Most of you people using the internet are using it for surfing the net. But there is also a major percentage who use the internet for both surfing and downloading files. These downloads can be from simple 2KB pictures to 4.5GB ISO s. And to do this kind of huge downloads, surely you are using a download-manager more than the simple browser file saving function. Most of us use a Download accelerator to speed up the process.
But as you already know, after downloading several days ( For some persons only), after on the completion of the file, you may discover that the downloaded file actually is corrupted and all your efforts in the past few days has been wasted. This hapens to you because of the file transfer protocol you used. If you use a single click download such as a normal download accelerators use, it uses the simple web surfing protocol (http) to download the file. This protocol is actually designed for surfing the worl wide web and therefore it doesn't guarantees the transfer of the file and it does not include a function to check the contents accuracy of the file. Therefore for secure and guranteed downloads, you must use another specified file transfer protocol such as "ftp" or "bit torrent". But there is a small glitch in it. most of the files found on the net are not accessible via a ftp-server ( or most of us don't know how to find it) and as it guarantees the file transfer , the download takes more time than a normal http transfer. and also if we take the bit torrent, it does not have the function of a download accelerator and most of the time, it's more slower than a normal ftp transfer (does not applicable if you do know how to setup it correctly). Therfore we need a alternate method to securely download our files.
The answer is a combination of two above mentioned methods. (http + bit torrent). first you can use a normal download accelerator to download the file as speed as possible , without thinking of the accuracy of the file. Then after you have finished, check the file using a Hashing algorithm such as "md5" to verify it. (Those who doesn't know anything about a hashing algorithm, just run the file and check if it works). If it works correctly, then you don't need another step. you are done. but if the file is corrupted or damaged, then go to the next step.
Then you discovers the file is corrupted and you have to download it again. At this point don't download it again. Just Google the file name and the word "torrent". it will direct you to a torrent file to the required file. for this example , the same page i downloaded the fedora direct download file has the torrent file also. Then use a torrent client such as utorrent to download the the same file . But wait ! you don't need to download the same file again. just wait till the utorrent creates the file (allocate) in the hard drive and stop the download.
Go to the file allocated location and check weather the file "Fedora-8-i386-DVD.iso" is allocated again as a new file. Then you just have to Overwrite this existing blank file with your previously downloaded corrupted file. Make sure the two files are same (or this wont work).And then go to the torrent client and restart the file downloading process and observe the magic. Torrent client will find the existing file is already downloaded and will hash check with the original file's hash from the server and will find the missing parts in the whole file.
After it completes the check, it will starts to downloaded the remaining to download parts and will complete the file in no time. When this download completes, the file is guaranteed as a fully functional file.
This methods has brilliantly worked for me and saved me several times. Only glitch is that you have to find a torrent file that has the same file as yours. But What the hell, the best file sharing method currently is "bit torrent". so no worries. the file will be there.
This trick was found by me from a Blog post. But now I can't remember which one. So the whole credit goes to the person who originally posted this trick. If you are the guy, who originally posted it, just place a comment and I'll add your name to the post.
Tuesday, February 05, 2008