Re: CD writing in future Linux (stirring up a hornets' nest)

From: Kyle Moffett
Date: Mon Jan 30 2006 - 21:02:52 EST


On Jan 30, 2006, at 17:52, Bill Davidsen wrote:
What is not easily available in Linux is a nice single place to find out what mass storage (disk/optical/floppy/ZIP/LS120/tape) devices are on the system, and what the system calls them.

Yes it is available, and a whole slew of GUI applications use it. It's called "hal", or Hardware Abstraction Layer, and it has small hooks into udev and a bit of sysfs code so that it has a list of all devices of various types and knows what their associated udev-created device nodes are. This means that I can configure udev to put my CD drive on /dev/burner and correctly written GUI programs will just find it and work.

Because for low tech users udev is the problem, not the solution. The user doesn't want to tell the system what to call the device, he wants to see what's there, and that includes serial numbers of drives (where available) because if a user has several drives it's likely that they are identical.

Your average low-tech user installing stock Debian (Not even something targeted at user-friendliness like Ubuntu), will end up with udev/hal installed. When he plugs in his burner, it will get the name /dev/cdrom[0-9] behind the scenes, and hal will notice. When he starts up k3b, it will use hal and automatically notice his drive, showing him brand, serial number, etc.

Instead of having the user tell the system what to call a device, let the system tell the user what it is called.

Uhh, both happen. The system tells userspace "I just got/have a device with brand 'foo', specs 'bar', serial 'baz', etc". Userspace (behind the scenes, without your low-tech user caring) creates a device node "/dev/cdrom[0-9]" and alerts hal, which sends it to your application, which nicely alerts the user. As an admin who does a lot on the command line, I can tie certain drive serial numbers to / dev/blue_burner and /dev/red_burner for my own ease-of-command-line- use without breaking the aforementioned hal system.

Cheers,
Kyle Moffett

--
I have yet to see any problem, however complicated, which, when you looked at it in the right way, did not become still more complicated.
-- Poul Anderson



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/