xen-hypervisor-3.3 3.3.0-1ubuntu7.1~hardy1 (i386 binary) in ubuntu hardy

 The hypervisor is the "core" for XEN itself. It gets booted by the boot loader
 and controls cpu and memory, sharing them between your administrative domain
 (Domain 0) and the virtual guest systems.
 .
 In order to boot a XEN system along with this package you also need a kernel
 specifically crafted to work as the Domain 0, mediating hardware access for
 XEN itself. An example config file for this kernel and documentation on how
 to build it can be found in the xen-docs package.
 .
 This version of the hypervisor is built with support for systems with up to
 4GB of memory. If you have more please install the -pae version instead.