When files are deleted are they actually removed

[joetheghost]

When files are deleted whether it;s bi disk clean up or empty temp files on closing browser,are they actually deleted leaving Free space to be used if needed or are they covered in 0s and 1 s or otherwise marked?as this would prevent their space being used,which defeats the object of deleting them to create space.

 

[ahnilated]

No, the first block is just changed to a 00 so they can be overwritten later. Unless you actually write something over them they are still easily rebuilt.

 

[SinxarKnights]

You can even quick format a drive and the files are still there to recover if needed.

 

[clutchc]

+1^
And in Win, when they go in the trash can, they aren't even marked as deleted. They are simply not available for use until restored. Meanwhile they will not be overwriten until you empty the trash.

 

[norseman4]

In windows, when a file is manually deleted it is flagged, but it still recoverable from the recycle bin, this space is still reported as being in use. When a file is deleted from the recycle bin or through other processes the allocation of the space the file occupied is released, but the bits of the file are still recoverable with the right tools. If data is written to the file after the space was deallocated the portions of that space may be overwritten and recovery of that data is darned near impossible.

Just because there is binary data on a location on the disk, doesn't mean it can't be used for something else, and simply doing a quick format on a disk does not remove any data that you may have had on the disk. You would have to wipe the disk or unallocated space to do that.

 

[joetheghost]

My concern is that I am only interested in making sure the files are not only responding to the deleted actions but are actually releasing reuseable space on the drive to use,so when I see I have deleted 2gb of files then 2gb of space is released for further use.I was reading somewhere on this site that deleted files are covered in os and 1s and sometimes with white markers ,this indicates to the drive that the file, while marked as empty cant be used for space storage.

 

[norseman4]

I was reading somewhere on this site that deleted files are covered in os and 1s and sometimes with white markers ,this indicates to the drive that the file, while marked as empty cant be used for space storage.

Nope, if you can't see it in the folder, and you can't see it in the Recycle bin, it's gone and the space is available for anything else to use. (No matter if there are any set bits (1's) in the space the file used to use)

0's and 1's are simple our way to express if a bit is off or on, respectively. A bit is the smallest unit of data available in commercially available computers. Everything stored on a drive is made up of 1's and 0's, making the space available for other files to use does not matter what the state of the bits are in.

The File Allocation Table tells the OS what locations on the drive are being used, by what files. When you delete a file (and remove it from the recycle bin) then the OS sees that the space is now available, no matter what was on there before.