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Hard drive experiments



 
 
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  #1  
Old July 9th 19, 02:56 AM posted to alt.comp.hardware
philo
external usenet poster
 
Posts: 1,288
Default Hard drive experiments

Now that I'm an old retired guy I am finally getting around to doing a
few things I've always wanted to try concerning hard drives.

I mentioned in another thread that I had two drives taken out by a PSU
that failed.


I had all data backed up but wanted to see if switching out the
controller board might make the drives usable.

They were both WD 500G drives but I really did not want to buy one or
two more just for the sake of experimenting.

I do have a WD 320 drive with a controller that has the same part number
on it but was not sure if that would work.


As it turns out I found a WD 80G drive and a WD 120 gig drive that have
the same controller number and I swapped them...and each worked!


So I figured the controller from the 320G drive might work in the 500G


It did not however. That leads me to beleive that more has failed on the
drive than the controller board.
  #2  
Old July 9th 19, 03:25 AM posted to alt.comp.hardware
Paul[_28_]
external usenet poster
 
Posts: 1,157
Default Hard drive experiments

philo wrote:
Now that I'm an old retired guy I am finally getting around to doing a
few things I've always wanted to try concerning hard drives.

I mentioned in another thread that I had two drives taken out by a PSU
that failed.


I had all data backed up but wanted to see if switching out the
controller board might make the drives usable.

They were both WD 500G drives but I really did not want to buy one or
two more just for the sake of experimenting.

I do have a WD 320 drive with a controller that has the same part number
on it but was not sure if that would work.


As it turns out I found a WD 80G drive and a WD 120 gig drive that have
the same controller number and I swapped them...and each worked!


So I figured the controller from the 320G drive might work in the 500G


It did not however. That leads me to beleive that more has failed on the
drive than the controller board.


The two drives just might use different density platters.

Sometimes, one drive is just a platter more than another
drive, and the controller board runs 1,2,3, or 4 platters.
That might make a good swap.

But say the 320 was a 1x320 and the 500 was a 2x250. The
metadata in the service area on the two might be different.

There are also some exceptional cases. WDC didn't want to
make any more 500GB drives. They took some 1TB drives and
"short-stroked" them in firmware. That means they certify
the whole 1TB surface, but to give the customer exactly
what they purchased, the heads only go from outer diameter
to center diameter. Never touching the hub.

Both drives have the same part number.

Now, imagine you need to do a controller swap.
The controllers are different. Quite different.

I think I might own three of those, two ordinary,
and one short stroked.

I've also seen a claim in a hard drive repair forum,
that some controllers are "branded", and if you
swap controllers, you have to transfer a small ROM
from one controller to the other. Whether this is FDE
in disguise, I don't know. There was a claim at one time,
that all drives would be Full Disk Encryption by year X,
and when that year arrived we heard... nothing. Crickets.
But that doesn't mean a drive can't be FDE and use a
private key. The owner is oblivious to the danger, until
the private key (on the controller) is lost. Transferring
the controller affords a way to lose it.

The key method is attractive, as on such drives, if
you do a Secure Erase, instead of taking two hours
and writing the entire surface, the controller
just erases the private key, *instantly* rendering
all the data on the disk as gibberish. It looks like
solid binary after that. Because without the key, the
contents are just "scrambled eggs".

Playing with hard drives is full of "what ifs".

Paul
  #3  
Old July 10th 19, 03:22 PM posted to alt.comp.hardware
philo
external usenet poster
 
Posts: 1,288
Default Hard drive experiments

On 7/8/2019 9:25 PM, Paul wrote:
philo wrote:
Now that I'm an old retired guy I am finally getting around to doing a
few things I've always wanted to try concerning hard drives.

I mentioned in another thread that I had two drives taken out by a PSU
that failed.


I had all data backed up but wanted to see if switching out the
controller board might make the drives usable.

They were both WD 500G drives but I really did not want to buy one or
two more just for the sake of experimenting.

I do have a WD 320 drive with a controller that has the same part
number on it but was not sure if that would work.


As it turns out I found a WD 80G drive and a WD 120 gig drive that
have the same controller number and I swapped them...and each worked!


So I figured the controller from the 320G drive might work in the 500G


It did not however. That leads me to beleive that more has failed on
the drive than the controller board.


The two drives just might use different density platters.

Sometimes, one drive is just a platter more than another
drive, and the controller board runs 1,2,3, or 4 platters.
That might make a good swap.

But say the 320 was a 1x320 and the 500 was a 2x250. The
metadata in the service area on the two might be different.

There are also some exceptional cases. WDC didn't want to
make any more 500GB drives. They took some 1TB drives and
"short-stroked" them in firmware. That means they certify
the whole 1TB surface, but to give the customer exactly
what they purchased, the heads only go from outer diameter
to center diameter. Never touching the hub.

Both drives have the same part number.

Now, imagine you need to do a controller swap.
The controllers are different. Quite different.

I think I might own three of those, two ordinary,
and one short stroked.

I've also seen a claim in a hard drive repair forum,
that some controllers are "branded", and if you
swap controllers, you have to transfer a small ROM
from one controller to the other. Whether this is FDE
in disguise, I don't know. There was a claim at one time,
that all drives would be Full Disk Encryption by year X,
and when that year arrived we heard... nothing. Crickets.
But that doesn't mean a drive can't be FDE and use a
private key. The owner is oblivious to the danger, until
the private key (on the controller) is lost. Transferring
the controller affords a way to lose it.

The key method is attractive, as on such drives, if
you do a Secure Erase, instead of taking two hours
and writing the entire surface, the controller
just erases the private key, *instantly* rendering
all the data on the disk as gibberish. It looks like
solid binary after that. Because without the key, the
contents are just "scrambled eggs".

Playing with hard drives is full of "what ifs".

** Paul




Well, I'm just playing that's all.


I was in the industrial battery business and know how labeling goes.

At one time a lower ampere-hour battery and changer was sometimes
identical to the next size up...other than the name plate.
  #4  
Old July 10th 19, 03:54 PM posted to alt.comp.hardware
John McGaw
external usenet poster
 
Posts: 707
Default Hard drive experiments

On 7/10/2019 10:22 AM, philo wrote:
On 7/8/2019 9:25 PM, Paul wrote:
philo wrote:
Now that I'm an old retired guy I am finally getting around to doing a
few things I've always wanted to try concerning hard drives.

I mentioned in another thread that I had two drives taken out by a PSU
that failed.


I had all data backed up but wanted to see if switching out the
controller board might make the drives usable.

They were both WD 500G drives but I really did not want to buy one or
two more just for the sake of experimenting.

I do have a WD 320 drive with a controller that has the same part number
on it but was not sure if that would work.


As it turns out I found a WD 80G drive and a WD 120 gig drive that have
the same controller number and I swapped them...and each worked!


So I figured the controller from the 320G drive might work in the 500G


It did not however. That leads me to beleive that more has failed on the
drive than the controller board.


The two drives just might use different density platters.

Sometimes, one drive is just a platter more than another
drive, and the controller board runs 1,2,3, or 4 platters.
That might make a good swap.

But say the 320 was a 1x320 and the 500 was a 2x250. The
metadata in the service area on the two might be different.

There are also some exceptional cases. WDC didn't want to
make any more 500GB drives. They took some 1TB drives and
"short-stroked" them in firmware. That means they certify
the whole 1TB surface, but to give the customer exactly
what they purchased, the heads only go from outer diameter
to center diameter. Never touching the hub.

Both drives have the same part number.

Now, imagine you need to do a controller swap.
The controllers are different. Quite different.

I think I might own three of those, two ordinary,
and one short stroked.

I've also seen a claim in a hard drive repair forum,
that some controllers are "branded", and if you
swap controllers, you have to transfer a small ROM
from one controller to the other. Whether this is FDE
in disguise, I don't know. There was a claim at one time,
that all drives would be Full Disk Encryption by year X,
and when that year arrived we heard... nothing. Crickets.
But that doesn't mean a drive can't be FDE and use a
private key. The owner is oblivious to the danger, until
the private key (on the controller) is lost. Transferring
the controller affords a way to lose it.

The key method is attractive, as on such drives, if
you do a Secure Erase, instead of taking two hours
and writing the entire surface, the controller
just erases the private key, *instantly* rendering
all the data on the disk as gibberish. It looks like
solid binary after that. Because without the key, the
contents are just "scrambled eggs".

Playing with hard drives is full of "what ifs".

*** Paul




Well, I'm just playing that's all.


I was in the industrial battery business and know how labeling goes.

At one time a lower ampere-hour battery and changer was sometimes identical
to the next size up...other than the name plate.


Yeah. Identical products with different part numbers and a range of prices
-- all because some had longer warranty periods covered by the higher cost.
  #5  
Old July 11th 19, 02:55 AM posted to alt.comp.hardware
philo
external usenet poster
 
Posts: 1,288
Default Hard drive experiments

On 7/10/19 9:54 AM, John McGaw wrote:
On 7/10/2019 10:22 AM, philo wrote:
On 7/8/2019 9:25 PM, Paul wrote:
philo wrote:
Now that I'm an old retired guy I am finally getting around to doing
a few things I've always wanted to try concerning hard drives.

I mentioned in another thread that I had two drives taken out by a
PSU that failed.


I had all data backed up but wanted to see if switching out the
controller board might make the drives usable.

They were both WD 500G drives but I really did not want to buy one
or two more just for the sake of experimenting.

I do have a WD 320 drive with a controller that has the same part
number on it but was not sure if that would work.


As it turns out I found a WD 80G drive and a WD 120 gig drive that
have the same controller number and I swapped them...and each worked!


So I figured the controller from the 320G drive might work in the 500G


It did not however. That leads me to beleive that more has failed on
the drive than the controller board.

The two drives just might use different density platters.

Sometimes, one drive is just a platter more than another
drive, and the controller board runs 1,2,3, or 4 platters.
That might make a good swap.

But say the 320 was a 1x320 and the 500 was a 2x250. The
metadata in the service area on the two might be different.

There are also some exceptional cases. WDC didn't want to
make any more 500GB drives. They took some 1TB drives and
"short-stroked" them in firmware. That means they certify
the whole 1TB surface, but to give the customer exactly
what they purchased, the heads only go from outer diameter
to center diameter. Never touching the hub.

Both drives have the same part number.

Now, imagine you need to do a controller swap.
The controllers are different. Quite different.

I think I might own three of those, two ordinary,
and one short stroked.

I've also seen a claim in a hard drive repair forum,
that some controllers are "branded", and if you
swap controllers, you have to transfer a small ROM
from one controller to the other. Whether this is FDE
in disguise, I don't know. There was a claim at one time,
that all drives would be Full Disk Encryption by year X,
and when that year arrived we heard... nothing. Crickets.
But that doesn't mean a drive can't be FDE and use a
private key. The owner is oblivious to the danger, until
the private key (on the controller) is lost. Transferring
the controller affords a way to lose it.

The key method is attractive, as on such drives, if
you do a Secure Erase, instead of taking two hours
and writing the entire surface, the controller
just erases the private key, *instantly* rendering
all the data on the disk as gibberish. It looks like
solid binary after that. Because without the key, the
contents are just "scrambled eggs".

Playing with hard drives is full of "what ifs".

*** Paul




Well, I'm just playing that's all.


I was in the industrial battery business and know how labeling goes.

At one time a lower ampere-hour battery and changer was sometimes
identical to the next size up...other than the name plate.


Yeah. Identical products with different part numbers and a range of
prices -- all because some had longer warranty periods covered by the
higher cost.




Yes.

Now after I've been retired I see the logic.
 




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