Hi, Brian wrote: > Isn't /dev/sg0 the block device?
/dev/sgX are character devices. https://tldp.org/HOWTO/SCSI-Generic-HOWTO/intro.html says "The driver's purpose is to allow SCSI commands to be sent directly to SCSI devices. [...] Various specialized applications for writing CD-Rs and document scanning use the sg driver." This is still the case for optical drives (sr) and hard discs (sd) which get an sg device file additionaly to their block device file. But it seems that the statement about "document scanning" could need an update. The main call for sg devices is ioclt(SG_IO) which performs a single SCSI command transaction. Since about 15 years it is possible to use it directly with a /dev/srX device file. But a bug introduced in a late version of kernel 2.6 prevented concurrent use of SG_IO on multiple sr devices. This ended with https://github.com/torvalds/linux/commit/51a8588 which i assume went into kernel version 5.6. So with the currently released Debian versions, /dev/sgX is still of use if there is more than one sr device. Have a nice day :) Thomas
