At 2004-08-31T16:43:54+1200, Steve Holdoway wrote: > Just been to a customer who uses pen usb devices for backup of > specific data. Their devices ended up as /dev/sde1 and /dev/sdf1... > different ones for different makes of pen device.
The first time the kernel sees a unique device attach, it will assign it a device node (e.g. /dev/sdb). If you remove the device and plug it in again later, it will usually be assigned to the same device node. However, there are a bunch of conditions where this will not be the case, so you can't rely on it. > My worry is that they will reset after a reboot, and start counting > from sda1 ( well sdb1 in this case as there's a scsi disk in there). I > hope not! The kernel will use the first appropriate free device node, so after a reboot it will begin at /dev/sdb or whatever is the first free SCSI disk device node. Your worry is real and your backup script should deal with it. I suggest you look into a reliable method to identify the newly attached USB storage device. Since you've mentioned that you're running a 2.6 kernel, your best bet is udev[0]. udev is similar to what devfs was, but is almost completely done in userspace and allows you a large amount of control over the name of the device node that an attached device is assigned, and does so in a way that guarantees the device will always be assigned the specified name. [0] http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev-FAQ Cheers, -mjg -- Matthew Gregan |/ /| [EMAIL PROTECTED]
