Why we need CD Image File!

vijay.gupta, It is somewhat difficult to answer questions that are about general understanding of concepts and principles. Why? Because often the concept or principle is potentially quite complicated. And also because the helper does not know how deep the questioner wants to get into the topic, nor at what level the questioner is starting. It is much easier to respond to questions that describe what the questioner is attempting to accomplish. For instance: Can you tell me all there is to know about .iso formatted information? <– difficult and complex type of question to respond to in a forum setting especially if we don't know what the questioner is trying to accomplish. I want to make back-up copies of all my music files. What file format should I use. Should I try to compress (zip) the files? Is there any advantage in using an .ISO type file? <– This is still a big question but at least helpers can understand what the questioner is trying to accomplish, and can give examples. I hope you will consider including an "example" of what you wish to accomplish, when asking your questions.

vijay.gupta, Consider thinking about your question this way. What follows is not "technically precise" but may offer a conceptual way to think about the topic. When a user is composing or editing a text document, the document is considered "the file" that is being worked on. It may be in file format .txt, .rtf, .doc, .dox, .pdf, .wpd, .odf, or one of many others. For this discussion I will use .doc (from MS Word 2003) If you "save" the document to a CD, what you get is: >>TheFileName.doc<< the CD may also include "attributes" like "read-only" and date of creation/last saved. _______________— But there is much more information about the .doc document as it resides on the user's computer. ______________ Much more you say? Yep. When working on a .doc document, it is "surrounded" by Microsoft Office Word, the application And Microsoft Office Word is "surrounded" by the Windows Operating System (win XP, Vista, Win7, etc.) And Windows Operating System is surrounded by BIOS Basic Input Output System instruction that tells it where to find the CPU, RAM, Hard Drive, optical drive, etc. And There is a comprehensive list of locations/maps plus required functions, called The Registry The Registry gives a sort of "street map" to an application such as MS Word, telling Word where to find stuff, when it has to stop at an intersection, how to gain access to a printer, where to save a document, where to find a document that has already been saved, and how Word can interact with other application programs and the computer itself. And There is a user login repository (c:\documents and settings\username\… ) that keeps documents belonging to one user separate from documents belonging to other users, and also allows for specific user preferences, settings and such And There is a hidden Master Boot Record that instructs the computer were to find stuff and keep it sorted by boot.ini and environment, and make it possible to "turn on" the machine to view and work on a specific file. ___________________ Now remember from above… if you save the document.doc to a CD, what you get is "the saved file.doc plus a few attributes" If however, you create a "drive image" (iso) of your C:\ … You will definitely have "saved" your document.doc, but in the process of creating the Drive Image .iso, you will also have captured all the above information and more. That might help when trying to understand what it means when the previous author refers to saving things byte by byte. I can't truly speak for what those others meant by their words, but guaranteed they had in mind including much more than just the document.doc file. ______________ If you are wanting to save your music files… Save the files in their original format. If you want to save a "backup"of your music files your can also use a compression utility such as Winzip, 7zip, rar, etc. If you are wanting to create a CD that will play in your auto stereo, or a CD/DVD player, then you will have to read up on what file formats that specific hardware will accept. Hope this helps a bit. Best Regards