Creating CD's *.iso image
Posted on 2002-04-18
Figured, I'd run this by all experts here. Luckily, so far nothing's messed up but I wanted to get to the bottom of my problem.
Our company purchased an AOpen CRW3248 CD burner and EasyCD Creator 5 Platinum, for duplicating some rather important data. My OS is WinXP. I was charged with feeling it out... So being in such a powerful position I decided to cut a few test CD's. After all, I was told to get it down before any production stuff and of course, power corrupts people...-:) I have never burned a CD in my life.
I started with a Linux Mandrake 8.2 CD1 ISO image, that's another project I'll have to try. They (Linux people) have provided checksums for every CD, for verification purposes. I made the CD and it boots and I can see files on. I think it's OK. Then I tried to do the reverse. I read the CD (still in EasyCD) and saved the contents as an *.ISO image file. However, here's the snag. When I check the image I created for the checksum, it's totally different. I even burned the image I just created onto my second CD and that works just as well. BUT IT'S SIZE AS WELL AS CHECKSUM ARE ALL DIFFERENT.... How can this be? I was under the assumption that an *.iso image is bit-by-bit copy of original.
I asked around about this and our local IT people advised me to try different software. I then downloaded trial copies of WinISO and FireBurner. They have features to create ISO images of CD's as well.
Now I'm totally confused... Every utility I have tried produces a different size ISO file, therefore the checksums are different, too. In all my trials, I have used that same Mandrake first CD I burned as my original. I have three ISO images now, all different sizes and what's really funny, when I burned them on CD's, THEY ALL WORK. I have scanned my system for viruses and Norton thinks it's all right.
Can experts explain this? What's inside an ISO file. How can it be that different programs create DIFFERENT results from the same original that WORK???? So is it really that ALL of them are correct?