"XenSource and Virtual Iron, two companies trying to profit from
adoption of open-source Xen virtualization software, announced free
new versions of their products on Monday.
"XenSource's release is XenExpress. Like the company's flagship
XenEnterprise software, it lets multiple operating systems run
simultaneously in separate compartments, called 'virtual machines,'
on the same server. Unlike XenEnterprise, however, it allows people
to manage only one virtual machine at a time..."