What if you opened your HDD...

[Pariah]

1/3 the height of a finger print? I find that hard to believe, sure a human hair but not a finger print...

I take that comment back. I was actually way off. The flying height of a typical hard drive head today is less than .5 microinches (1 millionth of an inch), while a fingerprint has the height of about 620 microinches meaning the read head height is about 1/1300th as high, not 1/3. A typical human hair is 2000 microinches wide, or more than 4000 times thicker than the read head flying height. Needless to say, a modern hard drive is quite a feat of high tech engineering.

How small is a microinch?

 

[Philippine Mango]

Originally posted by: JDCentral

Originally posted by: Philippine Mango

1/3 the height of a finger print? I find that hard to believe, sure a human hair but not a finger print...

Why? It's a glass platter with a film sprayed onto it...
And they go through A LOT of effort to get this very, very, very, very smooth.

the platters aren't made of glass.... Maybe new HDDs but all the OLD hdds i've opened, had steel platters.

 

[ShadowBlade]

window mod guide http://www.casemodgod.com/cmg/Howto-story--45.html

 

[Concillian]

Originally posted by: Philippine Mango
the platters aren't made of glass.... Maybe new HDDs but all the OLD hdds i've opened, had steel platters.

WOW. Lots of misinformation in this thread. Platters that are not glass are aluminum, and have been for at least as long as I've worked in the industry (7 years). Glass is widening in it's usage, but I'm willing to bet the majority of all hard drive platters are still aluminum. Glass platters may not look like glass without close inspection because they have metal films deposited onto them. They will probably be slightly transparent when looking at longtudinal media. Not as sure about perpendicular media, as the film thicknesses involved are significantly higher.

Pariah seems to have the most correct information.

Fly height is indeed on the order of 0.5 microinches (can't get specific because of proprietary information issues, let's just say 0.5 ± 0.5... for reference 1 microinch = 254 angstroms). And that is DAMN close. He is also correct that you won't be able to reliably flip bits without an electromagnet.

If you DO flip bits, you will do so independent of whether they are formatting and servo bits or whether they are data bits. So you would very likely ruin the ability to use the HD. Once the servo information is gone, the drive is toast, it can't stay on track and can't etsimate actuator accelerations and decellerations needed to reliably seek.

Humidity is as good a substitute for a cleanroom as you can do in normal environment, I think. Dust becomes a site for steam to form into water, and water forms around the dust, it then starts sticking to colder surfaces. This reduces the amount of dust in the air. The secondary advantage is that static electricity issues are a lesser concern. Static isn't a huge issue when dealing with platters, but with heads, it's a HUGE issue. Your best bet is to use a slightly warm drive (refer to MFR specs for how warm is too warm), to open it in a humid room, and to minimize exposure

Platter surfaces are indeed very smooth and quite flat as well.

Edit:
Obviously I'm not advocating opening your drive, nor should any of this be interpreted as speaking for my employer.

 

[Philippine Mango]

Originally posted by: Concillian

Originally posted by: Philippine Mango
the platters aren't made of glass.... Maybe new HDDs but all the OLD hdds i've opened, had steel platters.

WOW. Lots of misinformation in this thread. Platters that are not glass are aluminum, and have been for at least as long as I've worked in the industry (7 years). Glass is widening in it's usage, but I'm willing to bet the majority of all hard drive platters are still aluminum. Glass platters may not look like glass without close inspection because they have metal films deposited onto them. They will probably be slightly transparent when looking at longtudinal media. Not as sure about perpendicular media, as the film thicknesses involved are significantly higher.

Pariah seems to have the most correct information.

Fly height is indeed on the order of 0.5 microinches (can't get specific because of proprietary information issues, let's just say 0.5 ± 0.5... for reference 1 microinch = 254 angstroms). And that is DAMN close. He is also correct that you won't be able to reliably flip bits without an electromagnet.

If you DO flip bits, you will do so independent of whether they are formatting and servo bits or whether they are data bits. So you would very likely ruin the ability to use the HD. Once the servo information is gone, the drive is toast, it can't stay on track and can't etsimate actuator accelerations and decellerations needed to reliably seek.

Humidity is as good a substitute for a cleanroom as you can do in normal environment, I think. Dust becomes a site for steam to form into water, and water forms around the dust, it then starts sticking to colder surfaces. This reduces the amount of dust in the air. The secondary advantage is that static electricity issues are a lesser concern. Static isn't a huge issue when dealing with platters, but with heads, it's a HUGE issue. Your best bet is to use a slightly warm drive (refer to MFR specs for how warm is too warm), to open it in a humid room, and to minimize exposure

Platter surfaces are indeed very smooth and quite flat as well.

Edit:
Obviously I'm not advocating opening your drive, nor should any of this be interpreted as speaking for my employer.

Yea I meant that they were metal and not glass. Glass for platters has only recently become more widely used.

 

[Pariah]

No, it hasn't. Glass has been used in mobile drives since the 90's. IBM has been using them in their desktop models since the 75GXP released way back in 2000.

 

[Philippine Mango]

Originally posted by: Pariah
No, it hasn't. Glass has been used in mobile drives since the 90's. IBM has been using them in their desktop models since the 75GXP released way back in 2000.

2000 isn't that long ago...

 

[Pariah]

5 years is an eternity in the computer industry. 5 years ago predates the Pentium 4, with the buzz in the industry being Intel and AMD announcing 1 GHz CPU's. Also, the original GeForce was king of the graphics world, and 3dfx and Matrox were still viable desktop options.

 

[Philippine Mango]

Originally posted by: Pariah
5 years is an eternity in the computer industry. 5 years ago predates the Pentium 4, with the buzz in the industry being Intel and AMD announcing 1 GHz CPU's. Also, the original GeForce was king of the graphics world, and 3dfx and Matrox were still viable desktop options.

Um no, the P4 was around in 2000...

 

[Pariah]

I said 5 years ago. Which is a long time. The P4 was released in late November of 2000, that's less than 5 years ago. The 75GXP was available in May of 2000, which is more than 5 years ago, and a full 6 months before the P4.

Anything else you want to incorrectly try to correct?

 

[Jeff7]

Originally posted by: Pariah
I said 5 years ago. Which is a long time. The P4 was released in late November of 2000, that's less than 5 years ago. The 75GXP was available in May of 2000, which is more than 5 years ago, and a full 6 months before the P4.

Anything else you want to incorrectly try to correct?

Technically speaking, all he said was "Um no, the P4 was around in 2000... " which is correct.


However, in context, it doesn't quite fit.