Sparse image newbie question

[galleyleo]

I've just purchased a new 250 gig external HD to use for backing up and I have SuperDuper! installed. This is my first back-up system that I have ever used and so far it seems to be working, well, super. I'm not a very sophisticated user when it comes to technical matters, but I'm trying to learn. I'm having a hard time getting my head around the sparse image concept. I've searched for info on this, but what I read are descriptions of what a sparse disc image is and how to create one, but not it's function within ones system. I realize it's for backing up, but why is it advantageous to create?. If the image is created on the hard drive, isn't the sparse image lost in the event of a catastrophic hard drive failure? What am I missing? Please forgive my naiveté.

[dnanian]

A sparse image is a virtual disk stored in a file. It's much better to write directly to the drive if you can...

[galleyleo]

Originally Posted by dnanian

A sparse image is a virtual disk stored in a file. It's much better to write directly to the drive if you can...

After rereading the SuperDuper! Users Guide STORING A BACK UP ALONGSIDE OTHER FILES ON A DESTINATION DRIVE I am more confused than ever concerning the utility of a sparse disc image file. The Guide states..........."eventually a disaster will occur".
If so, then it would seem the disc image will be no better off than the rest of the data on the hard drive. I know I'm not getting something, but perhaps I can find more detailed information on Apple's support pages as you suggest.

Thanks

[dnanian]

But the image isn't being stored on the same drive as the original files. You want to store it on a separate drive.

[James]

The idea with a sparse disk image is that you can put it on your Backup Drive with the other files stored there, like next to your media library backup or over a network to another computer/server. You treat the sparse image just as you would a folder.

[galleyleo]

Originally Posted by James

The idea with a sparse disk image is that you can put it on your Backup Drive with the other files stored there, like next to your media library backup or over a network to another computer/server. You treat the sparse image just as you would a folder.

Ok, I get the utility in sending a file of ones hard disk to a network server for safe keeping, as I read that SuperDuper! cannot write directly to one. But this is the first time I've read specifically where to install the sparse image, which is what I have been looking for. I realize I should have taken Backup 101before asking these kinds of (stupid?) questions but as long as I've confessed to my ignorance I'll forge ahead.
Ok; you create a sparse image file (backup) of your entire hard drive to put on your say,external hard drive which already contains the backup of your computer hard drive (?) If this assumption is correct, I will pass on the other obvious questions which arise as I don't want to waste any more of your time. Thank you for bringing some clarity to this somewhat (to me) arcane subject.