How does the hard drive erase data?

[NanoWarrior]

subject explains my question, how does the hard drive erase data?

 

[mikesgroovin]

The harddrive won't erase data right away. If you are deleting a bunch of files from anywhere on your disk, the system tells the drive which files in which locations you are "removing". The drive will then goto it's table and remove the file's entry (or folder's entry) and remove it from the table. This way, the drive no longer "thinks" that the removed file is still on the drive. The files actually don't even move.....they are all still on the physical drive. The file(s) get removed (or over written) when you add an application or more files to replace the area on the drive where the other files physically were. Does this make sense?? Hope it helps.

-Mike

 

[ThirtySixBelow]

A good way to think of it is like a book. All of your data is stored in "chapters" and their location is recorded in a "table of contents". When you delete something, the operating system erases the "chapter" or files location from the "table of contents". The chapter is still in the book, but it doesnt show it in the table of contents, or to the user. To actually erase the data though, you have to go and reformat the hard drive in which case the laser that reads and writes with will burn the layer of material smooth again and get out the notches that it created when you wrote data to the disk. The process is more complicated then that but for a general sense it just creates divots in the cd when you write to the disk and then smooths it back out when you erase the data.

 

[mikesgroovin]

Thanks for the analogy....sometimes, when I'm in super-geek mode (like right now), I can't analyze and taper down a thought process that might be a little more easy on the eyes....

-Mike

 

[ekÆsine]

so what that means to you is even if you empty your recycle bin, you can use data recovery software to get that data back. to permanently erase data you use disk wiping software that wipes the entire hard disk, the free space, or just certain files. disk wiping takes a long time to do.

 

[Cappy]

If you want to totally wipe the drive ( zero out the HD ) .
Go to the HD manufacture`s website and Download a Utility for the model you have .The Utility will create a Bootable Floppy . You can run several tests on the drive as well .

 

[Apokalipse]

..... or you can chuck in your OS CD and do a full format (not quick)

 

[preet2u]

..... or you can chuck in your OS CD and do a full format (not quick)

...nope this won't help ..u can still recover data very easily if u do this...

What Cappy said was more appropriate ... Just lowlevel format the drive n' then zerofill it a couple of times.. the drive data is almost unrecoverable.

 

[killians45]

a format only marks the area as useable and wipes out file info from the table. the info is still there, just marked as useable. so all those 1's and 0's haven't gone anywhere. so what you need to do is what was suggested above, and write zero's. that removes it all. instead of being marked as ready for use, it will take something like 0010 1101 etc and write it to 0000 0000... all the way through. be warned, though. you dont want to do this on an old drive (I'd say 10 years or so) since much of the HDD info is contained on it's own manufacturers partition and if you write zero's it wont know what it is. be a pain in the a$$ to fix. anyhow, for example there is first aid I think by western digital.

as was posted above, cd's are different than HDD. CD roms write and rewrite differently depending on the format. Old CDR used the burn approach. some of the later RW burners use similar approach except that there are metalic type dyes in cd itself. when the plastics melt the dyes are attracted (before the cooling sets) and are put into the groves created by the laser. yet another uses a beam to polorize special dyes in the cd under the clear coat. these do not 'BURN', but line the dyes up in a polor-nonpolorized or 'one=polor' 'zero=blank' and use the cd table to determine stop start bit and length. well, have written way to much and tend to jump around to the point where its not legible after awhile. so much crap in my head and no easy way to bring it out sometimes

 

[mjsmolko]

if ive formatted
(full format) my drive twice, should that be securer than once?