What's the difference between /dev/sg0 and /dev/sr0?

$ uname -srvmpio Linux 5.4.0-31-generic #35-Ubuntu SMP Thu May 7 20:20:34 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux $ sudo cdrecord -inq Device was not specified. Trying to find an appropriate drive... Detected CD-R drive: /dev/cdrw Using /dev/cdrom of unknown capabilities Device type : Removable CD-ROM Version : 5 Response Format: 2 Capabilities : Vendor_info : 'TSSTcorp' Identification : 'DVD+-RW SU-208GB' Revision : 'D100' Device seems to be: Generic mmc2 DVD-R/DVD-RW. $ sudo cdrecord --devices wodim: Overview of accessible drives (1 found) : ------------------------------------------------------------------------- 0 dev='/dev/sg1' rwrw-- : 'TSSTcorp' 'DVD+-RW SU-208GB' ------------------------------------------------------------------------- $ ls -la /dev/cdrw /dev/sg1 /dev/sr0 lrwxrwxrwx 1 root root 3 Mai 20 19:44 /dev/cdrw -> sr0 crw-rw----+ 1 root cdrom 21, 1 Mai 20 19:44 /dev/sg1 brw-rw----+ 1 root cdrom 11, 0 Mai 20 19:44 /dev/sr0 

So, what's the difference between /dev/sg1 and /dev/sr0? Which one to use for burning data DVDs? The machine has only one physical CD/DVD drive.

Moreover: can this drive write double-layered DVDs?

1 Answer

These are naming conventions for SCSI drivers. Below are some of the SCSI drivers:

• sd: mass-storage driver
  • sda: first registered device
  • sdb, sdc, etc.: second, third, etc. registered devices
• ses: Enclosure driver
• sg: generic SCSI layer
• sr: “ROM” driver (data-oriented optical disc drives; scd is just a secondary alias)
• st: magnetic tape driver

Source: Naming conventions - Device file - Wikipedia

Additionally, Generic SCSI just gives the guest operating system direct access to SCSI devices connected to the host. So, you're actually using /dev/sr0 for burning DVD.