>>>>> "Jeff" == Jeff Garzik <[email protected]> writes:
Jeff> Ian Pratt wrote:
>>
>> We certainly should be pushing everyone toward using the 'xdX' etc
>> devices that are allocated to us. However, the installers of
>> certain older distros and other user space tools won't except
>> anything other than hdX/sdX, so its useful from a compatibility POV
>> even if it never goes into mainline, which I agree it probably
>> shouldn't.
Jeff> Yes, this is true. Red Hat installer guys grumbled at me when I
Jeff> wrote the 'sx8' block driver: since it wasn't hda/sda, they had
Jeff> to write special code for it, as they apparently must do for any
Jeff> new block driver "class". SuSE and other distros are probably
Jeff> similar, since each block driver provides its own special
Jeff> behaviors and feature exports.
Jeff> I should have spoken up a long time ago about this, but anyway:
Jeff> An IBM hypervisor on ppc64 communicates uses SCSI RPC messages.
Jeff> I think this would be quite nice for Xen, because SCSI (a) is a
Jeff> message-based model, and (b) implementing block using SCSI has a
Jeff> very high Just Works(tm) value which cannot be ignored. And
Jeff> perhaps (c) SCSI target code already exists, so implementing the
Jeff> server side doesn't require starting from scratch, but rather
Jeff> simply connecting the Legos.
The IA64 virtualisation work (Xen and Linux-on-Linux) uses the SKI
simulator virtual scsi device --- which looks just like any other scsi
disk, but uses hypervisor calls to do read/write/open/close calls like
a user-mode process. For performance, it needs to be extended a bit
to do asynchronous I/O and interrupt on completion. As a halfway
house, the ski simscsi driver would be fairly easy to port, I think.
--
Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au
http://www.ertos.nicta.com.au ERTOS within National ICT Australia
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
