[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU Free Documentation License|/fdl]]."]]"""]] *Question:* Could it be possible to have a system installation where you can dual-boot using either the [[Linux]] kernel, or the GNU Hurd, so that everything but the kernel is shared? *Answer:* Given that both Linux and GNU Hurd are using the [[ELF]] binary format, this could indeed be made possible, if all programs agreed to rely on only one abstraction layer, for example the standard C library ([[glibc]]). (Additionally, for example for [[system call]]s that are not covered by glibc calls, you'd need to be able to reliably trap and emulate these.) However, Linux' and the GNU Hurd's [[ABI]]'s have sufficiently diverged, so that this is not easy to do. That's why you can't currently install a system in this way, but you need a separate installation of the userspace suited for the Linux kernel, or the GNU Hurd.