## The DragonFly virtual kernels ***Obtained from [vkernel(7)](http://leaf.dragonflybsd.org/cgi/web-man?command=vkernel§ion=7) written by Sascha Wildner, added by Matthias Schmidt*** The idea behind the development of the vkernel architecture was to find an elegant solution to debugging of the kernel and its components. It eases debugging, as it allows for a virtual kernel being loaded in userland and hence debug it without affecting the real kernel itself. By being able to load it on a running system it also removes the need for reboots between kernel compiles. The vkernel architecture allows for running DragonFly kernels in userland. ### Supported devices A number of virtual device drivers exist to supplement the virtual kernel. #### Disk device The vkd driver allows for up to 16 [vn(4)](http://leaf.dragonflybsd.org/cgi/web-man?command=vn§ion=4) based disk devices. The root device will be `vkd0`. #### CD-ROM device The vcd driver allows for up to 16 virtual CD-ROM devices. Basically this is a read only `vkd` device with a block size of 2048. #### Network interface The vke driver supports up to 16 virtual network interfaces which are associated with [tap(4)](http://leaf.dragonflybsd.org/cgi/web-man?command=tap§ion=4) devices on the host. For each `vke` device, the per-interface read only [sysctl(3)](http://leaf.dragonflybsd.org/cgi/web-man?command=sysctl§ion=3) variable `hw.vkeX.tap_unit` holds the unit number of the associated [tap(4)](http://leaf.dragonflybsd.org/cgi/web-man?command=tap§ion=4) device.