How to test if write works on drive with data?

[jasonarthurtaylor]

I am confused about something. Perhaps it is a bug. There seems to be only one test that checks write capability of a drive that has important data. It is "read+WRITE+read". Is that correct?

With this option, does the software read a sector, then write it? If so, why is there a different tab in which you can fill disk with zero or other pattern?

Also, I want to scan write capability of a whole drive as fast as possible. I don't want to take it offline. Really I want to check if there are any errors, since I know that unless drive is writing it is not really checking all aspects of drive. Should I selected 1 pass on the other tab? What settings do a quick refresh and check for errors?

[hdsentinel]

Excuse me for the confusion.

I can confirm that there are no bugs - can you please let me know why you think about it?

> There seems to be only one test that checks write capability of a drive that has important data. It is "read+WRITE+read". Is that correct?

Yes, this is absolutely correct.
Generally, the "safe" tests - which are safe for the stored data do not perform "write", just read the disk surface.
These are Disk menu -> Short self test, Disk menu -> Extended self test, Disk menu -> Surface test -> Read test.
These can be started, cancelled any time and even worst case scenarios (for example power loss, sudden reset or removal) has no harmful effect as the complete surface area is used for reading.

If you prefer to verify the write capabilities then you need to use any of the other tests, as they perform write to the disk surface.
However, the Disk menu -> Surface test -> Write test, Disk menu -> Surface test -> Write+read test, Disk menu -> Surface test -> Reinitilise disk surface tests are both destructive, which means that the hard disk surface is overwritten with zeroes, random data, sector numbers (according the write pattern option specified when you select Disk menu -> Surface test and in the new window, select the Configuration page to modify the test options).

If you prefer to verify the write capabilities but on a hard disk which contains data, then yes, the Disk menu -> Surface test -> read+WRITE+read test is usable, which is designed exactly for this purpose. It reads the sector contents, write back the data and verify if it's written back and compare with the original data.
This is the best way to perform on a hard disk drive / SSD / flash device (memory card or pendrive) which contains data.
This test is even designed to "refresh" stored information especially for such flash devices (memory card or pendrive) to improve performance and data availability (as such flash based devices may not able to hold data for longer time - or just their performance may decrease with time).

> With this option, does the software read a sector, then write it?

Yes, exactly as you wrote - and as described in the test description when you select the test in Disk menu -> Surface test.
During this test, Hard Disk Sentinel
1) reads a sector
2) writes a special pattern to the sector (which can be zero, random data or sector number - according the configured pattern on the Configuration page in the disk test window). This step can be disabled if you un-select "Extensive read-write-read test with additional write operation" option on the Configuration page in the disk test window, just before starting the test
3) writes the original sector contents back
4) reads again and compare with the original sector contents.

> If so, why is there a different tab in which you can fill disk with zero or other pattern?

Because when you select the other tests (Disk menu -> Write test, Write+read test) where you can also specify the patterns, then the sector is overwritten with the selected pattern, permanently clearing the previously stored data. This is why those are destructive tests.

If you use Disk menu -> Surface area -> read+Write+read test, then this option can be used to specify the special overwrite pattern (mentioned in step 2) exactly to "refresh" the sector state: to force the hard disk / SSD to write back different data (not only what was written previously there).
This forces the hard disk drive / SSD to actually change the sector contents and then write back the original contents - plus verify if the contents are really same as what originally stored there.
This is the best way to verify if the device can really hold data and verify both reading, writing and data communication (between the hard disk/SSD and the computer) capabilities in general.

Notice that if you uncheck the "Extensive read-write-read test with additional write operation" option, then the option to select the pattens turn disabled, indicating that there is no such extra write operation will happen (so it is not possible to select pattern, as only the original data will be written back).

> Also, I want to scan write capability of a whole drive as fast as possible.

Then I'd suggest to disable the "Extensive read-write-read test with additional write operation" option.
Then Hard Disk Sentinel will read the sector and write it back immediately, plus reads and compares the written data with the original sector contents, just to make sure that after the test, the data is present as should.


> I don't want to take it offline.

For write type of testing, the hard disk / SSD need to be locked (unmounted) for exclusive access to prevent other software and Windows from accessing the hard disk during test. Otherwise it is possible that something will modify the contents of the sector before the test would write it back (so the test would write back the "old" data), resulting an inconsistent state.
Generally, this is why chkdsk /f also needs that the partition should be also unmounted (unavailable for the system and other programs) to perform fixes/writes.
(usually I do not like mention chkdsk - as chkdsk does not care about hard disk status, just checks/fixes the logical volume/partition, but shows how things work when something need to write to the hard disk).

> Really I want to check if there are any errors, since I know that unless drive is writing it is not really checking all aspects of drive.

I completely agree.
Generally, this is why I always recommend to perform the BEST way to verify write capabilities by using the Disk menu -> Surface test -> Reinitialise disk surface test, even on a new hard disk before filling with important data.
This is the best way as it uses several special overwrite (initialization) patterns and then clearing the stored data and then verify the actual contents.
But this is a destructive type test and needs longer time - but it surely detects and reports problems and fixes any kind of sector problems.

See: http://www.hdsentinel.com/faq.php#tests ( Hard disk health is low or recently changed or I just installed a new (used) hard disk. How can I perform a deep analysis? )
The first steps are the non-destructive tests which can be performed any time - but I also recommend to verify write capabilities by the Disk menu -> Surface test -> Reinitialise disk surface test also.


> Should I selected 1 pass on the other tab? What settings do a quick refresh and check for errors?

Just disable the "Extensive read-write-read test with additional write operation" option.
This immediately eliminates the additional write step, resulting in faster read+Write+read test, which also checks and reports all kind of errors happened during
- the initial read procedure
- the write procedure (when the sector contents written back)
- the 2nd read procedure
- or when the data read procedures result in different data, confirming that the data somehow corrupted (for example during data transfer).

[jasonarthurtaylor]

Thank you for a great answer.

I now change my mind about a bug.

The only possible improvement is to change the color from blue to greenish-orange. If you mix blue and red paint equally you get brown, however, with light mixing you get orange. Since it is 99% green it should be slightly orange and mostly green in color. I think Jade may be the best color. Blue? That is the wrong color to use IMO.

Also, I think there should be a feature to write to a partition that is open on a drive. This would allow a write test on a drive in use, since one can always make a fresh partition. I have tested drives in read only and only later found out that the drive's issues only showed up with writing tests.

[hdsentinel]

Thanks for your message and the suggestions!
To be honest, yes, originally orange color was planned - but worried that it can cause confusion as it can be seen as yellow (or even worse) red and this may cause troubles. Not sure about the actual "jade" color, but if you can send RGB color codes, I'll check

I can confirm that different test functions/options are planned, mostly to make things (error detection and repair) even easier.
The main focus is the diagnostics of the hard disk devices on the "lowest" level which is independent from partitions (as this way it is possible to test hard disk drives / SSDs even with no partition at all or partition(s) unreadable for Windows) but yes, it may be a good idea to add partition-level testing as well, so it may be available in a future version.

[jasonarthurtaylor]

This is a good color.