On Sat, 10 Jan 2004 09:46:47 -0500, alex wrote: If you want to understand, why not try yourself with something faster (and cheaper) ? Take any bootable floppy, insert it, and issue a
dd if=/dev/fd0 of=demo.img [if=input file; of=output file] Probably, demo.img will be 1474560 Bytes, whatever the floppy contained. dd creates an image; a 1:1 'copy' of all bytes on the floppy; including their allocation on the floppy. This process is reversible. Enter a fresh, unformatted floppy into the drive, issue dd if=demo.img of=/dev/fd0 and the fresh floppy is a 1:1 copy of the earlier one and even boots; since the allocation of the data on that floppy is identical to the earlier one. Try the same with zip. The zip-file will simply contain the content of that boot-floppy as files; without maintaining the locations, and be dependent in its size on the actual data on that floppy. Try to write it back to another fresh floppy, and it might complain about format; but surely it will not boot. zip has no clue where to write the boot record or know that it even existed. But the data will be back, any place. Hopefully, this clears up the concept 'image'. The demo.img (or whatever you call it; it is independent of the name !) preserves more than just the data. It mirrors the actual medium. So demo.img is an image of that floppy; the floppy itself isn't. (It contains a number of independent files somewhere on that floppy.) It rather is the real thing. Similarly, you should now be able to answer your questions about the CD and its image. .iso is simply a specific format of an image for CDs. Does this help ? -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
