If the card reader is at all functional under Linux, it will be showing
up as /dev/sda, sdb, etc., one for each card slot usually. These SCSI
disks are assigned to hardware devices in order of hardware being
encountered. If you plug your card reader in and have a SCSI hard disk
system, you can have some serious fun there. If you have other USB
storage devices, exact assignment will depend on the order in which you
plug them in. (One could argue that this design of Linux is slightly
deficient.)

If you plug a memory card in the reader and the card is recognised by
Linux, the quickest way to find out where the card is in /dev/ is to run
fdisk -l, which shows the partition tables of all visible disks. Flash
cards always contain a partition table.

Next thing you test is whether you can read data from the card in some
useful quantities. dd is the tool of choice, e.g.

dd bs=1k if=/dev/sda of=/dev/null count=20000

reads the first 20 megs or so from the card. (Also good for speed
tests.)

If there are no problems there and the card contains a valid filesystem
besides a valid partition table, you can then mount it.

> 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.
> 
> 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!

You hope wrong.

Somehow SuSE 9.1 manages to always mount the same device to the same
directory, so one can create desktop icons, but I haven't investigated
how it works. It just does.

Volker

-- 
Volker Kuhlmann                 is possibly list0570 with the domain in header
http://volker.dnsalias.net/             Please do not CC list postings to me.

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