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Clarify the sentence "zero-fill your drive" please.

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When you Optimize a drive, like an SSD, the option to continue is given in a messagebox.

But the wording "zero-fill your drive" at first makes me think it is going to clear the entire drive, and not just the freespace.

Will you clarify this in an update?

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in relation to what?

if formatting, all the drive is over-written with 0's.
if wiping free space, all unused space is over-written with 0's.

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On 9/23/2018 at 07:44, isuma said:

Be a decent human being and do not defrag an SSD!

I think it just uses the Trim command - that is if it properly detects the drive as an SSD!

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I think that the OP is referring to the wording, not the actual operation. I agree, zero fill your drive does imply that the entire drive would be wiped. Just zero fill free space would be better,  but don't expect anything soon from Piriform.

Zero fill is confusing, as the zero-fill concept, much loved by the OCZ community about ten years ago. is pretty much obsolete now with the universal adoption of TRIM. Optimising with a global TRIM gives the impession of running a zero fill, but it ain't really.

 

 

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SSD's need to be '1' filled, four times too, not zero filled.

Default state for the chips is 1, and 4 levels deep.

Be aware that due to built in wear leveling, SSD's cannot be fully 'zeroed' so to speak. A portion of capacity is reserved by the manufacturer for wear leveling (promotes longer life) that the user cannot see or access.

Got something so sensitive you want NO evidence left then use a live version of Linux. Knoppix used to scramble/clear all ram on shutdown. Dunno if they still do or not.

Be aware that newer computers using DDR4 memory can keep data stored in their chips for a LONG time.

 

"Zero filling is a method of formatting a hard disk whereby the formatter wipes the disk contents by overwriting them with zeros. Each bit present in the disk is replaced by a zero value, hence the name zero filling. Once the data are overwritten with zeros, the process cannot be undone from the hard drive." - Bing definition

 

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what's the difference between zero filling, 1 filling or A filling for that matter?
I'm curious, surely the important fact is that it gets filled with something - anything - to overwrite whatever is already there.

I've also not heard before of any sort of memory that retains data after a power loss.
DDR4 had better bandwidth and lower power requirements, but my understanding was it still was fundamentally volatile memory like all it's predecessors.

maybe that's two new things learnt today? :)

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Mta, on a HDD you can use whatever character you wish, it will make no difference. As user data is scrambled and coded by the disk controller before being written to the disk there is no way to determine what sequence of ones and zeroes was used on writing nor what it will be on overwriting. So you can overwrite an unknown sequence with another unknown sequence, but you can never actually overwrite a one with a zero, or vice versa, as the scrambling removes the knowledge of whether a one or a zero has been, and is being, written. Overwriting a one with a zero is a logical construct far abstracted from the storage device.

On an SSD you can't overwrite anything, you can only write new pages, so the proposition that you can overwrite with zeroes or ones or whatever, no matter how many times, is merely fanciful.

To the SSD controller a page is either valid (i.e mapped to a lba and visible to the O/S) or invalid (i.e. not mapped to a lba and not visible to the O/S). This does not represent what the O/S considers to be live or deleted files. File life or death (and fragmentation as well, but that's another long bedtime story) to the O/S is specified in the MFT, or FAT tables. The SSD knows nothing of these.

Deleted (TRIMed) SSD pages will be inaccessible to any operating system. Garbage Collection will empty invalid pages by setting all cells to 'ones', and those pages will remain inaccessible until the SSD controller receives a write request and decides to use them.

DDR4 ram is volatile, but there are some hybrid cards with ram and non-volatile flash in the pipeline, perhaps this is what is meant. This is a long way from the O/P's suggestion.

 

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