_(Pegasus | http://www.cl.cam.ac.uk:80/Research/SRG/netos/old-projects/pegasus/pegasus1.html) and _("Pegasus II" | http://www.cl.cam.ac.uk:80/Research/SRG/netos/old-projects/pegasus/index.html), 2 *(OS)es from the University of Cambridge, whose purpose is to support applications requiring a constant quality of service _(QoS).
