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 Post subject: About S.A : where is it located ? it's essential ?
PostPosted: February 1st, 2019, 13:40 
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I know that for many it will be a stupid question, but on hard drives with multiple platters :

1- Is the SA located in several platters or in only one?

2- Is it essential to read it in order to boot a hard drive?


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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 1st, 2019, 13:53 
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usually one platter but both sides
it is essential for a drive to read SA in order to boot

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 1st, 2019, 14:34 
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And you can not crack the firmware so that it does not go to look for the SA?


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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 1st, 2019, 15:15 
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fender wrote:
And you can not crack the firmware so that it does not go to look for the SA?


The firmware IS on the SA (Service Area), well the vast majority of it is. Specifically the useful stuff like defect tables, translator, head tuning adaptives etc....

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 1st, 2019, 15:17 
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fender wrote:
And you can not crack the firmware so that it does not go to look for the SA?

Hmmm. Sounds anti-data recovery.....

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 1st, 2019, 15:24 
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ddrecovery wrote:
Hmmm. Sounds anti-data recovery.....


jajaj no no, I'm just learning about hard drives, and I wanted to know how indispensable it really is the SA that is on the hard disk platters for a recovery.

Imagine that just the SA has a scratch, Game over?

You can´t avoid it ?


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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 1st, 2019, 15:28 
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The SA is stored in at least two places (sometimes 4) on modern drives. Some of the FW is unique to the drives such as the translator and if those unique parts are lost then the drive is toast, but some FW is interchangeable. All depends on what area is corrupt.

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 3rd, 2019, 10:29 
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Just read here : - http://www.hddoracle.com/viewtopic.php?f=56&t=176

READ ALL LINKS.

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 3rd, 2019, 14:19 
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Thanks very much for the info. I will read it.


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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 3rd, 2019, 17:17 
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newbie info, from and for newbies :) About firmware, SA, etc:
https://forum.hddguru.com/viewtopic.php?f=16&t=6562

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 6:56 
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After reading all the links I still have the doubt of whether reading the information contained in the SA (on the platters) is absolutely essential to read and interpret the data on a hard disk or on the contrary it can be "bypassed" by modifying the firmware of the PCB.

That is, if the sectors of the platter( or platters ) where the S.A is is completely destroyed (headcrash for example) make it necessary to give up.

I also understand that certain brands, such as Toshiba, that have an exclusive firmware for each specific unit, will look for the password in or certain vital information to confirm that this platter belongs from that drive, therefore accessing the S.A would be something vital. But in other models I understand that no ..¿ im right ?


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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 7:43 
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For example SMART and G-list :

Are they completely indispensable and unique to each unit?


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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 10:05 
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fender wrote:
After reading all the links I still have the doubt of whether reading the information contained in the SA (on the platters) is absolutely essential to read and interpret the data on a hard disk

Better go back and read it all again, but this time slow down by a factor of 10 and try to actually understand what you're reading.
fender wrote:
That is, if the sectors of the platter( or platters ) where the S.A is is completely destroyed (headcrash for example) make it necessary to give up.

If the SA is completely destroyed, it's unrecoverable 100% of the time. There's nothing to even bother attempting.

fender wrote:
or on the contrary it can be "bypassed" by modifying the firmware of the PCB.

There's very little firmware on the PCB beyond what it needs to be able to read the SA, where the other 99% of the firmware code is stored. Including all the drive specific adaptives, translation, etc. etc. etc. Rebuilding all of this from scratch would be the equivalent of guessing a 1,000,000 digit long password. It's never going to happen.
fender wrote:
I also understand that certain brands, such as Toshiba, that have an exclusive firmware for each specific unit

No, all modern drives have parts of the firmware that are drive specific. In fact, most drives now have a whole lot of firmware data that is drive specific and most of it (sometimes all) is actually stored in the SA. Toshiba is actually different in the fact that a higher percentage of the drive specific adaptives are stored as configuration pages on the ROM of the PCB instead of the platter SA. So Toshibas are less susceptible to firmware corruption for this reason.

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 10:21 
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fender wrote:
For example SMART and G-list :

Are they completely indispensable and unique to each unit?


No. They're unique to each unit, but not indispensable. Those can both be cleared.

But the P-List, T-List, Translator, SED modules, head adaptives, service area adaptives, head adaptives, RAP, CAP, service area translator, and many many other modules are completely unique and are indispensable in many cases.

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Last edited by data-medics on February 4th, 2019, 10:33, edited 1 time in total.

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 10:29 
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I still think this post is about anti-data recovery.

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 10:35 
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ddrecovery wrote:
I still think this post is about anti-data recovery.


Perhaps. Clearly, it's by someone with a vastly over-simplified concept of how a HDD works.

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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 14:25 
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data-medics wrote:
ddrecovery wrote:
I still think this post is about anti-data recovery.


Perhaps. Clearly, it's by someone with a vastly over-simplified concept of how a HDD works.


I'm not a professional, but I like this topic as a hobby. That's why I do not understand many things and I ask.

Thanks a lot for the info data-medics :wink:


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 Post subject: Re: About S.A : where is it located ? it's essential ?
PostPosted: February 4th, 2019, 15:49 
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fender wrote:
data-medics wrote:
ddrecovery wrote:
I still think this post is about anti-data recovery.


Perhaps. Clearly, it's by someone with a vastly over-simplified concept of how a HDD works.


I'm not a professional, but I like this topic as a hobby. That's why I do not understand many things and I ask.

Thanks a lot for the info data-medics :wink:


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

http://www.hddoracle.com/viewtopic.php?f=46&t=1430

What do you think that will happen if you don't have P-List anymore ?

And what do you think that will happen if you loose "adaptives" for heads and media ?

You can live without S.M.A.R.T. and you can clear G-List loosing only data on sectors that were swapped by spares (if any) but as soon as you do add or delete a single entrie from P-List you are in for pain. Same as if you do loose data that tunes the heads to read the surface. Same as if you loose other unique to the drive firmware data ....

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