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

Bill Davidsen
2004-08-12T21:00:44Z

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@tmr.com)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me