再和eveline 和辣妹討論recover deleted file in Unix operating system

對於辣妹是否有錢， 是否真的辣， 我一點都不關心， 因為那與我無關。 但對於hacker是否可以hack in 一個 web application， 去recover deleted files， 我比較關心， 所以昨晚用了幾個小時去辯論， 今天早上還和我LG 討論這個問題。

辣妹說：
If a hacker can get into the database which hosts images, that means he can get that particular image eventually.

Also if the image is cashed in any other website like google engine, that is also accessible by other users.

Delete is a user function that does or does not do what the end user thinks it is doing.

看了上麵的話， 我真的感到很驚訝。 因為， 我知道在大型係統裏， image files 都是放在server 的file system裏的。 database 放的隻是 file reference。 而且， 那個server， 也不是你家裏的PC， 可以那麽容易找到那些free space 去recover data的。

下麵看一下專家是怎樣說的
Recovering Deleted Files in Linux/UNIX:

Many people think that recovering files in Linux is not possible, this is not true. It is not impossible to recovery deleted linux files, it is just rather difficult and not always successful. Unlike Windows it is much harder to recover files that have been accidentally deleted in Linux. UNIX based systems assume the user is more advanced and places more responsibility on the users to make sure their are correct. While in Windows you have the simple recycle bin, and then the ease of searching for deleted files by name and recovering them things are more complicated in Linux and there is no true undelete utility. The best policy is a very good backup policy, however when that does not happen you still have an opportunity to recover the files.
Limitations on Recovering Deleted Linux/UNIX Files:

Unlike in Windows deleted files do not retain their names or extensions so it can be difficult to find the necessary deleted files that you want back. Using the correct software you will be able to find deleted files by file size and date of deletion so it is possible to narrow down the possible files that you need. It is also important to recover the files as soon as possible because once the space that the file had occupied is overwritten is gone forever (the same goes for files deleted in any operating system).

ttp://www.datarecoverypros.com/linux-deleted-files.html

除了上麵所說的難處以外， 放照片的網站， 並不是隻是為一個人服務的， 在一個user delete file 的同一分種內， 別的users也很可能會add 他的file， 那這個user 原來的data 就會被overwritten 了， 這樣無論hacker有多天才， 也隻能望那被over written 的space 輕歎了

這個問題說來說去， 我也真累了， 就此打住吧