scsi emulation and the future

[bs_texas]

I'm just curious about the use of SCSI emulation for IDE ATAPI devices.

Was this simply a hack to get things working? I guess we have to assume that it was.

Is anybody aware of any specific work being done to eliminate this need for emulation?
Will future kernels or modules replace this emulation with 'native' (or whatever) modules for devices which currently have to emulate SCSI?

I am just curious what people think and know about this issue?

regards...

[DMR]

Originally posted by bs_2003
I'm just curious about the use of SCSI emulation for IDE ATAPI devices.

Was this simply a hack to get things working? Yeah, pretty much.

Originally posted by bs_2003
Is anybody aware of any specific work being done to eliminate this need for emulation?
Will future kernels or modules replace this emulation with 'native' (or whatever) modules for devices which currently have to emulate SCSI?A few months ago I ran across a link which said that native ATAPI support for CD burners was in the works, but I haven't been able to find out much more on the issue- guess it's time for a bit of Googling...

[AdaHacker]

I hate to say it, but RTFM. The particular FM I'm thinking of is (on my system) /usr/doc/cdrtools-2.0/README.ATAPI. That document was written specifically to answer your question.

Basically, the cdrtools people blame the Linux kernel maintainers for not writing good IDE drivers. Apparently, ATAPI drives do provide native support for SCSI commands over IDE without emulation. The Linux kernel IDE drivers, however, do not support this.

[JesseJames]

I think this is actually the same in Windows aswell because I had to FORCE SCSI drivers onto my computer for ASPI to use them when ripping CD's and doing various other things.
http://aspi.radified.com/

[bwkaz]

I remember reading somewhere that SCSI emulation on kernel 2.5 was currently broken. But this was OK, because you don't need it anymore. ;)

Wish I could remember where that was...

Ah, here we go -- at least, this is the place that says that you don't need it, as of 2.5.44:

http://www.linux-sxs.org/administration/25xconf.html

And here is the original place I read about all of that:

http://lwn.net/Articles/14125/

[DMR]

Originally posted by AdaHacker
I hate to say it, but RTFM. The particular FM I'm thinking of is (on my system) /usr/doc/cdrtools-2.0/README.ATAPI. That document was written specifically to answer your question.

Basically, the cdrtools people blame the Linux kernel maintainers for not writing good IDE drivers. Apparently, ATAPI drives do provide native support for SCSI commands over IDE without emulation. The Linux kernel IDE drivers, however, do not support this. Yeah, I didn't really want to dig in to that feud, but you're essentially right; although the full SCSI command set isn't implemented in the ATAPI spec, enough of it is.


Anyway- bs_2003,

I found the info we were looking for; it looks like (at least experimentally) direct ATAPI CD-RW support is a reality. It goes along with the info that bwkaz gave; the details are here (http://freshmeat.net/releases/107625/).