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#1
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Erasing USB flash drives?
Has anyone come across a program that quick erases a USB flash drive stick,
so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. |
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#2
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Erasing USB flash drives?
"Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Unless I'm missing your point, plug in the flash drive, right click on the drive letter and format it. -- Bruce Hagen MS-MVP Oct. 1, 2004 ~ Sept. 30, 2010 Imperial Beach, CA |
#3
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Erasing USB flash drives?
Bruce Hagen wrote:
"Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Unless I'm missing your point, plug in the flash drive, right click on the drive letter and format it. OK, my bad, I didn't explain it correctly. I want to do this on flash drives that already have data that I wish to preserve. Let me explain: I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) |
#4
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Erasing USB flash drives?
"Bill in Co" wrote in message m... Bruce Hagen wrote: "Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Unless I'm missing your point, plug in the flash drive, right click on the drive letter and format it. OK, my bad, I didn't explain it correctly. I want to do this on flash drives that already have data that I wish to preserve. Let me explain: I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) I think I understand you now. I don't know of any program. If there isn't any, use multiple flash drives. Eg: Drive 1 has 4 files A B C D. You want to save only C & D. Drag them to another flash drive (2) and format the original. Add E & F to the formatted drive and copy back C & D. Format drive 2 and so on. -- Bruce Hagen MS-MVP Oct. 1, 2004 ~ Sept. 30, 2010 Imperial Beach, CA |
#5
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Erasing USB flash drives?
Bill in Co wrote:
I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) Wouldn't any tool that wipes "free space" do what you want? There would be nothing remnant in the media in that unused space (which is where were the files that you then deleted). When you delete the file, it is no longer in the file table. That doesn't wipe the sectors that the files used that are now deleted. So you need something that works outside the file table to wipe the sectors that are now free but were previously used and may still contain data. |
#6
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Erasing USB flash drives?
"Bill in Co" wrote in message
m... Bruce Hagen wrote: "Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Unless I'm missing your point, plug in the flash drive, right click on the drive letter and format it. OK, my bad, I didn't explain it correctly. I want to do this on flash drives that already have data that I wish to preserve. Let me explain: I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) So, what happens when you try to do it with Eraser? Does it fail with an error message? Does it hang? Does it complete as if it has succeeded but the undelete program still sees the files? -- Glen Ventura MS MVP Oct. 2002 - Sept. 2009 CompTIA A+ |
#7
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Erasing USB flash drives?
glee wrote:
"Bill in Co" wrote in message m... Bruce Hagen wrote: "Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Unless I'm missing your point, plug in the flash drive, right click on the drive letter and format it. OK, my bad, I didn't explain it correctly. I want to do this on flash drives that already have data that I wish to preserve. Let me explain: I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) So, what happens when you try to do it with Eraser? Does it fail with an error message? Does it hang? Does it complete as if it has succeeded but the undelete program still sees the files? Eraser runs fine, but it just doesn't remove the file list. I use the erase (overwrite) unused space directory entries option, which works great, EXCEPT on flash drives. It's very fast and works great on most disks. (I'm not trying to go through and erase all remnants (i.e. for security reasons), which is a completely different scenario -just the directory entries. IIRC, there was actually a note on their web site (and some other sites) that admits this is a difficult task to accomplish with flash drives, due to their wear leveling routines (moving the stored "locations" around after each rewrite for wear leveling). |
#8
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Erasing USB flash drives?
VanguardLH wrote:
Bill in Co wrote: I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) Wouldn't any tool that wipes "free space" do what you want? Evidently not, at least not with these USB flash drives, as I mentioned in the other post I just sent. What isn't getting erased evidently is the FAT table as far as I can see this. (I'm not talking about any partial remnants of files on the disk which have been subsequentally marked as being available free space). There would be nothing remnant in the media in that unused space (which is where were the files that you then deleted). When you delete the file, it is no longer in the file table. That's what one would assume, and that those file tables entries are gone. That doesn't wipe the sectors that the files used that are now deleted. That's not what I need, though. (The file name entries are evidently still showing up in the FAT table when scanned by an unerase program). So you need something that works outside the file table to wipe the sectors that are now free but were previously used and may still contain data. |
#9
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Erasing USB flash drives?
"Bill in Co" wrote in message
m... glee wrote: "Bill in Co" wrote in message m... Bruce Hagen wrote: "Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Unless I'm missing your point, plug in the flash drive, right click on the drive letter and format it. OK, my bad, I didn't explain it correctly. I want to do this on flash drives that already have data that I wish to preserve. Let me explain: I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) So, what happens when you try to do it with Eraser? Does it fail with an error message? Does it hang? Does it complete as if it has succeeded but the undelete program still sees the files? Eraser runs fine, but it just doesn't remove the file list. I use the erase (overwrite) unused space directory entries option, which works great, EXCEPT on flash drives. It's very fast and works great on most disks. (I'm not trying to go through and erase all remnants (i.e. for security reasons), which is a completely different scenario -just the directory entries. IIRC, there was actually a note on their web site (and some other sites) that admits this is a difficult task to accomplish with flash drives, due to their wear leveling routines (moving the stored "locations" around after each rewrite for wear leveling). I don't think an undelete program will show you files that are recoverable if all it sees is the index, the list... but not the data itself that can be recovered. What I'm saying is, you are trying to get Eraser to just delete the file list.... that's not what is does, as I recall, it overwrites the actual data on disk. If you still see the file listed by the undeleter, then the data itself is still available. It sounds like you only want to delete the file list of names but not the data itself.... AFAIK Eraser doesn't do that in the first place. Eraser was developed primarily to overwrite the data. Are you using some other option in Eraser that purports to remove file names but not overwrite the data? I don't see why Eraser would even have that option since it is designed for security purposes to overwrite the actual data. The last time I used Eraser was over 10 years ago, so perhaps it changed, but from the readme file of that version: "Eraser is an advanced security tool, which allows you to completely remove sensitive data from your hard drive by overwriting it several times with carefully selected patterns..... The patterns used for overwriting are based on Peter Gutmann's paper "Secure Deletion of Data from Magnetic and Solid-State Memory" and they are selected to effectively remove the magnetic remnants from the hard disk making it impossible to recover the data. Other methods include the one defined in the National Industrial Security Program Operating Manual of the US Department of Defense and overwriting with pseudo-random data up to one hundred times." I don't see any mention of it having an option to remove files from the list without overwriting the data. It sounds like it is just being unsuccessful working on your flash memory for other reasons. -- Glen Ventura MS MVP Oct. 2002 - Sept. 2009 CompTIA A+ |
#10
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Erasing USB flash drives?
The default file system for removable media is FAT. There are 2 copies
of the FAT (file allocation table) to provide redundancy checking. That an old entry is in the duplicate FAT shouldn't be seen by normal apps - but then you're not using a normal app as it is not just issuing system API calls regarding FAT entries but actually digging into the FAT at a low-level to go look in the duplicate and unused copy. The 2 copies of the FAT are tightly synchronized on writes to ensure they have equal allocations of which clusters belong to which file. However, on reads, the 2nd copy is only used when error occur in the 1st FAT copy. The 2nd copy is so infrequently used that it might as well as not exist. Even disk repair tools don't use the 2nd FAT. Normally there are 2 copies of the FAT but a boot sector (byte 16) can specify the number of copies (1 or 2; default is 2). See http://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html, section 1.2, Boot Sector. For FAT12 or FAT16, only the first or primary FAT gets used and the 2nd is ignored but kept in sync. For FAT32, you could select which copy was the primary FAT. That meant you could switch between FATs if one got corrupt by changing a 4-bit value within the Flags field (never had to do that so I don't of any handy tools for switching between primary and backup FATs under FAT32). Other than a disk editor (where you can look at and edit any sector on the disk), I didn't bother searching around for tools that would let the user configure whether or not there was the 2nd or duplicate FAT copy. When you delete a file, its entry is removed from the primary FAT copy. I would've expected the 2nd copy to get updated, too, but apparently not in your case. Since you are writing to the primary FAT when removing a file's entry there, the write operation should mandate a synchronization of the backup FAT. For some reason, perhaps your FAT copies are getting out of sync. While I remember from long ago in my MS-DOS days that the 2nd FAT could be used to replace the 1st FAT if the 1st FAT got corrupted, I never had to do that. So I don't know of any tools that replace the 1st FAT with the 2nd FAT. There is mention of using a hex editor to manually sync (http://www.microswamp.com/index.php?...s/article&rn=3) the 1st FAT from entries in the backup FAT so I imagine there are tools that will automatically overwrite the 1st FAT with the contents of the backup FAT. There is some info at http://averstak.tripod.com/fatdox/bootsec.htm about the boot sector entries that affect behavior of the FAT. Search on "sync" and note the article mentions that a flag can be used to determine if the 2 FATs are kept in sync or not, how it is normally unset (zeroed) but that disk tools might set it to fix problems; however, if the bit remained set then subsequent synchronization won't occur and the FATs will get out of sync. I suppose it's even possible for tweaking every ounce of performance out of the device that the manufacturer could disable synchronization to eliminate the overhead of having to update 2 copies of the FAT during writes to the primary one. I've seen some articles talking about disk utilities or low-level commands (that bypass the system API) where they can exit with or without synchronizing the FATs. So it looks like your unerase utility is finding old entries in the 2nd copy of the FAT for files that no longer exist either because you deleted them or even after wiping free space to completely eradicate the *file* contents. As has been mentioned, formatting will wipe the drive and leave you with an empty FAT, including the 2nd one. Maybe even a quick format would create new FATs (primary and backup) since you already did the free space wipe. So it looks like the first respondent, Bruce, had the easiest answer which is to reformat the drive. A quick format might suffice since that doesn't touch the file's sectors but just wipes the file system which presumably would include the backup FAT. Otherwise, you're hunting around for utilities that can modify the backup FAT or force it to sync with the primary FAT, checking if synchronization has been disabled in the boot sector, and more super-geek manipulations. |
#11
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Erasing USB flash drives?
glee wrote:
"Bill in Co" wrote in message m... glee wrote: "Bill in Co" wrote in message m... Bruce Hagen wrote: "Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash drives, Correction: some flash drives, at least. It seems to depend on the specific instances. although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Unless I'm missing your point, plug in the flash drive, right click on the drive letter and format it. OK, my bad, I didn't explain it correctly. I want to do this on flash drives that already have data that I wish to preserve. Let me explain: I have some USB flash drives where I might decide to add some files, then later delete them, and want it to look as if I hadn't added them (i.e. a clean slate) for the next experiment. And the way I check that is: to run an unerase program to see what was left there, and what's not, and what I've just recently erased . To do this, I need the drive to appear to be cleaned (of those entries) before the next test. I guess I'm having a hard time explaining this. :-) So, what happens when you try to do it with Eraser? Does it fail with an error message? Does it hang? Does it complete as if it has succeeded but the undelete program still sees the files? Eraser runs fine, but it just doesn't remove the file list. I use the erase (overwrite) unused space directory entries option, which works great, EXCEPT on flash drives. It's very fast and works great on most disks. (I'm not trying to go through and erase all remnants (i.e. for security reasons), which is a completely different scenario -just the directory entries. IIRC, there was actually a note on their web site (and some other sites) that admits this is a difficult task to accomplish with flash drives, due to their wear leveling routines (moving the stored "locations" around after each rewrite for wear leveling). I don't think an undelete program will show you files that are recoverable if all it sees is the index, the list... but not the data Wait - nobody said anything about files that are recoverable. That wasn't my desire, anyways :-) Actually, the unerase programs typically show files that were erased and whether or not they've been overwritten (clusters), so you can get some idea of what your chances are in trying to recover them successfully or not. (If some of the clusters have been overwritten, the chances are slim, of course). I've been using "Recuva" (a nice freebie unerase/undelete program) for most of these checks). More below. itself that can be recovered. What I'm saying is, you are trying to get Eraser to just delete the file list.... that's not what is does, as I recall, it overwrites the actual data on disk. If you still see the file listed by the undeleter, then the data itself is still available. It sounds like you only want to delete the file list of names but not the data itself.... AFAIK Eraser doesn't do that in the first place. Eraser was developed primarily to overwrite the data. Are you using some other option in Eraser that purports to remove file names but not overwrite the data? I don't see why Eraser would even have that option since it is designed for security purposes to overwrite the actual data. Yes, that's what I was doing. By running it with the option to simply overwrite the directory entries, it essentially does that - wipes out the directory entries, (but, as you said, if you wanted to, you could probably still recover some file data, but that is not an issue for me). Anyways, the option is indeed there. The advantage of this option is that it does a "quick erase" of leftover directory entries, without formatting the disk and wiping out everything on it - which I don't want. (And it also makes it somewhat more difficult for an unerase program to successfully find and restore data, since the directory entries were erased - I've been around the block on that one, but that's another story :-). The last time I used Eraser was over 10 years ago, so perhaps it changed, but from the readme file of that version: "Eraser is an advanced security tool, which allows you to completely remove sensitive data from your hard drive by overwriting it several times with carefully selected patterns..... The patterns used for overwriting are based on Peter Gutmann's paper "Secure Deletion of Data from Magnetic and Solid-State Memory" and they are selected to effectively remove the magnetic remnants from the hard disk making it impossible to recover the data. Other methods include the one defined in the National Industrial Security Program Operating Manual of the US Department of Defense and overwriting with pseudo-random data up to one hundred times." I don't see any mention of it having an option to remove files from the list without overwriting the data. It sounds like it is just being unsuccessful working on your flash memory for other reasons. Well, see above. Thanks for the info. And btw, most of the time it works pretty well in that capacity - it's just a small issue for me for some drives. :-) |
#12
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Erasing USB flash drives?
VanguardLH wrote:
The default file system for removable media is FAT. There are 2 copies of the FAT (file allocation table) to provide redundancy checking. That an old entry is in the duplicate FAT shouldn't be seen by normal apps - but then you're not using a normal app as it is not just issuing system API calls regarding FAT entries but actually digging into the FAT at a low-level to go look in the duplicate and unused copy. The 2 copies of the FAT are tightly synchronized on writes to ensure they have equal allocations of which clusters belong to which file. However, on reads, the 2nd copy is only used when error occur in the 1st FAT copy. The 2nd copy is so infrequently used that it might as well as not exist. Even disk repair tools don't use the 2nd FAT. Normally there are 2 copies of the FAT but a boot sector (byte 16) can specify the number of copies (1 or 2; default is 2). See http://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html, section 1.2, Boot Sector. For FAT12 or FAT16, only the first or primary FAT gets used and the 2nd is ignored but kept in sync. For FAT32, you could select which copy was the primary FAT. That meant you could switch between FATs if one got corrupt by changing a 4-bit value within the Flags field (never had to do that so I don't of any handy tools for switching between primary and backup FATs under FAT32). Other than a disk editor (where you can look at and edit any sector on the disk), I didn't bother searching around for tools that would let the user configure whether or not there was the 2nd or duplicate FAT copy. When you delete a file, its entry is removed from the primary FAT copy. I would've expected the 2nd copy to get updated, too, but apparently not in your case. Since you are writing to the primary FAT when removing a file's entry there, the write operation should mandate a synchronization of the backup FAT. For some reason, perhaps your FAT copies are getting out of sync. While I remember from long ago in my MS-DOS days that the 2nd FAT could be used to replace the 1st FAT if the 1st FAT got corrupted, I never had to do that. So I don't know of any tools that replace the 1st FAT with the 2nd FAT. There is mention of using a hex editor to manually sync (http://www.microswamp.com/index.php?...s/article&rn=3) the 1st FAT from entries in the backup FAT so I imagine there are tools that will automatically overwrite the 1st FAT with the contents of the backup FAT. There is some info at http://averstak.tripod.com/fatdox/bootsec.htm about the boot sector entries that affect behavior of the FAT. Search on "sync" and note the article mentions that a flag can be used to determine if the 2 FATs are kept in sync or not, how it is normally unset (zeroed) but that disk tools might set it to fix problems; however, if the bit remained set then subsequent synchronization won't occur and the FATs will get out of sync. I suppose it's even possible for tweaking every ounce of performance out of the device that the manufacturer could disable synchronization to eliminate the overhead of having to update 2 copies of the FAT during writes to the primary one. I've seen some articles talking about disk utilities or low-level commands (that bypass the system API) where they can exit with or without synchronizing the FATs. So it looks like your unerase utility is finding old entries in the 2nd copy of the FAT for files that no longer exist either because you deleted them or even after wiping free space to completely eradicate the *file* contents. No, I don't think this is it. But see my note to Glen where I explained it better. The *option* I'm using with the Eraser program is under the unused disk space tab, and it's simply to overwrite directory entries, which normally does a pretty good and quick job of that (while leaving desired data intact on the drive). As has been mentioned, formatting will wipe the drive and leave you with an empty FAT, including the 2nd one. Maybe even a quick format would create new FATs (primary and backup) since you already did the free space wipe. So it looks like the first respondent, Bruce, had the easiest answer which is to reformat the drive. A quick format might suffice since that doesn't touch the file's sectors but just wipes the file system which presumably would include the backup FAT. Otherwise, you're hunting around for utilities that can modify the backup FAT or force it to sync with the primary FAT, checking if synchronization has been disabled in the boot sector, and more super-geek manipulations. |
#13
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Erasing USB flash drives?
"Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Win98/ME works Eraser; because the USB flash drive stick is FAT32 volumes.. |
#14
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Erasing USB flash drives?
000-222-000 wrote:
"Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Win98/ME works [like] Eraser; because the USB flash drive stick is FAT32 volumes.. Yes, but that doesn't explain why the WinXP defragger doesn't do it when it is defragging a FAT32 volume, while the Win98/ME one does: Both the regular Win98/ME defragger AND the the regular WinXP defragger can defrag FAT32 volumes, but only the former (the Win98/ME one) seems to erase any previously erased file table entries (that can be discovered by running an unerase program). And the defragger doesn't even have to run to completion to do that (just briefly start it, and then stop it a couple of seconds later, and that's done). (most of the *files* themselves would be unrecoverable since some of their clusters have likely been reused, but that's not the issue here) |
#15
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Erasing USB flash drives?
"Bill in Co" wrote in message
m... 000-222-000 wrote: "Bill in Co" wrote in message ... Has anyone come across a program that quick erases a USB flash drive stick, so that a simple unerase program doesn't show what files were on it? (I don't do this for security reasons, I only do it for my own convenience (when I'm trying to recall what changes I make on the drive subsequentially; it's hard to explain :-). So here is what I have discovered: "Eraser" doesn't seem to be able to do it for flash dirves, although it works well on other drives. (I'm just talking about using the basic erase options here) The WinXP disk defragger(s) don't do it, either. BUT the standard Win98/ME defragger DOES do it! And you only have to run it for a few seconds to clear traces of any file entries; it doesn't need to run to completion. Clearly the Win98/ME defrag works a lot better in that one regard (on FAT volumes) than the WinXP defragger(s) do. It somehow erases the FAT table entries, where the Win XP defraggers don't. Win98/ME works [like] Eraser; because the USB flash drive stick is FAT32 volumes.. Yes, but that doesn't explain why the WinXP defragger doesn't do it when it is defragging a FAT32 volume, while the Win98/ME one does: Both the regular Win98/ME defragger AND the the regular WinXP defragger can defrag FAT32 volumes, but only the former (the Win98/ME one) seems to erase any previously erased file table entries (that can be discovered by running an unerase program). And the defragger doesn't even have to run to completion to do that (just briefly start it, and then stop it a couple of seconds later, and that's done). (most of the *files* themselves would be unrecoverable since some of their clusters have likely been reused, but that's not the issue here) OK, apparently I misunderstood your original question/issue what you were doing with the files and what you were trying to achieve. In regard to the difference in what Win98 defrag does compared to WinXP defrag, defrag programs by different companies work differently, use different algorithms for defragging, and some do a more "complete" job than others based on what the makers decide is optimal. The Win98 defragger was made by Symantec, and the WinXP defragger is a stripped-down version of Executive Software's Diskeeper. They work in different ways, as you can see. -- Glen Ventura MS MVP Oct. 2002 - Sept. 2009 CompTIA A+ |
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