Seagate BarraCuda Platter Filling Order

[kangarootaco]

Does anyone know the order in which the platters of a Seagate BarraCuda ST3000DM007 are filled in Windows, assuming a single maximum partition? Also, are they filled from inside to outside?

Thanks

[Lardman]

Why not just tell us what the second dr lab have told you, on track wasn't it.

[kangarootaco]

Why not just tell us what the second dr lab have told you, on track wasn't it.

I've updated the thread.

I'm asking the question because it is only the most recently saved files that I need from the patient drive, and if there's a chance that those are all going to a platter that wasn't damaged, then it might be worth sending it somewhere else for one more evaluation.

[fzabkar]

The drive writes 100 tracks, say, on head 0, then switches to head 1 and writes 100 more tracks, then 100 tracks on head 2, and back to head 0 for the next 100 tracks, and so on.

This "serpentine" tracking is described here:

https://hddscan.com/doc/HDD_Tracks_and_Zones.html

[terminator2]

The drive writes 100 tracks, say, on head 0, then switches to head 1 and writes 100 more tracks, then 100 tracks on head 2, and back to head 0 for the next 100 tracks, and so on.

This "serpentine" tracking is described here:

https://hddscan.com/doc/HDD_Tracks_and_Zones.html

Thanks fzabkar for this important post.
I would like to know more about how selectively heads write like -
1) At start which head out of many reads SA and firmware - If it is damaged then what
2) After how many tracks head switches - if it is 100 tracks for 10TB disk then heads will be violently change so fast they might wear out fast.
3) Any video showing hows heads and platters are synchronised -how single file is divided across many platters and how different heads read same file.
This will be helpful in situations where I blindly disable heads in DE so files covered by disabled heads get corrupted due to missing sectors. I can better update customers as how this mechanisam works
Thanks aagain

[lcoughey]

Seagate Grenada headmaps can be all over the place. I've seen some where one head starts with 1 or 2 random sectors in before switching , while other heads have hundreds or thousands. Then there are the cases where the start sector isn't even head 0.

At the end of the day, each case is different and the only way to know if the required file is recoverable is to get the drive reading enough to image the good surfaces and hope that you can also get lucky and get enough of the file table to even know where the files are stored.

I find such cases only useful when customers are just looking for photos.

[Doomer]

1) At start which head out of many reads SA and firmware - If it is damaged then what

On Seagate drives SA is on logical heads 0 and 1, and sometimes (rarely) on logical H2 (but not on Barracuda drives).
"Logical head" is important here, if a Seagate drive has the very bottom head present (which is physical H0) then very likely the number(index) of physical and logical heads are the same, otherwise you need to keep in mind that physical and logical head number might not be the same

2) After how many tracks head switches - if it is 100 tracks for 10TB disk then heads will be violently change so fast they might wear out fast.

it really depends on the drive, if you can give us full model number and the PN then some of us here might be able to be more specific

3) Any video showing hows heads and platters are synchronised -how single file is divided across many platters and how different heads read same file.

the files are written by the file system driver, and the file system driver has no clue about where in the drive it writes, it has no idea that the drive has heads and how many, or any clue about the serpentine writing, so there is no relation between a file and a physical head.
However, linear file writing will in general follow the serpentine file writing on most of the Seagate drives

[terminator2]

1) At start which head out of many reads SA and firmware - If it is damaged then what

On Seagate drives SA is on logical heads 0 and 1, and sometimes (rarely) on logical H2 (but not on Barracuda drives).
"Logical head" is important here, if a Seagate drive has the very bottom head present (which is physical H0) then very likely the number(index) of physical and logical heads are the same, otherwise you need to keep in mind that physical and logical head number might not be the same

2) After how many tracks head switches - if it is 100 tracks for 10TB disk then heads will be violently change so fast they might wear out fast.

it really depends on the drive, if you can give us full model number and the PN then some of us here might be able to be more specific

3) Any video showing hows heads and platters are synchronised -how single file is divided across many platters and how different heads read same file.

the files are written by the file system driver, and the file system driver has no clue about where in the drive it writes, it has no idea that the drive has heads and how many, or any clue about the serpentine writing, so there is no relation between a file and a physical head.
However, linear file writing will in general follow the serpentine file writing on most of the Seagate drives

Finally last words have came from world's most authoritative person for Seagate Drives ( I am wondering whether seagate might not be knowing many secrets / flaws which Doomer , pepe and others including fzabkar know)
Appreciate your technical skills ,dedication and focus.
Thanks for sharing this information.
I was absolutely not aware following -
1) Physical and logical heads are different. I get this option in UDMA which heads to select often I select physical Don't know whether it is right or wrong.
2) Head 0 numbering starts with bottom platter.
3) If any seagate drive has bottom head then both logical and physical heads are same
I still dont know difference between physical and logical heads as all I know that disk has read write heads physically present.
In udma I always disable some heads if they give lots of bad sectors or reading errors.Let me confess I grossly ignore root cause of errors which might be in FW or defect list etc.
Thanks again

[Doomer]

I still dont know difference between physical and logical heads as all I know that disk has read write heads physically present.

Physical heads are the heads that are physically present on the HSA.
Logical heads always starts from 0 and and are always consecutive. The drive uses logical heads to read any data from tracks.

for example

Code:

PH LH
0 -> 0
1 -> 1
2 -> 2
3 -> 3


or

Code:

PH LH
1 -> 0
3 -> 1
4 -> 2
5 -> 3


[terminator2]

I still dont know difference between physical and logical heads as all I know that disk has read write heads physically present.

Physical heads are the heads that are physically present on the HSA.
Logical heads always starts from 0 and and are always consecutive. The drive uses logical heads to read any data from tracks.

for example

Code:

PH LH
0 -> 0
1 -> 1
2 -> 2
3 -> 3


or

Code:

PH LH
1 -> 0
3 -> 1
4 -> 2
5 -> 3


Thanks .But I haven't understood anything yet.I will dig deeper.

[terminator2]

You might want to read this :

http://www.hddoracle.com/viewtopic.php?f=46&t=1402

Thanks Spildit
I haven't seen so comprehensive and well compiled post .It has covered everything. It will take lots of time for me to digest this. I have just downloaded hddoracle for offline browsing .Its sort of HDD wikipidia.

[labtech]

I still dont know difference between physical and logical heads as all I know that disk has read write heads physically present.

Physical heads are the heads that are physically present on the HSA.
Logical heads always starts from 0 and and are always consecutive. The drive uses logical heads to read any data from tracks.

for example

Code:

PH LH
0 -> 0
1 -> 1
2 -> 2
3 -> 3


or

Code:

PH LH
1 -> 0
3 -> 1
4 -> 2
5 -> 3


Thanks .But I haven't understood anything yet.I will dig deeper.

@terminator2
On drives with no missing/deactivated heads, as on the 4 heads drive example above 0,1, 2, 3, the physical heads map will be consecutive from the bottom: Head 0, Head 1, Head 2 and Head 3. Therefore, the software tool (Data Extractor) will create a logical map that will match the physical heads map exactly.

On drives that have missing/deactivated heads, using the physical head map example above of 1,3,4,5, it means head 0 and head 2 are physically missing/deactivated. As a result, Data Extractor won't reflect those missing heads, so in the logical map, the heads will be shifted. So, logical head 0 will be the first logical head, matching physical head 1, as that is the first active physical head. And so on.

It would be nice if Data Extractor could VISUALLY match the logical map to the physical map exactly even with those odd maps, but they are not programmed that way. Not sure if it is even possible, as programming is not my strength.

[terminator2]

I still dont know difference between physical and logical heads as all I know that disk has read write heads physically present.

Physical heads are the heads that are physically present on the HSA.
Logical heads always starts from 0 and and are always consecutive. The drive uses logical heads to read any data from tracks.

for example

Code:

PH LH
0 -> 0
1 -> 1
2 -> 2
3 -> 3


or

Code:

PH LH
1 -> 0
3 -> 1
4 -> 2
5 -> 3


Thanks .But I haven't understood anything yet.I will dig deeper.

@terminator2
On drives with no missing/deactivated heads, as on the 4 heads drive example above 0,1, 2, 3, the physical heads map will be consecutive from the bottom: Head 0, Head 1, Head 2 and Head 3. Therefore, the software tool (Data Extractor) will create a logical map that will match the physical heads map exactly.

On drives that have missing/deactivated heads, using the physical head map example above of 1,3,4,5, it means head 0 and head 2 are physically missing/deactivated. As a result, Data Extractor won't reflect those missing heads, so in the logical map, the heads will be shifted. So, logical head 0 will be the first logical head, matching physical head 1, as that is the first active physical head. And so on.

It would be nice if Data Extractor could VISUALLY match the logical map to the physical map exactly even with those odd maps, but they are not programmed that way. Not sure if it is even possible, as programming is not my strength.

Nicely explained and well understood. Thanks a lot
I would like to know which heads (physical or logical) to select in DE when it asks for selection. Will that matter in results ?

[higgsboson]

I still dont know difference between physical and logical heads as all I know that disk has read write heads physically present.

Physical heads are the heads that are physically present on the HSA.
Logical heads always starts from 0 and and are always consecutive. The drive uses logical heads to read any data from tracks.

for example

Code:

PH LH
0 -> 0
1 -> 1
2 -> 2
3 -> 3


or

Code:

PH LH
1 -> 0
3 -> 1
4 -> 2
5 -> 3


Thanks .But I haven't understood anything yet.I will dig deeper.

@terminator2
On drives with no missing/deactivated heads, as on the 4 heads drive example above 0,1, 2, 3, the physical heads map will be consecutive from the bottom: Head 0, Head 1, Head 2 and Head 3. Therefore, the software tool (Data Extractor) will create a logical map that will match the physical heads map exactly.

On drives that have missing/deactivated heads, using the physical head map example above of 1,3,4,5, it means head 0 and head 2 are physically missing/deactivated. As a result, Data Extractor won't reflect those missing heads, so in the logical map, the heads will be shifted. So, logical head 0 will be the first logical head, matching physical head 1, as that is the first active physical head. And so on.

It would be nice if Data Extractor could VISUALLY match the logical map to the physical map exactly even with those odd maps, but they are not programmed that way. Not sure if it is even possible, as programming is not my strength.

Thanks .Is that Means for normal hard disks (non deactivated disks) Physical Heads should be selected in DE and for missing deactivated cases logical heads ?

[labtech]

Thanks .Is that Means for normal hard disks (non deactivated disks) Physical Heads should be selected in DE and for missing deactivated cases logical heads ?

Please, could you show a photo of this window asking you to select physical or logical? I think you are probably referring to something else, not building a heads map.

[terminator2]

Thanks .Is that Means for normal hard disks (non deactivated disks) Physical Heads should be selected in DE and for missing deactivated cases logical heads ?

Please, could you show a photo of this window asking you to select physical or logical? I think you are probably referring to something else, not building a heads map.

Oh yes labtech. I also feel so. I will update snapshot of the window which I am referring to.
Thanks a lot