Here is the second conflict I run accross and it concerns the storage of the SA A and SA B firmware. Just curious which is the correct statement and storage positioning for the firmware of these drives. Maybe it is not important just curious to find out which one is correct that is all.

Statement 1

A hard drive consists of two or more copies of the service area information which are stored on different platters of the drive

Statement 2:

The Service area information often lives in two places on the platters of the drive. The area outside of the platter 01 which is accessed by the 01 head, and the second area is near the parking zone which is accessed by 02 head.

Thanks

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Iorana Haraharaini

And on N40p mono head and single surface? THINK!

Exactally my point. These statements were takes using examples of N40P series Maxtor drives. It is competely incorrect stating that the SA B is read by head 02 when there is only one head on the drive. It is possible to store the copies in two different locations on the drive but not possible to read with two different heads on the drive. Plus SA information is stored on the negative sectors of the drive either near the outer most edge of the drive or the inner most area of the drive near the parking zone. These two statements were found on different data recovery companies web sites and were pubished there explaining SA problems inside the maxtor drive and how their companies have descovered these features of the N40P hard drive firmware problem and can resolve these problems by understanding the location on the drive SA to repair corrupted firmware modules.

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Iorana Haraharaini

Negative sector on N40p and friends = bullshit - in italian: cazzate. Maxtor pre-seagate use UBA notation for SA, and you can always convert Uba to Pchs and the result is not negative... IT'S A MATTER OF CONVENTIONS.

Each manual has a different explaination on this mater. It seems that everyone has their own ideas of how this works all together. I have not found any two explainatons on this statement the same anywhere. I have seen variations of this statement with slight ideas changed to suite the purpose of posting on the recovery web sites. I checked in the manual with ACE and found this in there manual.

In Maxtor drives the service area is accessible through logical sectors specifically assigned for that purpose and called UBA (Unit Block Addressing, somewhat similar to LBA) automatically converted by the microcode into respective physical location on disk surface taking into account the defects in the service area. The service area occupies the outer cylinder (disk edge) in half sized HDD and internal cylinder (closest to the parking zone) in full sized HDD.

Other manuals explain that SA is stored on negative sectors on disk, other indicate they are stored in two different disks, other say in separate locations. I guess the only way to find out is excatally where they are stored is either by finding the manufactures construction manual or by using a hex editor to look at all sectors on the disk to determine the locattion.

If you take into account the statemetn in the manual the UBA is automatically converted by the microcode into respective physical locaton on disk surface. 2.5 stores on outer edge of disk surfae and 3.5 stores on inner edge of disk surface. Maybe that is the confussion behind this statement and people have modified it greatly to suit their own needs. How else could they arrive at the conclusion it is stored in two different locations on the disk surface. They are confused by the 2.5 and 3.5 drives and have combined them together and come to their won conclusion it is stored in two different location on the disk surface. Maybe I am very wrong in this conclusion but you can never find any two statements alike or any two explainaton the same in this area of these disks.

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Iorana Haraharaini

What can I say ? 99 % of websites are cut / copy / paste from other, so manuals may be. One thing is sure : on Maxtor pre seagate there is UBA notation for service area and ABA for user area. No "negative tracks" as the conversion from UBA to PCHS gives a FINITE value. PERIOD.

P.S. it was really important for drives without ALT-SA (prior to 2004) when you had some bad blocks in the SA ... what to do ?

P.P.S. what about the drives that have SA in the middle or "scattered" (yes, there are) and what about the SA relocation mechanism ? That's why is nonsense the concept of negative tracks....

P.P.P.S. (edited again...) ... negative tracks "can be" IF the drive interpretates a negative track value in special notation AND internally addresses the right block... but it's another story.

As a side note I think this is referring to half-height 3.5" vs. full-height 3.5", not 2.5" and 3.5" (at least I've never seen a 2.5" Maxtor).

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

Thanks that clears up a lot of grey areas that are in manuals and posted on the Internet. I understand clearly what you are saying and thank you for clearning up this mater. You have been very helpful. Just curious when I run accross things like this and there is such a conflict of answers out there just wondering what is the true answer behind all of this.

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Iorana Haraharaini

On Western Digital HDD's SA is located on "negative" cylinders, not Maxtor.

If it's negative, it is in the spindle or outside the platter

Cylinders are always numbered from 0 to n, the "negative track" is a definition for some brand, but there is ALWAYS a FINITE POSITIVE NUMBER for physical C/H/S, i.e. the modules are stored on "positive" blocks... re-read what I said.