I get a lot of Seagate drives with a bad head. Grenada and Rosewoods are the most common. Can someone explain the mechanics of why a bad head on these drives will read say the first 5% or 10% of the drive without errors (albeit slowly), but after that you get read errors, and the further into the drive you get, the head cannot read at all.

With the drive spinning faster at the start of the drive (outer tracks), in my mind I would have expected the head to read the end of the drive (inner tracks) more easily. But, I guess the angle of the head changes as the HSA moves inward and this is the cause?

I've seen instances where Grenada heads with this problem were cleaned in an ultrasonic cleaner to good effect. I've replicated the process but had no luck. I've inspected these weak heads and cannot see any contamination, so that leads me to believe that the heads aren't contaminated, just 'weak'.

Heads in this state on these models don't come right when I clean them, so swapping in new heads is still the procedure for me. Does anyone have a different approach? More than anything I'm interested in the science behind how they become weak instead of failing altogether, and I guess I've answered my own question of why they read the outer tracks OK, due to the angle being beneficial?

Input would be interesting, thanks.

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Data Recovery Cape Town

Heads can get weak by brief surface contact like touching down during shock or hitting a bump caused by a previous contact. The reading element can heat up very fast to undesirable temperatures that change their crystal structure or demagnetizing the pinned layer. These can lead to weak signal production.
But i also think you are right about the point that the bandwidth is lower towards the ID, so it would be reasonable for them to read better there. I'm not sure why you experienced this the other way. Maybe the spring suspension gets weaker and the air makes it vibrate more as the angle gets higher. I think it would be useful to check the signal with a scope.

pepe

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Adatmentés - Data recovery

The following tutorial suggests that the angle is 0 somewhere in the middle of the disc rather than the OD or ID.

HDD inside: Tracks and Zones:
https://hddscan.com/doc/HDD_Tracks_and_Zones.html

ISTM that this would make more sense since the range would be 0 +/- x rather than 0 + 2x.

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A backup a day keeps DR away.

Mayby heat might be a factor. These drives get extreamly hot, and the heat could cause some problems. Try and see if some method of cooling them down might work.

@Fzabkar: yes, they usually put SA near the 0 angle, at least in F3 seagates, and all Hitachi-IBM, Hitachi-ARM drives.

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Adatmentés - Data recovery

@pepe - what do you have against Bitcoin donations?

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Death is nothing, but to live defeated and inglorious is to die daily.
Data Recovery Cape Town

it reaches back to a time when Spildit tended to share info stolen from paid tools and he had a wallet ID in his sig. I had a strong discomfort with the way he did it, sharing info what he extracted from pc3k and calling it research and accepting donations for such things, while he did not do any real research on his own other than gathering info from everywhere.
So on my side it was more like a protest against such behaviour. I help for free when i do, or i say a number if the issue is beyond the limits of free help (like when a solution took me a few weeks to figure out and implement).

pepe

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Adatmentés - Data recovery

I see, OK - and agree with your feelings. I was hoping it wasn't anything against my favourite currency, which it doesn't seem to be

_________________
Death is nothing, but to live defeated and inglorious is to die daily.
Data Recovery Cape Town

Spildit does not have PC3K, so he extracted nothing. He shared the information that he retrieved from public sources, primarily from Russian forums, so nothing wrong with that. But more than that, he and I did a lot of research and analysis from first principles, so he is entitled to accept donations for that, and for the maintenance of his forum.

AISI, the real reason for your animosity is that he was responsible in part for disrupting your secret society and making data recovery accessible to the wider community. Ironically, Spildit's efforts have no doubt substantially increased the revenue of Ace Laboratory, so they would not share your sentiments.

_________________
A backup a day keeps DR away.

Once upon a time I PM-ed a person(on this forum) who's the active member of the HDD Oracle some information about new Hitachi drives (just because I wanted to help, I've got nothing from it) and the very same day he shared it on the HDD Oracle without even asking me.
So I would say phishing for information is one of the ways of obtaining data that ends up on the HDD Oracle. I personally just don't want to have any relations with unscrupulous people, that's it.


That's your belief and you made it clear from the very first day you joined this forum.
And it looks like your desire to make harm (ie "disrupting your secret society") is overshadowing your desire to help people.
Some people just don't like you because of that. Not because you "disrupting your secret society" but because you are simply bad, unpleasant, and egocentric person.

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SAN, NAS, RAID, Server, and HDD Data Recovery.

I share freely and without reward. That's why I'm hated and targeted. I have confessed my ignorance on numerous occasions, but I do have knowledge and experience that others will never have. That makes people jealous. As for being bad, unpleasant, and egocentric, take a look in the mirror sometime.

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A backup a day keeps DR away.

Do you mean the ROM image that you passed to me on July 2018? I didn't know then (and you didn't tell me) that it is a secret. Everyone could read it by a programmer...Indeed I shared the image with Spildit and he posted it on his site. I do appologize.

That's the secret? :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:

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A backup a day keeps DR away.

I didn't say that it's a secret, I simply said that I shared info through PM. If I wanted to share it publicly I would, but I didn't. For me PM would be reason enough to ask permission to share it publicly, for you it would be ":lol: ". I guess that's the difference between me and you, since we are both bad, unpleasant, and egocentric.

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SAN, NAS, RAID, Server, and HDD Data Recovery.

That's why I dislike this business and many of the people involved in it. Fortunately, one of your peers shared his considerable ROM resources with me, so I was able to do my analyses without your secret ROM dump. BTW, do you know who "magic.mike" is? He seems to have access to some stolen HGST information. Is that how the data recovery tool developers do their "research"?

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A backup a day keeps DR away.

Because they always remind you that you need to be respectful?

This guy?

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SAN, NAS, RAID, Server, and HDD Data Recovery.

@Doomer
Some history
A Russian from Vladivostok shared with me VSC's that read the ROM of all HGST ARM drives. A few weeks later a Russian from Chicago shared with me a ROM image of a drive that I don't have available. At that time I thought that my VSC's would work with this model. So what's the big fuss? Where is the Russian generosity?

I'm not sure why you keep bugging me.
You asked for ROM - I gave it to you, privately.
You shared it publicly - that's your decision.
I didn't like the fact that you didn't ask me before sharing that's it.
You can't change what I like or don't like, you shouldn't care either(you didn't before).

I'm not on HDD Oracle and never will be I found out that the ROM was shared after some time, accidentally.
I don't like how HDD Oracle operates.
For the same reason I'm rarely on the ru-board site. Both HDD Oracle and ru-board are full of stolen info and data recovery wannabes, majority of whom is not very smart and such crowd is not to my liking.
I'm on this site since the beginning, and I changed several forums before, that opened and died before my eyes.
I like this site and I like the people here (except for some individuals) and I like the fact that this place does not share stolen info and does not have the crowd of HDD Oracle.

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SAN, NAS, RAID, Server, and HDD Data Recovery.

Franc, if you really would like to help people, you would have told that guy at TomsHardware forum where to look for F3 rom recovery. Simply because you like helping. Since this is out of sight for you i do think your motivation comes from somewhere else and it is close to promoting your ideas and ways and pouring shit on others'. In such situation the helpful attitude is to tell the poor chap where to look, not just hooking him with BS.

the post i was refering to was in the 'research and development' section of the forum. No matter how he acquired the before and after mod02 images, a simple hex compare to reveal something is not research, it is simply stealing the info from that tool's authors and publishing it.
I also wrote there that it is the most trivial thing i also did out of curiosity back then. For myself but not published it coz i did not think it's a right move. And it is definitely not research.
Anyway, it is past, i didn't really want to bring this topic up again. I hope he's OK.
pepe

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Adatmentés - Data recovery

This is not true. My post was:
"@Doomer
Coold you upload the ROM image of such a drive?"

What makes you to think that I'm asking for something ?