I have a 600 GB HDD by WDC, model WD6401AALS-00L3B2
Via 64 bit Windows 7 Ultimate Disk Management I have changed its status from Online to Offline,
and I now have Read Access for data recovery purposes,
and believe it is write protected against normal Windows capabilities until I change status from Offline back to Online.
Is the HDD now Offline because this installed Windows 7 has set a private flag in its registry etc.,
Or has a special flag been set in its first few sectors that stipulates to all forms of operating system that this HDD must not be written to,
Or has it issued a special ATA Protect command sequence that told the HDD controller to ignore all writes until it receives a special ATA UnProtect command ?
Upon starting up, as Hardware initializes,
there is chaos as Boot Up progresses though the BIOS and into a Boot Device to launch an Operating system,
Would this HDD remain protected against writes throughout that progress into the Operating System of the Windows 7 installation which set "Offline"
Would this HDD remain protected against writes throughout that progress into other Operating Systems (WinPE, Linux, etc) which did NOT set "Offline"
Will an alternative Operating system such as DOS or Vista or Linux etc. still write to the HDD
Would the drive be safer against writes if I electrically disconnect (with power removed).
and if so should I locate and disconnect both SATA and Power leads to the HDD ?
BACKGROUND (No further questions - just explanations. observations, assumptions - sorry it is so long).
This HDD was GPT style.
It is now confused by Windows as MBR,
a 25 GB partition was NTFS and is now RAW,
and a 500 GB partition has become unallocated space.
I have two different Data Recovery tools that both see the same thing and each are able to recover 418 GB of files.
Each tool has a limitation so I have only saved to my main HDD a 615 MB toolset.
I am waiting for an imminent enhancement to the recovery tools before I recover and save the other 99% of the 418 GB of "lost files".
So while life goes on I wish to preserve the "integrity" of the lost files.
When I switch on the computer in the morning Windows detects and reports the Disks as :-
0: WDC HDD
1: Samsung HDD
2: OCZ SSD
When I "RESET" the computer (e.g. because a software update requires it),
then the SamSung HDD is always Disk no. 2,
and the OCZ SSD is mostly no. 1 but sometimes no. 0 (pushing the WDC HDD down to no. 1)
The Power Up / Restart difference between Disk Numbers suggests that the HDDs respond to the BIOS before they have run up to speed,
and the OCZ SSD takes a lot longer to wake up from a shut down,
but a brief blip of a Reset causes the Samsung HDD to lose out to the OCZ SSD, and sometimes also causes the WDC to lose out.
On the day of chaos I used a new Linux Boot Flash Drive for the first time,
and within less than 5 seconds Linux crashed and the BIOS restarted and I allowed a normal progress into Windows.
Windows Promptly put the SAMSUNG HDD OFFLINE because the WDC HDD already had the same Disk ID (000FA830) as the Samsung
(and Windows cannot tolerate two Disks with the same Identity).
DiskPart is able to change the WDC Disk ID to a different MBR style number, but refuses to allocate a GPT style GUID to what Windows sees as a MBR disk
I deduce that a cold start power-up start-up results in a race sequence of WDC, Samsung, OCZ
and a simple Windows Reset give OCZ an advantage over Samsung and possibly WDC
but an aborted Linux Collapse and Windows Launch has caused either the BIOS and or Windows to observe and remember the Samsung Disk ID,
and perhaps due to SATA channel / Disk number chaos either BIOS or Windows has thought the WDC had forgotten its Disk Identity and written the Samsung identity in place of the original WDC GUID style identity.
I have used the same Linux code with other Flash Drives so I know that Linux did no harm.
I suspect the economy brand Flash Drive simply dropped some bits from its NAND cells,
and all the rest of my problems are due to the inability of Windows to allocate Disk numbers according to SATA Port/Channel numbers.