On Tue, Sep 14, 2004 at 01:27:54PM -0400, Mark Lord wrote:

Here's a question for you:  like all of the other RAID drivers,
this one needs an interface to a userland RAID management GUI.

The usual method for this is to create a fake character device driver,
and use that as the interface to userland.  This is commonly done,
but is it the best way to handle such?  A /proc/ or /sys/ interface
could achieve similar goals, but without the need of a fake device.

We can go either way with this one, so lets hear some opinions on it.

Well,

* if the userland interface is 100% sending cdbs or taskfiles, then I
would prefer that Jens Axboe's "bsg" be used.  Its a chardev interface
for sending/receiving commands to a request queue.

* otherwise, I would pick either chrdev or sysfs.  if you gotta support
2.4, I guess that means chrdev.

For the rest, this driver has been around (vendor driver) since before
libata became usable, and certainly before libata existed in 2.4.xx.
The driver will eventuall need to compile and run in 2.4.20,
for customers using old Redhat kernels.   It's not there yet,
but if it were to lean more heavily on 2.6.xx stuff,
then that will be more difficult to achieve.

libata and all its drivers work on RHEL2.1 (2.4.9), and someone is
even crazy enough to be porting libata to 2.2.x ;-)

	Jeff