So, data recovery isn't your main. You didn't invest on Tools (head replacement tools, clean room, PC3000,donors, R&D.....etc).
How could you judge on others if you are not working on a real data recovery business?

Take your pills and go to bed...

I have proved my point.



Good night.

I notice that WD/HGST is using the same PCB design for both its SATA and SAS models. I wonder if the kernel code is the same, in which case it may be possible to use the SAS PCB + SATA ROM for data recovery.



I'm also wondering what additional hardware (other than a piezo transducer) could be responsible for the increased pin count in the HDA connector (28 pins).

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A backup a day keeps DR away.

I think no, because SoC will be switched to SATA mode by the ROM and SAS interface is not compatible with it.

Newer drives have humidity sensor inside.
This particular drive also has Helium sensor(no idea how it works)

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How new is "newer"?

I did some investigating in the following thread:

Helium level sensors - where/what are they?
viewtopic.php?f=1&t=35770

Seagate claims that "except for a low accuracy thermistor for temperature measurement, the HGST helium drive has no digital environmental sensors".

A WD patent explains how a cheap thermistor can be calibrated to monitor the helium level.

Seagate states that its helium drives use "high-accuracy digital MEMS sensors for measuring temperature, pressure and relative humidity."

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A backup a day keeps DR away.

I'm also curious about the helium drive at the following site.

Seagate IronWolf Pro 12TB HDD Review | KitGuru (helium):

https://www.kitguru.net/components/hard-drives/simon-crisp/seagate-ironwolf-pro-12tb-hdd-review/2/
https://www.kitguru.net/wp-content/uploads/2017/11/Seagate-Ironwolf-12TB-Hard-Drive-Review-on-KitGuru-PCB.jpg

Its HDA connector (J2) has 28-pins whereas Seagate's ST8000AS0002 air drive has 24 (J4). The air drive has 2 differential pairs (read and write channel) while the helium drive has 4 such pairs. Does anyone have any idea what is going on inside this helium drive? AFAIK, Seagate's dual actuator drives have not yet hit the market.

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A backup a day keeps DR away.

Are we talking about the same thing?

SATA HDA + SATA ROM + SAS PCB <--> SATA HBA

Could this combination negotiate a link?

SAS HDA + SAS ROM + SATA PCB <--> SAS HBA

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A backup a day keeps DR away.

4-year old Seagates(like Crawford) have them, IDK about other drives

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Could be 2D-recording. I think Seagate have those already.

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So that would suggest that each head has 3 read elements and 1 write element, yet Seagate's documents talk about 2 read heads. :?

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A backup a day keeps DR away.

Well, usually people say "thank you" but you can have it you way.

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I don't understand why my observation has put your nose out of joint. Of course I'm grateful for any information. I'm simply pointing out that your explanation is inconsistent with Seagate's "documentation", as sparse as it is. That said, I believe you are probably correct, so either there are 3 read elements per head (as published in at least one patent), or there is an extra differential pair whose function is unknown to us.

BTW, I don't understand why Seagate would need a humidity sensor in a "sealed-in helium environment". Perhaps that's another error in the documentation?

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A backup a day keeps DR away.

Perhaps to detect, whether that environment is still sealed and not broken?
(I don't know, but I guess reversing the firmware and taking a look what it does in the firmware with the results of that sensor might help)

The KitGuru review makes no mention of TDMR in respect of the 12TB IronWolf drive, nor do Seagate's datasheet or product manual.

https://www.seagate.com/www-content/product-content/ironwolf/en-us/docs/100818527d.pdf
https://www.seagate.com/www-content/datasheets/pdfs/ironwolf-12tbDS1904-9-1707US-en_US.pdf

However, the new 14TB Exos is being promoted as a TDMR drive.

I found this Seagate patent to be helpful:

Multi-sensor data transducer:
http://patentimages.storage.googleapis.com/pdfs/US20150043098.pdf


AISI, true TDMR is when data are being retrieved from two or more tracks at the same time. This would imply that the transfer rate should double, all else being equal. However, the sustained transfer rate for the IronWolf is 210MB/s which is no better than earlier models.

Therefore, ISTM that the 3-lane read channel is decoding only a single track of data, but is using all 3 read elements for tighter track positioning. If so, then is this really "TDMR"?

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A backup a day keeps DR away.

Both 10TB and 12TB Helium Seagate models use two preamps inside, that's why so many wires.
But why they use it's a guess work, could be TDMW or could be something else.

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Do you have any references that we could read?

I'm wondering what sort of output one would get from a head test via terminal. Shorting the read channel would be interesting, too.

I'm assuming that these drives would support recent ATA commands which enable an end user to see the "PhysicalElementStatus". I'm wondering whether such commands would report the status of each read element or each head?

All SeaChest Utilities User Guides:
http://support.seagate.com/seachest/SeaChest_Combo_UserGuides.html

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A backup a day keeps DR away.

I don't have any public references

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I don't understand marketing people. ISTM that, if your product has a unique feature that sets it apart from its competitors, then you should promote it.

BTW, I notice that several "air drives" from WD and Seagate have barometric pressure sensors, but you won't see this in any of their public docs.

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A backup a day keeps DR away.