Emulab FAQ: Software Setup: 64 Bit (x86_64) Fedora
A 64 bit version of Fedora is now available for use on Emulab machines that support the x86_64 instruction set which includes pc3000, pc2400c2 and pc2400w.
The 64 bit Linux kernel can run 32 bit binaries, but 32 bit binaries require 32 bit libraries to run. To enable this, Fedora supports multilib which allows both 32 and 64 bit versions of an RPM to be installed at the same time. 32 bit versions of the library are installed in lib/ while 64 bit versions are installed in lib64/. By default Fedora installs 32 and 64 bit versions of most library packages. However, to save space, all but a few core 32 bit libraries where removed from the Emulab image. If you need a 32 bit library, it may be easy to find using "yum provides", and then install using "yum install". If you add 32 bit libraries to support your application, and feel they should be installed on the standard Emulab image, tell testbed-ops.
When yum installs new packages, it will install both 32 and 64 and 64 bit version of a package unless an architecture is specifed. To specify a 32 or 64 bit version of an rpm the the following format can be used "<name>.<architecture>", (the version and patch number don't need to be specified). The architecture is generally i386 for 32 bit and x86_64 for 64 bit.
By default, rpm does not list the architecture in package listings such as "rpm -qa" which can be confusing as some packages may be listed twice. Thus, the default query format for "rpm" has been modifed as described here to avoid this confusion.