Abstract: A failover guaranty estimator module performs a proof by contradiction method showing that a cluster failover guaranty can be met for the cluster. For potential failures for which failover is guaranteed, the method assumes a particular host set of one or more hosts fails, leaving one or more working hosts. The method performs a per-failure host set method for the failure host set. The per-failure host set method determines an amount of memory usage within each working host of the assumed working host set that would guaranty that a largest of the virtual machines in the failure host set would be orphaned. The per-failure host set method determines if the virtual machines in the failure set, other than the largest virtual machine in that set, would force the determined amount of memory usage within working hosts, resulting in, the failover guaranty not being met.

Abstract: A failover guaranty estimator module performs a proof by contradiction method showing that a cluster failover guaranty can be met for the cluster. For potential failures for which failover is guaranteed, the method assumes a particular host set of one or more hosts fails, leaving one or more working hosts. The method performs a per-failure host set method for the failure host set. The per-failure host set method determines an amount of memory usage within each working host of the assumed working host set that would guaranty that a largest of the virtual machines in the failure host set would be orphaned. The per-failure host set method determines if the virtual machines in the failure set, other than the largest virtual machine in that set, would force the determined amount of memory usage within working hosts, resulting in, the failover guaranty not being met.

Abstract: This invention relates to systems and methods for wireless and wired optical data communications, in particular infrared data communications using techniques borrowed ultra wideband (UWB) radio. An optical data communications receiver for receiving data encoded using optical pulse position, the receiver comprising: an optical signal reception device; a reference signal memory for storing a reference channel response signal; and a correlator coupled to said reference signal memory and to said optical signal reception device for correlating a received optical pulse with said stored reference channel response signal to determine said optical pulse position; an output coupled to said correlator to provide pulse position data for said received optical pulse.

Abstract: This invention generally relates to ultra wideband (UWB) communication, and in particular to methods and apparatus for enabling such communication.

Abstract: A clear air device to maintain the cleanliness of air in "clear rooms" and to ventilate said rooms has a casing with an air inlet grid and an air outlet grid, a preliminary filter, a ventilator and a high efficiency particulate air filter unit (HEPA). The preliminary filter, the ventilator and the high efficiency filter are arranged within the casing in such an order that the air drawn in through the inlet grid first passes said preliminary filter, then the ventilator and thereafter the HEPA. The wall of the casing is provided with one opening between the air inlet grid and the preliminary filter and one opening between the HEPA and the air outlet grid.