Countdown with 22 hours, 21 minutes, so by tomorrow morning I should know if the results are good.
So far almost 5 TB searched, 511,929 photos, 13,171 video, 56,752 audio, 86,88 documents and 68 archives, whatever that is. ?
I¡¯m banking on Lee¡¯s explanation of how such software counts digits, otherwise I¡¯m going to really have a surprise tomorrow. ?like a photo that shows an aberration the naked eye can¡¯t see.
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Thank you Lee for the excellent explanation!?
John
On May 11, 2023, at 4:54 PM, Lee Larson via <leelarson@...> wrote:
?
On May 11, 2023, at 2:04 PM, John Robinson via <
profilecovenant@...> wrote:
It¡¯s DiskDrill, such a prize, it¡¯s finding more items than the original¡this freaks me out, so I have NO idea what is going to happen when it¡¯s completely done. ?So far right at 3tb of the total 8tb. ?It¡¯s found 158,542 photo¡¯s, 6,299 video, 26,267 audio, 83,903 documents and 53 archives.
Tell you what, those are not the real numbers. ?Right now I still have 39 hours of DISCOVERY, once that is done there is a button for RECOVER ALL that I tag and then the truth of how good this is. ?I didn¡¯t have near those numbers but I don¡¯t know it counts.
Most such programs I¡¯ve seen recover many fragments of deleted files along with whole files. This is a result of how they work.
In the very simplest cases, the directory of a disk contains a list of files on the disk. Along with the file name and some meta-information is the address of the first sector of the file on the disk. The directory also contains a table of contents showing which sectors on the whole disk are used and which are free. When you format a disk, the file name and meta-information is deleted and the table of contents is changed to show all the sectors are unused.
The actual file on the disk is a string of sectors in which each sector contains pointers to the previous and next sector of the file. In particular, the first and last sectors are marked as such. Recovery programs sift through all the sectors on the hard drive looking for these first and last sectors. When it finds one, it can then go forward or backward in the sector list to recover the whole chain of sectors for a file.
There are at least two problems with this method.
First, when a file is deleted from the drive, its information is deleted from the directory and the sectors for that file are marked as free in the table of contents, but the sectors themselves aren¡¯t rewritten. When a new file is written to the disk, it may use sectors from the deleted file, but the first or last sectors of the deleted file may not be touched. The recovery program will see these old first or last sectors and then spend fruitless time trying to recover the original chain of sectors, failing because the chain has been broken in the middle by the new file.
Second, if a file had previously been deleted and none of its sectors has been reassigned, then the program will resurrect a ghost file. It may end up finding several older versions of a file that¡¯s been repeatedly edited and saved.
Painstakingly going through a large hard drive and reconstructing the chains takes a long time.
With SSDs, recovering files is often hopeless because the operating system regularly tells the drive to zero out freed-up sectors. Remember the hubbub about the TRIM command when SSDs first came out? That¡¯s what this was all about. It¡¯s doubly important to back up SSDs.
I¡¯ve had to resurrect disks a couple of times and that¡¯s why I¡¯m kind of fanatic about backing up by stuff.
Good luck!
L^2
?Text processing has made it possible to right-justify any idea, even one which cannot be justified on any other grounds.¡ª?J. Finnegan
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