How can I eject a DVD+R in the middle of burning and continue later?
It wont work.
And I don´t see a meaning
Only Multisession allow you a continue, but you can´t burn half a file and burn other half file later
Theoretically, it should be possible with any disc drive that supports buffer underrun protection.
In theory yes
But I don´t know an OS which support half files; if you stop a copy/move the file will not bei stay, it will be erased. Maybe the checksum is one reason.
Some tools like Teracopy make a stop during a filecopy and later continue on HDD/SSD/Flash possible, but it´s hard for me to see a meaning of this.
Except you want to shutdown the PC and have almost copied a 120GB-file to a flashdrive which have a writespeed of 4,5MB/s