linux usb handling. Seen as SCSI?

name_in_use450 · 09-04-2004, 05:20 PM

I just want to clear some stuff up. Correct anything.

1. Linux sees every hardware device (besides pci and isa) as sdx or hdx which is SCSI and IDE??

2. USB devices are seen as SCSI.

Can USB devices that are not storage hardware (cameras, usb pendrives) be mounted? Such as an usb external wireless receiver or a joystick.

Andrew Benton · 09-04-2004, 05:44 PM

Cameras and USB pendrives are storage devices as far as the kernel is concerned. The kernel sees my camera and mp3 player as /dev/sda1. I could make udev mount them in different places but I don't plug them in at the same time so it's fine by me if it mounts them both at /mnt/mp3. However, to go back to your first point, it doesn't see every USB device as sdx or hdx. My USB printer is accessed through /dev/usb/lp0 and my modem is (I think) /dev/ppp

name_in_use450 · 09-04-2004, 08:40 PM

cool. So Parallel port printers are /dev/lp0 and usb are /dev/usb/lp0 or it doesnt matter?

Andrew Benton · 09-05-2004, 03:56 AM

I'm not sure. I know my parallel printer has always been mounted at /dev/lp0 and I used to mknod -m 660 /dev/usblp0 c 180 0 and mount my printer on that, but since I've been using udev, it mounts the USB printer on /dev/usb/lp0. I don't think the name is what counts, the kernel looks at whether it's a character or block device and whether the major and minor numbers match a suitable node. There's more detail in /usr/src/linux/Documentation/devices.txt