**Note:** This is an overview for device-handling in QubesOS. For specific devices ([block], [USB] and [PCI] devices), please visit the respective page.
**Important security warning:** Device handling comes with many security implications! Please make sure you carefully read and understood the **[security considerations]**!
----------------------
The interface to deal with devices of all sorts was unified in Q4.0 with the `qvm-device` command and the Qubes Devices Widget. In Q3.X, the Qubes VM Manager dealt with attachment as well. This functionality was moved to the Qubes Device Widget, the tool tray icon with a yellow square located in the top right of your screen by default.
There are currently four categories of devices Qubes understands:
Microphones, block devices and USB devices can be attached with the GUI-tool. PCI devices can be attached using the Qube Settings, but require a VM reboot.
When clicking on the tray icon (looking similar to this: ![SD card and thumbdrive][device manager icon] several device-classes separated by lines are displayed as tooltip. Block devices are displayed on top, microphones one below and USB-devices at the bottom.
Click the tray icon. Hover on a device you want to attach to a VM. A list of running VMs (except dom0) appears. Click on one and your device will be attached!
To detach a device, click the Qubes Devices Widget icon again. Attached devices are displayed in bold. Hover the one you want to detach. A list of VMs appears, one showing the eject symbol: ![eject icon]
Only `mic` should be attached to more than one running VM. You may *assign* a device to more than one VM (using the [`--persistent`][#attaching-devices] option), however, only one of them can be started at the same time.
But be careful: There is a [bug in `qvm-device block` or `qvm-block`][i4692] which will allow you to *attach* a block device to two running VMs. Don't do that!
The `list` action lists known devices in the system. `list` accepts VM-names to narrow down listed devices. Devices available in, as well as attached to the named VMs will be listed.
The `attach` action assigns an exposed device to a VM. This makes the device available in the VM it's attached to. Required argument are targetVM and sourceVM:deviceID. (sourceVM:deviceID can be determined from `list` output)
`attach` accepts two options:
-`--persistent` - attach device on targetVM-boot. If the device is unavailable (physically missing or sourceVM not started), booting the targetVM fails.
-`--option`, `-o` - set additional options specific to DEVICE_CLASS.
The `detach` action removes an assigned device from a targetVM. It won't be available afterwards anymore. Though it tries to do so gracefully, beware that data-connections might be broken unexpectedly, so close any transaction before detaching a device!
