greetings everyone,

my hdd is not recognized by BIOS , a "pro" examined it and figured that its the NVRAM

the hard spins so whats the solution ? replace the NVRAM from identical PCB ?

thanks

No, NVRAM is specific to the drive

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You don't have to backup all of your files, just the ones you want to keep.

yes , but wouldn't another NVRAM from the same model with the same MLC and PCB number work ?

1% maybe
99% no

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You don't have to backup all of your files, just the ones you want to keep.

So, in this case if you don't have the experience for such cases, you should go to a DR company to do it.

I'm not a data recovery guy, but ISTM that if the hard drive spins, then the MCU must have verified the NVRAM's checksum, in which case the NVRAM's contents must be intact. This assumes that the NVRAM is original, and that it has not been reprogrammed.

Does the HD still have its original PCB?

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A backup a day keeps DR away.

I guess if you were a DR guy we would all be in trouble. First thing for you to understand is how the hard drive spins up. Just becase you feel that the MCU has read the NVRAM chip does not mean it will spin up. You have to realize it is not a one step process. So the frist stage worked great the MCU read the NVRAM and spun up the drive but after this it can not proceed on to do anything else. That means you can have corruption in the NVRAM as the repair shop thinks it is or you can have problems in the SA or other reason behind this one. You are so good on search functions and copy and paste techniques maybe you can try doing so search on NVRAM and drive boot processs. I sure we would all be delighted for you to do this one. If you are as talented as you think I am sure you can find what I am talking about. Read up on it and you will see that the boot process is not one step. There is a lot of factors that come into play when a HDD boots up and becomes ready so you can use it. Guess what not all are related to your TVS either on this one.

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Iorana Haraharaini

Ann, I know very well how a hard drive bootstraps itself. I have explained the process several times in other forums, and perhaps this one as well. The fact is that a uP needs to verify the integrity of any ROM code before it executes it. AIUI, after the MCU's masked bootstrap code loads the contents of NVRAM into SDRAM, it first verifies its checksum before transferring control to it, or at least that's the way it should be done. It would be extremely unlikely for the original NVRAM to be corrupted without its checksum also being invalidated.


Ann, how many more times must I publicly confess, in this forum and others, that I know very little about modern hard drive technology? The above statement is your opinion, not mine.

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A backup a day keeps DR away.

Ummmm Franc: looks like he had this examped by a "pro" what is "pro" to me "pro" means he took it to a DR company and had it examined. BTW if NVRAM is bad yes the HDD can spin up but that is about all it can do.

But considering you love to post replay I leave it at this. There is absolutely nothing anyone can say that you do not have some answer back to them on it. Guess this is your character and the way you are. You hate to have anyone dispute with you. Well Franc I don't GAS on this one. Me personally I could care less about your answers back to me. If you wish to dispute all everyone says have a go at it. Like You are the man on TVS and each Pro knows nothing in your mind about Electronics or how this works. But be careful when you claim this one becasue we know a lot on electronics and how the drive works and operates otherwise we could not do our job like we do. We do know electronics even if you think we don't ......

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Iorana Haraharaini

Ann, there are many "pros" who claim to be pros. That doesn't make them so. In fact, aaly's use of quotation marks suggests that aaly isn't convinced, either.

As for the remainder of your rant, you are just putting your words in my mouth. In fact I sincerely wish that you or your colleagues would correct all my errors, as I do theirs. Merely saying that I'm wrong, or that you're right, doesn't suffice. After all, this is the Internet where anybody who thinks they are somebody can say anything.

That said, I'd like to see confirmation from your colleagues that a drive can spin up with a faulty, or missing NVRAM.

FWIW, here is a description of the "Seagate hard drive boot process":
http://www.datarecoverytools.co.uk/2010 ... t-process/

step 1: Power up the drive

step 2: Wait until the voltage is stable

step 3: R/W test and peripheral equipment test to MCU, register and SDRAM, if returning with errors, it enters infinite loop

step 4: Test if there’s external flash - load flash and verify - load inner flash - hard drive motor start up

ISTM that NVRAM is tested and verified before the motor starts. I can't imagine why Hitachi would do it any differently.

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A backup a day keeps DR away.

Now is expected someone will correct this bullshit so someone will know a little bit more. Isn't it?
Tell lies to get truth / social engineering.

You know the truth , but you are not willing to say it (for free). Correct?

"Who" knows ?

According to the following document, the OP's drive supports Power-Up In Standby (PUIS).

Hard Disk Drive Specification Hitachi Travelstar 5K320:
http://www.hitachigst.com/tech/techlib. ... ec_r14.pdf

The enabled/disabled status of PUIS must be stored in NVRAM, not on the platters. Therefore, it stands to reason that the MCU must retrieve the PUIS status from NVRAM before deciding whether to spin up the drive. Furthermore, it also stands to reason that the MCU would verify the checksum of the NVRAM before trusting its contents.

If the OP has not touched the drive, then I can't understand how the NVRAM could be corrupted in such a way as to maintain a valid checksum.

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A backup a day keeps DR away.

The PUIS flag is within the NVR on HGST. Maybe it's worth trying Hitachi's Feature Tool to modify the PUIS setting. (If the SW supports PUIS)

http://www.hitachigst.com/support/downl ... eatureTool

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All went well until I plugged the drive in.

Shouldn't the drive still be recognised by BIOS, albeit with a cut down version of the full Identify Device info?

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A backup a day keeps DR away.

yes correct it should still partly ID. Ahhh after reading the whole thread his drive does spin but with no ID.

:O) Note to oneself Always read the whole thread!

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All went well until I plugged the drive in.

I've seen bad heads give the same symptom in this series.

In our experience with Hitachi 2.5" drive failures, heads failure is most common (other than bad sectors).

The drive will spin up fine with non-native NVRAM. We've yet to see one with a checksum error, but it would be easy to test if this would prohibit the drive from starting the motor.

Franc, why don't you corrupt an EEPROM and let everyone know what you find out?

Jono

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http://www.datasaversllc.com

Jono, you are asking too much...

I don't think so. Nothing is to difficult for our friend fzabkar.

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http://www.datasaversllc.com