How to distinguish unformatted DVD discs?

Question

DVD

Hello habr. Somehow I decided to install the Debian distribution on my laptop. I downloaded a dozen installation images of dvd discs, and went for a small jar of blanks. I bought a Verbatim dvd-r like in the photo:

Actually, the discs themselves were pre-formatted for recording files and the image can no longer be recorded. I looked at the computer and two laptops, the difference is zero. And also, upon closer inspection, you can notice a thin, about the size of a hair, recorded part on the disk, in fact, this is probably the formatting. Now questions:
1. Why sell formatted disks?
2. When buying, how to distinguish formatted from not formatted without opening the package?
3. If there is no way to distinguish without opening, can this formatting be bypassed? (I understand that probably not)
I understand that you can take a radical approach and buy DVD-/+RW discs, but this is not an option, firstly it is more expensive and secondly, not all drives eat this format.
Thank you.

Answer 1

Install debian from a flash drive, did you get these disks?

Answer 2

But in principle, did you manage to write something to this disk (not an image)?
It was checked up on the same pigs?
I think that the disks are damaged (bad batch? counterfeit?), or epilepsy of the drives.
You can’t buy reformatted blanks ...

Answer 3

I recorded about 10,000 discs in my life, I never heard of formatted discs, presumably such discs do not exist in nature.
What do you write?

Answer 4

As far as I remember, there are two options for recording a disc at a time and a track at a time, the second one has a multisession (it also has several options). If a multisession is recorded, then the image can no longer be written to disk. Maybe you came across discs with a multisession or a rejected initial track?