How to delete WITHOUT possible recovery?

[Phoebus]

Hi.

I was just wondering if there is any sure way to delete data either from within windows or dos without being possible for that data to be recoverd (using no external software).

Thanks!
Phoebus

[condor]

depends on wht level of recovery..

for undelete programs if you delete a file and then write to the disk (save another file with the same name / defrag) it almost 100% unrecoverable..

anothre option is to use a "sherdding" util it deletes better by writing on the data area.

if you're talking about experts in recovery those will not help - the only good protection is Evidence Eliminator..

[Phoebus]

Does the /u command (format) still work? I mean if I " format /u " will it still be possible for data to be recovered?

[antonye]

Most data can be recovered by viewing the raw data on the disk because Windows does not actually delete files, it just destroys the pointer to the file.

The best way to completely remove these files is to use a "secure delete" utility. Most work in the same way by writing random data over a deleted file or disk area which then makes it impossible to retrieve any deleted files. There is even a Department of Defense standard for doing this!

Have a search on Google ("secure delete utility windows") or try SDelete which is a Freeware (with source) utility that does exactly this.

[Mr_Miyagi]

Originally posted by Phoebus:
<STRONG>Does the /u command (format) still work? I mean if I " format /u " will it still be possible for data to be recovered?</STRONG>

/U just doesn't save undelete info... you know, that annoying thing that happens when you format a floppy and find you've lost 200 kb of space!!!!
<IMG SRC="smilies/wink.gif" border="0">

[Phoebus]

Hi and thanks for replying.

Yes, I know that using external programs this is easy to do. What I'd like to know is whether or not it is possible to do this WITHOUT using any other software. Just Windows or DOS.

Thanks!
Phoebus

[Phoebus]

Oh yeah, one more thing about the format option.

If I use " format /q /u " will it make it easier for the data to be restored?

[lysergic]

If you just format then you can use a util like recover 98 to recover almost all the data (found out the hardway when an a: prompt was really a c: prompt)

Don't know if you would consider this a dos app, but there is always a low level format. Or just use norton disk doctor for dos. Have seen that scramble more drives then any other program.

[Stalemate]

Originally posted by EtOH:
<STRONG>If you just format then you can use a util like recover 98 to recover almost all the data (found out the hardway when an a: prompt was really a c: prompt).</STRONG>

THAT sucks <IMG SRC="smilies/mad.gif" border="0"> Bet you won't do it again though!

Originally posted by EtOH:
<STRONG>
Don't know if you would consider this a dos app, but there is always a low level format. Or just use norton disk doctor for dos. Have seen that scramble more drives then any other program.</STRONG>

Most drives do not support the LLF. You might try an older BIOS to see if this option can still be used, but you're playing with fire. The hassle isn't worth it.

Condor's suggestion,

for undelete programs if you delete a file and then write to the disk (save another file with the same name / defrag) it almost 100% unrecoverable..

sounds like a good idea for specific files. If Condor says it... <IMG SRC="smilies/wink.gif" border="0">

What I usually do with a hard drive that just cannot be allowed to fall into the hands of a resourceful infromation seeker, is simply to give it a good bashing with a rubber mallet. Dropping it against a concrete floor will also work.

Of course, if you still wanted to USE the drive, this might pose a problem. In my current environment, it is cheaper to trash a drive and purchase a newer (and bigger) one than to spend the time using a product like Evidence Eliminator (although it does do its job very well).

[ShadowKing]

Condor is right (as usual) the only way to delete and have it be unrecoverable without 3rd party software is to delete the file and then do a defrag... Even if you save a new file to that folder, it won't necessarily erase that portion of the disk...

[Mr_Miyagi]

Originally posted by Phoebus:
<STRONG>Oh yeah, one more thing about the format option.

If I use " format /q /u " will it make it easier for the data to be restored?</STRONG>

/q = quick, i.e. just reset partition tables
/u = dont save "unformat info"

there u go! <IMG SRC="smilies/eek.gif" border="0">

[Platypus]

Originally posted by Phoebus:
<STRONG>Hi and thanks for replying.

Yes, I know that using external programs this is easy to do. What I'd like to know is whether or not it is possible to do this WITHOUT using any other software. Just Windows or DOS.

Phoebus</STRONG>

I haven't investigated Windows' filehandling to know about it, but in real DOS (6.2 or earlier) copying another file over the one you want to destroy should do it. As far as I know, DOS just uses the same File Allocation Chain, thus writing the new file contents over the top of the old, and if the new file is larger, it just moves the EOF(End Of File) pointer and adds in the new clusters. This is not to say that's what Windows' "DOS" does, especially if FAT32 is involved. Be cautious, DOS before 7 won't work on FAT32 and knows nothing about long filenames, and will leave them orphan if you delete files with DOS 6 or earlier. (Scandisk will fix it)

The file can then be deleted, and if it is recovered with say Disk Doctor, it contains the later irrelevant file you copied over it. Also remember, if the filename could convey any information, it will still be almost complete in the directory. Before deleting the overwritten file, rename it to a single character. DOS pads filenames to 8.3 with spaces, obliterating the original filename. Then when you delete it, the single character is overwritten by DOS with the free file character. None of these measures would be effective against professional data recovery, but should prevent someone from undeleting a sensitive file.

Quote: If I use " format /q /u " will it make it easier for the data to be restored?

On a floppy disk, yes. The /Q switch means just the file system (FAT & file directory) will be renewed, all the data will be unchanged on the disk until new files are written over it.

On a hard disk it won't make any difference, the format doesn't overwrite data anyway, the /Q switch causes the drive to not be verified.

[3D Prophet III]

format ?: /q - quick format(DOS doesn't verify the disk)

format ?: /u - unconditional format(meaning fully formatted nothing saved, a ready to use disk)

format ?: /s - fully formats and will create a system boot disk if done on drive A: if done to drive C: it will put system files onto hard drive allowing you to get a C: prompt if done using a boot disk (floppy).

If you want to delete files and eliminate any possibility of recovery, defrag, delete and defrag. Install a large game, defrag again. Once you've done that only a professional could recover them files, maybe.
<IMG SRC="smilies/biggrin.gif" border="0">

[3D Prophet III]

Originally posted by Phoebus:
<STRONG>Does the /u command (format) still work? I mean if I " format /u " will it still be possible for data to be recovered?</STRONG>

By you or me, no. Professionally done, yes! The only true way to totally clear a drive of all information is to write zero's to it!
But there isn't a utility in dos or win98 that does this unless you have norton utilities or some other second party software.

[Danger]

This won't be any help, but it is related to the topic. At the store where I work we occasionally get used computer equipment in from the State of Michigan. They sell it to us, we sell it to customers. Well, we once got a laptop that had it's entire partition removed. Just out of curiosity we ran a data recovery program on it, an lo an behold, everything came back. But the interesting part was what came back. On that hard drive was the info for the traffic light system for the city in which the store is located! It had all of the codes, and the number to call, to change ANY of the trafic lights in the entire city! <IMG SRC="smilies/smile.gif" border="0">

Of course, fearing what might happen if we actually used any of that info, we got rid of it.

But I still get a kick out of that every now and then.