programmatically identify removable vs fixed drives

ahz · 08-07-2009, 04:57 PM

I need to tell apart a fixed drive (IDE HDD, SATA) vs removable drive (USB, floppy, CD-ROM, DVD) vs network (NFS/CIFS).

Looking at the device is not reliable because /dev/sdb can either be a CD-ROM on IDE interface or an IDE HDD.

The file system (ext3, vfat) is a hint, but I need a more precise method.

I'm using Python but will take advice in other languages.

TBC Cosmo · 08-08-2009, 11:23 AM

Try udevinfo as an external system program from within python.

Internal SATA:

Code:

[radar@msi-k8t ~]$ udevinfo -a -p /sys/block/sda
~
~
DRIVERS=="sata_promise"
~
~

USB Drive:

Code:

[radar@msi-k8t ~]$ udevinfo -a -p /sys/block/sde
~
~
DRIVERS=="usb-storage"
~
~

These are just examples of information you can pull out of the results

ahz · 08-15-2009, 06:25 PM

Thanks, that may be what I need. BTW, on Fedora 11 it's a little different:

Code:

$ udevinfo -a -p /sys/block/sda |grep DRIV
the program '/bin/bash' called 'udevinfo', it should use 'udevadm info <options>', this will stop working in a future release
    DRIVER==""
    DRIVERS=="sd"
    DRIVERS==""
    DRIVERS==""
    DRIVERS=="sata_via"
    DRIVERS==""

$ udevadm info -a -p /sys/block/sda | grep DRIVERS
    DRIVERS=="sd"
    DRIVERS==""
    DRIVERS==""
    DRIVERS=="sata_via"
    DRIVERS==""

jschiwal · 08-15-2009, 06:41 PM

udevinfo -q path -n /dev/sdb1
/devices/pci0000:00/0000:00:13.5/usb1/1-9/1-9:1.0/host6/target6:0:0/6:0:0:0/block/sdb/sdb1

The "usb" in the line is a good hint that it is removable.

Also check this out:
grep '[[:digit:]]' /sys/block/sd*/removable
/sys/block/sda/removable:0
/sys/block/sdb/removable:1

By the way, Python seems a popular choice for dbus and hald helper programs.

David the H. · 08-15-2009, 08:21 PM

You can get a lot of information about devices from the /sys filetree. For example "cat /sys/block/<device>/removable". 0=fixed; 1=removable.

For network shares you can always read from /etc/mtab, if the matching mount line contains nfs or cifs, you know what type of share it is.

Edit: aargh. beaten to the punch again.
(I really need to figure out which script filter is blocking that "live topic" alert from running.

).