HP has (and has had) various operating systems certified on ProLiant servers over the years, including Oracle Solaris, Oracle Linux, Microsoft Windows, Red Hat

HP has (and has had) various operating systems certified on ProLiant servers over the years, including Oracle Solaris, Oracle Linux, Microsoft Windows, Red Hat Enterprise Linux (RHEL), SUSE Linux Enterprise Server (SLES), VMware, Canonical Ubuntu, Citrix, NetWare/OES, and probably a few other software giblets. HP have also had supported hardware emulators that have been running yet other operating systems atop one of these operating systems on ProLiant, as well.