Hard Disk Monitoring

I have learned a great deal about drives reading these posts and in using HD Sentinal.

With a couple of dozen drives used (hard) for video editing and many are for simple storage (to preserve the data for several years), I am interested in using HD Sentinal to refresh or restore drives, at least to the extent possible.

I especially keep in mind that the disk bit magnetic fields, as I understand it, fade over time even if the disk sits on a shelf. That is my reason to try to re-initialize them, hopefully to re-record the data with restored magnetic levels (and deal with any sector reallocation that needs to happen).

Does this logic hold water?

Furthermore, I see the HD Sentinal re-initialize function and it, of course, requires one first to clear the drive of data. But with large drives-- that is, 2-3-4 terabyte size-- this off-load and re-load can take significant time and of course requires an other large drive.

Would it be faster to have an HD Sentinal function that would re-initialize an unused portion of the target disk, then move drive data onto that newly initialized portion? By repeating this process with the newly cleared space, the entire disk could be re-initialized (and without the need for a separate drive), right?

In the end, though, there might be no time advantage, only that no second drive is required for backup.

Thanks again for a great program.
Mike

Thanks for your message and the information !

> I especially keep in mind that the disk bit magnetic fields, as I understand it, fade over time even if the disk sits on a shelf.

Excuse me, but this is not true - except if your shelf would have strong magnetic field
(which may re-program the magnetic media).

Unlike from the memory cells of SSDs (where the data can *really* fade over time if the device is not used) the magnetic fields do not fade away stored information. The magnetic field can hold the stored information without this "forget" effect and can be re-programmed unlimited times.
These are major differences between the hard disks and the flash-based memory cells in the SSDs.

Anyway, I completely agree that the drives could be periodically tested and even re-freshed, if you prefer that.

However, exactly for this purpose, Hard Disk Sentinel has a special test, called "Read + Write + Read test (Refresh Data Area)" available at Disk -> Surface test.
This reads all blocks of the drive, writes special initialisation pattern ("extensive test"), then writes back the stored information and compare with the original data (please check the Help and description of this test before started). This ensures that the device would keep the stored data safely.
Originally this feature developed for USB drives / memory cards to "refresh" not only the stored information but the state of the drive (as these devices may not have wear leveling compared to SSDs). But it can be used for hard disks as well of course.
This way there is no need to move data to an other drive for the duration of the Reinitialise Disk Surface test and then move data back - so it makes things faster.

Thank you for your complete and speedy reply to my questions regarding disk bit magnetism "fading" over time and also my question about a way to re-initialize a disk without having to off-load all the data first.

You said that disk bit magnetism does not fade over time and I also understand from your reply that no "refresh" or re-initialization is helpful in that regard.

I also understand that the "Read-Write-Read" test accomplishes the same re-initialization of the disk surface as the surface "Re-initialization" test; both are in the Disk>Surface Test menu options.

Thank you. That clarifies things. In fact, the "Read-Write-Read" test is the one I have been using. But I did not realize it accomplished the same Re-initialization as the dedicated "Re-initialization" function.

I appreciate your help with this.

Yours,
Mike

Can you elaborate more about re-initialize functions? I am still in a fix for proper functions and features too..Is it resemble with two factor authentication in Google apps ? Find http://www.googleappsecurity.com/google ... y-features

Hard Disk Sentinel Professional has a function in Disk menu -> Surface test called "Reinitialise disk surface".

This is designed to completely erase all user-accessible areas of the hard disk / SSD / memory card / pendrive / internal memory of a device by multiple-pass overwriting with special patterns and then clearing the sectors and reading back the contents to verify that the data can be read back and completely erased.
This is called DoD or NavSo data drestruction.

If you select the test, then (before starting it of course) Hard Disk Sentinel Professional displays the following description about the test:

Overwrites the disk surface with special initialization pattern to restore the sectors to default (empty) status and reads back sector contents, to verify if they are accessible and consistent. Forces the analysis of any weak sectors and verifies any hidden problems and fixes them by reallocation of bad sectors (this is drive regeneration).

Enables better use of the disk as after the test the spare area will be used instead of any problematic sectors.
Very intensive and time-consuming test, especially if the level (the number of overwrite cycles) is set to higher value.

The simple version of this test is usually (incorrectly) called as low level format by other tools.

For more information, I'd suggest to check Help -> Hard disk tests section from the software or in the online help available at: http://www.hdsentinel.com/help/en/index.html

The simple version of this test is usually (incorrectly) called as low level format by other tools.

Is windows "full format" also a simple version of "Reinitialize disk surface"? Full format seems to take less time.

Like chkdsk, windows full format probably works at partition/volume level, and never fixes bad sectors. Re-initializing a 4TB drive seems to take about 391 hours. I wish windows full format could be a simple version of re-initialize.

Windows full format performs a read only on the sectors.
It never fixes the bad sectors or weak sectors, but (like chkdsk) only marks them as "bad" at the file system level.
The result is that the problematic sectors are still used (not replaced from spare area) and upon complete repartition / reformat, they'll be used again.

If you prefer a faster solution, please try Disk menu -> Surface test -> Write test. This is much faster than the Re-initialise disk surface test and if the amount of problems are relatively low (for example only some weak sectors reported previously) it may help and repair the hard disk completely.
Then (after creating partition(s) on the hard disk) even a quick format is perfect in Windows - so this saves time.

jack150731 wrote:Is windows "full format" also a simple version of "Reinitialize disk surface"? Full format seems to take less time.

Absolutely NOT.

Windows full format only performs a read scan of the data sectors. It does not clear data except the MFT / directory areas.
Also does not really care self-monitoring parameters, temperature, performance / slower accessible areas, possible retries, etc..

If you use Hard Disk Sentinel -> Disk menu -> Surface test -> View and click on the surface map to check the raw contents of the data sectors, you may notice that most sectors are not empty after a full Windows format (if the hard disk was originally full).
This is why it is relatively easy to recover data from a cleared, formatted partition.

In contrast, if you use Disk menu -> Surface test -> Reinitialise disk surface (or just the write test) and during the test click on the surface map to inspect the sector contents before and after the overwrite, you may notice that all data really cleared, the data sectors contain only zero (00) bytes.

Personally I never recommend a Windows full format.

I'd more recommend the above mentioned write type tests to repair problems - and if we have "time", then a Disk menu -> Surface test -> Read test
before creating partition(s) and use Windows QUICK format for them.
This is better option as the Windows full format would not care about parameters (but the Hard Disk Sentinel read test does), so then a quick format is enough just to create the new MFT and make the partition usable.

hdsentinel wrote:Windows full format performs a read only on the sectors.
It never fixes the bad sectors or weak sectors, but (like chkdsk) only marks them as "bad" at the file system level.
The result is that the problematic sectors are still used (not replaced from spare area) and upon complete repartition / reformat, they'll be used again.

hdsentinel wrote:

jack150731 wrote:Is windows "full format" also a simple version of "Reinitialize disk surface"? Full format seems to take less time.

Absolutely NOT.

Windows full format only performs a read scan of the data sectors. It does not clear data except the MFT / directory areas.

No, that is not true. The Windows full format overwrites since Vista all sectors within the partition with zeros.

Microsoft wrote:The behavior of the format command changed in Windows Vista and later Windows versions. By default in Windows Vista and later versions, the format command writes zeros to the whole disk when a full format is performed. In Windows XP and earlier versions of Windows, the format command does not write zeros to the whole disk when a full format is performed.

https://support.microsoft.com/en-us/kb/941961

Thanks for the clarification. Yes, since Vista, the full format writes zeroes to the disk surface - but under older OSes like XP, 2000, 2003, NT4 the format command only performed a read.

So performing a complete format under Vista or newer Windows is almost similar to the Disk menu -> Surface test -> Write test in Hard Disk Sentinel, except that
- the write test in Hard Disk Sentinel performs overwrite of unpartitioned space (may be important when required to clean such information, for example some data saved by RAID controllers, partition managers, boot managers, other OSes)
- the write test in Hard Disk Sentinel verifies and reports unaccessible blocks, damaged blocks (where retries required), verifies disk performance and report slower performing blocks
- Hard Disk Sentinel has options to perform overwrite with different patterns

in addition to simply overwrite with zeroes.