larger physical capacity. I have likewise heard of this happening sometimes when obtaining a returned newer RMA drive in place of the sent older one. In many cases, because of the general trend of increasing HD capacities, they may send a newer drive, that has been "soft clipped" to the limit of the older one.

As far as "reclaiming" entire unused HD platters, that's highly unlikely, because to save mfg costs, they generally don't "finish" the other side of the platter, and/or don't mount a head for it. Fixing that is far beyond the capability of anyone but a drive factory.

Edit: This is actually a useful feature, btw. HDs from different mfg's, or even the same (but slightly different model), can have slightly different max LBA counts, for the same general size in GB. When setting up a software/firmware RAID, generally, most will not function unless all of the drives are the same size. If you build a RAID array with 120GB drives, and one fails, and then later you purchase a slightly-different replacement HD, it could have a slightly-lower LBA count, and not function in your array.

The solution to this is, before the array is ever set up, to manually "soft clip" all of the drives that are going to be used in the array, to a nice round LBA count number, somewhat lower than the maximum of your drives. That way, in the future, if you need to replace a drive, you can also soft-clip that new drive to the same LBA count as the drives in the existing array.

(This should really be in some sort of best-practices IDE RAID FAQ, if it isn't already.)

 

[Abhi]

Wonder if this ll work on an old 1 gb HDD ...