Re: PATCH: cdrecord: avoiding scsi device numbering for ide devices

From: Bill Davidsen
Date: Thu Aug 12 2004 - 16:04:06 EST


V13 wrote:
On Saturday 07 August 2004 02:15, Martin Mares wrote:

Hello!


Let me lead you to the right place to look for:

The CAM interface (which is from the SCSI standards group)
usually is implemeted in a way that applications open /dev/cam and
later supply bus, target and lun in order to get connected
to any device on the system that talks SCSI.

Let me repeat: If you believe that this is a bad idea, give very good
reasons.

There is one: hotplug. The physical topology of buses where all the
SCSI-like devices (being it ATAPI devices, iSCSI, USB disks or other such
beasts) are connected is too complex, so every attempt to map them to the
(bus, target, lun) triplets in any sane way is destined to fail.


Just to add on this, how is someone supposed to distinguish between two identical USB recorders using the scanbus/X:Y:Z method? I suppose he'll have to try writting to both drives each time he replugs them instead of having /dev/cdr-red /dev/cdr-blue or something similar using hotplug/udev.

cat /proc/scsi/usb-storage/*

There is a utility (name escapes me) which allows binding of a NIC to a name by MAC address, it would be nice to be able to bind by serial number for IDE/SCSI/USB devices. However, until you do that, a simple script to create a few symlinks after discovery will solve your problem. Doesn't bug me enough to bother, but that's how.
--
-bill davidsen (davidsen@xxxxxxx)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me
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