Recently i was playing with some iso files, and i was thinking - is it possible to copy a CD or DVD exactly bit by bit and save this in a file?

- Can i read everything from CD/DVD? When i read sectors from HD, i cant read anything but sectors themselves - its controlled by hardware and there is no sense in changing it.
- Since CD/DVD has no sectors but rather a spiral track, how do i even access particular data piece?

Sure: dd if=/dev/<some device> of=test.iso bs=2048. Or if you're on Windows you can make an image using some expensive software like Nero :p Just kidding, dd is now available for Windows, or so I heard.


Why, you also want to read the drive's firmware?
And "no sense in changing" what?


They do have sectors/blocks. And you can read them just like you read any other media: using your system's API or by making your own drivers.

ok, but sectors on CD/DVD are diffrent than on hdd. I cant just position head over a cylinder, and issue a read of sector.

I guess i will have to loop through every single one sector untill head is over one i want to read. Cdrom will know it because it will count passed ectors, effectivly reading all of them. Is that right?

This question might be stupid, but how do i know the sector size?
Not only on cd, hdd also? There is no mandatory 512 bytes (or 2048 bytes in dvd/cd), it can be any arbitrary value. How do i determine sector size on hdd, and how on cd? Does cd has this information in TOC?


Why lead-out is needed, especially that big? why first leadout must be larger than following?