Daemon tools is is a Virtual DVDROM drive (Generic DVD-ROM) enabling you to use your DVD ISO image as if it was an actual DVD. After installing Daemon Tools, if you double click on My Computer, you will see a drive letter assigned to the virtual drive. An ISO image file is an exact copy of your DVD. You can create an ISO image during the ripping process using Robot4rip. You can play the ISO image of the DVD by inserting it into the virtual DVD ROM drive and running your DVD player, such as PowerDVD or WinDVD.
This means that you could rip the movie to your computer from your ISO image.This would be useful if, for some reason, you only had access to your DVD for a short period of time and later wanted to encode and test out the DivX movie. You should always test out your DivX movie before storing away your DVD. You may find it was encoded in the wrong aspect ratio or some other unlikely problem and need to re-rip the DVD.
Another thing I should mention is the time is takes to create an ISO image. Just as an example, a 96 minute movie took me 48 minutes to rip to an ISO file, then an additional 10 minutes to rip the ISO image into VOB files. If I didn't create an ISO file and just ripped the DVD to VOB files, it took 26 minutes. My suggestion is that if all possible, rip the DVD movie directly to VOB files, encode overnight and test the movie the next morning before storing away your DVD. Remember to backup your DivX movies in case of hard drive, CD or DVD failure.
If your hard drive partition where you are saving your ISO image is FAT32, files greater than 4GB are not supported. Therefore, Robot4rip (DVD Decrypter) will split the ISO file into smaller files with the extensions of .I00 and .I01 and create a .MDS which is an index to those 2 files. What this means to you is that once your ISO (.I00 and .I01) files are created, Robot4rip will halt and give you an error that the .ISO file cannot be found. You will need to right click the Daemon Tools icon in the system tray and move your cursor to Device, then move your cursor to Mount Image .
Then go to the folder where you ripped your ISO image to. Make sure Files of type: is set to All images. Then select the .MDS file and press Open.
Then in Robot4rip, select Scan and then select your virtual DVD drive where your .MDS file is mounted.
Be sure to click on ISO Image to disable it from trying to make an ISO image of the ISO image. Then press Start to continue with the ripping to VOB files, indexing/demuxing, and audio encoding.
It's a good idea to keep your data files in a separate partition on your hard drive than your system files. It's also a good idea to keep a backup image of your system partition in case of a virus or some other Windows problem. This way you can easily and quickly restore your system.You should also have a backup of your data files on a separate hard drive or other media. You never know when a hard drive may fail! If you want to have data files larger than 4 GB, you can make your data partition NTSF, while still keeping your system partition FAT32. I have had much luck using Powerquest's Partition Magic and Drive Image to create and backup partitions (recently Symantec has acquired them.)