Access openings in HDDs

[Tom Del Rosso]

Some HDDs have rather large (1cm) holes covered by plastic and foil
stickers. They seem to be positioned for easy access to destroying the
platters with a screwdriver or something. Is that what it's for?

 

[VanguardLH]

Some HDDs have rather large (1cm) holes covered by plastic and foil
stickers. They seem to be positioned for easy access to destroying the
platters with a screwdriver or something. Is that what it's for?

Filtered breather hole used to equalize air pressure inside and out. If
the platters were exposed when you remove the foil cover, there would be
no protection from contamination which would destroy them. You won't
get past the filter.

http://www.smarthdd.com/en/filters.htm
http://alasir.com/books/hards/022-024.html
http://www.datarecoverytools.co.uk/...-circulation-and-air-filtration-of-hard-disk/

http://www.techarp.com/review/Seagate/Momentus_5400.2/breather_hole.jpg
http://www.techarp.com/review/Seagate/Barracuda_7200.8/breather_hole.jpg
http://twimgs.com/networkcomputing/2012/9/howard0921.png

If you want to prevent most physical recovery methods of a hard disk,
get a drill bit and bore through the case at several places, or get a
3-lb sledge and bash it to pieces (wear eye protection). If the
platters don't shatter, use a torch to warp them or put into a vise and
bend/snap with pliers. Discard some of the [pieces of] platters in one
trash bin one week and wait until next week to dispose of the remaining
[pieces of] platters.

 

[Tom Del Rosso]

Filtered breather hole used to equalize air pressure inside and out.
If the platters were exposed when you remove the foil cover, there
would be no protection from contamination which would destroy them.
You won't get past the filter.

The holes I'm talking about are not filtered and the foil stickers covering
them are not porous.

 

[VanguardLH]

The holes I'm talking about are not filtered and the foil stickers covering
them are not porous.

There is a protective layer to prevent "accidental" intrusion of
prod-like rods into the opening. This is similar to the obstrusion in
the fuel intake tube in your car. The both prevent something going in
that's not supposed to.

If you look at the pics provided already, you won't see the filters by
looking into the holes.

http://www.pcguide.com/ref/hdd/op/packAir-c.html

You still don't see the filter there, either. You see a protective
covering and a perforated grill underneath that prevent entry of rods
into the hole. Some have discs covering the hole and the air escapes
around the disc so you can't see directly into the case to see the
filter underneath. You might see a black center in the hole and that
could very well be the filter. Filters don't have to be white and they
don't have to be soft fiber. It could be a compressed sponge of porous
metal through which gasses can seep but not the much larger sized solid
contaminants. Do the following look to you like a soft fibrous filter?
Your dentist would much appreciate your attempt to chew on these
filters. You won't be sticking a screwdriver through them, either.

http://ecx.images-amazon.com/images/I/61nu2q28K6L._SL500_AA300_.jpg
http://i01.i.aliimg.com/photo/v5/391176279/Powder_sintering_bronze_filter_disc.jpg

http://www.patentgenius.com/patent/7046469.html (click on pics)
I can't tell you if this design ever got implemented but it illustrates
how there is no direct path into the hole to reach the platters.

http://www.gore.com/en_xx/products/filtration/diskdrive/adsorbent/adsorbent_breather.html
Here is a disc-style breather filter. All you'll see through the hole
is the porous PTFE disc plate.

While some microfilters can trap particles down to 0.01 microns and
ultrafilters down to 0.001 microns, a water molecule is a third smaller
at only 0.0003 microns and why an HDD's insides can get wet by letting
in vaporous or liquid water. The breather hole is to equalize a
gradual and small change in barometric pressure, not to accomodate a
major blast through the port.

There is nothing in the HDD's case that is going to grant easy access to
the platters, like simply sticking some rod into a hole. If you don't
think it's a breather hole (barometric orifice) then take a snapshot and
put it online to give a URL to the pic so others can see what you see.

 

[Tom Del Rosso]

There is a protective layer to prevent "accidental" intrusion of
prod-like rods into the opening. This is similar to the obstrusion in
the fuel intake tube in your car. The both prevent something going in
that's not supposed to.

If you look at the pics provided already, you won't see the filters by
looking into the holes.

http://www.pcguide.com/ref/hdd/op/packAir-c.html

I'm not describing anything like that. I know about the filtered vents for
air pressure. These holes are huge by comparison, and are not porous.

For example on a WD3200AAJB the 2mm vent hole is clearly on the top side.
It is not remotely similar to the other holes. On the edge there is a large
1x0.5cm opening covered by non-porous plastic-coated foil. Peel it off and
you could stick a screwdriver in there and crack the platters, or don't peel
it and just shove the tool through the foil. This drive has a larger hole
on the bottom, partially obscured by the board, right next to the spindle so
you could use it the same way.

A similar hole is on the top side of a 2.5" drive which I already threw
away.

 

[VanguardLH]

I'm not describing anything like that. I know about the filtered vents for
air pressure. These holes are huge by comparison, and are not porous.

For example on a WD3200AAJB the 2mm vent hole is clearly on the top side.
It is not remotely similar to the other holes. On the edge there is a large
1x0.5cm opening covered by non-porous plastic-coated foil. Peel it off and
you could stick a screwdriver in there and crack the platters, or don't peel
it and just shove the tool through the foil. This drive has a larger hole
on the bottom, partially obscured by the board, right next to the spindle so
you could use it the same way.

A similar hole is on the top side of a 2.5" drive which I already threw
away.

Have yet to see what you describe where you can peer into a hole to see
the platters, head mechanism, or anything inside the drive. Are these
perhaps refurbished or rebuilt drives? Don't why they'd drill a hole to
rebuild, though. Are these holes in the center of the drive where would
be the hub and spindle?

 

[Tom Del Rosso]

Have yet to see what you describe where you can peer into a hole to
see the platters, head mechanism, or anything inside the drive. Are
these perhaps refurbished or rebuilt drives? Don't why they'd drill
a hole to rebuild, though. Are these holes in the center of the
drive where would be the hub and spindle?

No, these are unmodified.

Not the center, because it couldn't be where the spindle is.

 

[Tom Del Rosso]

Sorry I can't answer the question, but since people don't seem to
understand what you are talking about:
Many disk drives have a hole in the long side of the frame that is
covered with a plastic-and-foil sticker.

If you remove this sticker, you can see the platters and the arms
between the platters.

That's it.

I assumed the openings were for some manufacturing requirement to
see what is happening in the drive, but I have no idea what the
actual use is. (In other words, I don't think the opening is
for repair access.)

Maybe they are for some kind of testing, but they seem perfect for
destruction.

I doubt the holes are for testing because any manufacturer testing would be
done before the cover is on.

The holes can't be for anything like data recovery because they only give
access to a few sides of the platters, and little else.

Drilling holes and smashing or warping the platters won't stop
someone really, Really, REALLY, interested in the data.
Data density is probably more than 1E5 bits/inch linearly and 1E3
bits/inch crosswise, so a piece 0.01 inches on a side could have more
than 1000 bits on each of 10 tracks. Putting the pieces back together
isn't the issue; rather the issue is that an individual piece can have
useful information. So, your data isn't safe until you make the
about byte size.

Has anyone ever made a device to read fragments? I doubt it, exept maybe
the NSA has experimented with the idea. They would probably find it not
worth the effort.

 

[Robert Nichols]

Some HDDs have rather large (1cm) holes covered by plastic and foil
stickers. They seem to be positioned for easy access to destroying the
platters with a screwdriver or something. Is that what it's for?

The holes are there for controlling the arm movement during the true
low-level formatting performed in a clean room at the factory. The only
means the drive has for precisely controlling arm motion by itself comes
from the servo patterns embedded in the tracks. Prior to the writing of
the tracks during a factory low-level formatting, the drive cannot
accurately determine its own head position and is dependent on external
equipment (laser interferometer) for that function.

 

[Tom Del Rosso]

The holes are there for controlling the arm movement during the true
low-level formatting performed in a clean room at the factory. The
only means the drive has for precisely controlling arm motion by
itself comes from the servo patterns embedded in the tracks. Prior to
the writing of the tracks during a factory low-level formatting, the
drive cannot accurately determine its own head position and is
dependent on external equipment (laser interferometer) for that
function.

Thanks. That makes sense.

The formatting would be done on only 1 side, so that explains why the holes
don't allow access to all sides.

Do drives still use an entire side for servo patterns like they did when
voice coils were new?

 

[Tom Del Rosso]

Thanks. That makes sense.

The formatting would be done on only 1 side, so that explains why the
holes don't allow access to all sides.

Oops. I didn't realize at first that the drive is doing the writing and the
hole is only for position sensing.

 

[Rod Speed]

Thanks. That makes sense.

The formatting would be done on only 1 side, so that explains why the
holes don't allow access to all sides.

Do drives still use an entire side for servo patterns like they did when
voice coils were new?

Nope, no one does it that way anymore.

 

[Franc Zabkar]

For example on a WD3200AAJB the 2mm vent hole is clearly on the top side.
It is not remotely similar to the other holes.

On the edge there is a large
1x0.5cm opening covered by non-porous plastic-coated foil. Peel it off and
you could stick a screwdriver in there and crack the platters, or don't peel
it and just shove the tool through the foil.

I know that data recovery professionals will examine this foil for
evidence of a head crash. This is because the BB and JB drives have a
head stack which is anchored to the top cover by a cover screw. If you
simply remove the cover and reinstall it, you will disturb the
"alignment" of the head stack, necessitating a very laborious
realignment process. Therefore the pros try to avoid removing the
cover on these models.

This drive has a larger hole
on the bottom, partially obscured by the board, right next to the spindle so
you could use it the same way.

As already stated by RN, some drives have a hole that provides access
for the push pin of a servo writer. This is required to lay down the
servo tracks on blank discs during manufacturing. The push pin
positions the head stack.

A similar hole is on the top side of a 2.5" drive which I already threw
away.

The following article identifies and discusses the internal components
of a Seagate drive:
http://hddscan.com/doc/HDD_from_inside.html

- Franc Zabkar

 

[Arno]

Some HDDs have rather large (1cm) holes covered by plastic and foil
stickers. They seem to be positioned for easy access to destroying the
platters with a screwdriver or something. Is that what it's for?

No. Modern HDDs cannot low-level format themselves with
regard to the servo tracks. These openings serve to insert
the formatting heads. And yes, they go straight inside.

Arno

 

[Arno]

The holes are there for controlling the arm movement during the true
low-level formatting performed in a clean room at the factory. The only
means the drive has for precisely controlling arm motion by itself comes
from the servo patterns embedded in the tracks. Prior to the writing of
the tracks during a factory low-level formatting, the drive cannot
accurately determine its own head position and is dependent on external
equipment (laser interferometer) for that function.

Hmm. I also thought the servo tracks are smaller than normal
data tracks, so they need special heads to be written. At least
I saw a photograph with servo and normal tracks a while ago
that indicated this. May be outdated by now with the current
densities.

Arno

 

[Tom Del Rosso]

No. Modern HDDs cannot low-level format themselves with
regard to the servo tracks. These openings serve to insert
the formatting heads. And yes, they go straight inside.

Is the formatting on one side only, with alternating data and formatting
tracks?

Why don't they do it before the cover is on, instead of having a vulnerable
spot that could be accidentally punctured? I suppose many drives are done
that way because they have no holes.

 

[Franc Zabkar]

I know that data recovery professionals will examine this foil for
evidence of a head crash.

Just to clarify, the pros look for black debris on the foil's exposed
adhesive. I don't believe they use the opening in the case as an
inspection hole, but I could be wrong.

- Franc Zabkar

 

[Franc Zabkar]

Hmm. I also thought the servo tracks are smaller than normal
data tracks, so they need special heads to be written.

The following article should explain it:

HDD from inside: Tracks and Zones. How hard it can be?
http://hddscan.com/doc/HDD_Tracks_and_Zones.html

- Franc Zabkar

 

[Franc Zabkar]

Is the formatting on one side only, with alternating data and formatting
tracks?

Why don't they do it before the cover is on, instead of having a vulnerable
spot that could be accidentally punctured? I suppose many drives are done
that way because they have no holes.

The following articles state that servo track writers (STW) are
characterised as either external or internal devices, and the
positioning can be either internal or external, plus the discs can
either be blank or can have temporary prerecorded servo positioning
information.

http://www.fujitsu.com/downloads/MAG/vol42-1/paper11.pdf
http://www.fujitsu.com/downloads/MAG/vol37-2/paper13.pdf

- Franc Zabkar

 

[Rod Speed]

Hmm. I also thought the servo tracks are smaller than normal
data tracks, so they need special heads to be written. At least
I saw a photograph with servo and normal tracks a while ago
that indicated this. May be outdated by now with the current
densities.

Yeah, its been embedded servos entirely for a hell of a long time now.