Abstract: An improved technique for processing IO requests has been described that distinguishes bogus IOs from genuine IO request failures by accessing a hardware configuration record that associates available paths with hardware components at different hardware layers traversed by the paths. When an IO request fails down a first path, a second path is selected for retrying the IO request by accessing the hardware configuration record and identifying a path that the record indicates traverses hardware components that are different from those traversed by the first path at multiple hardware layers. The chance that an IO request will fail due to faulty hardware over both the first path and the second path is thus low, such that IO failures down both the first path and the second path provide a clear indication that the IO request is bogus.

Abstract: An apparatus for installing a recessed smoke detector within a surface so that when installed, the smoke detector is substantially completely hidden from view and flush with said surface. Two mounting plates are attached to opposite sides of a housing. A pair of mounting clips attached to a cover are insertable, respectively, into slots in each of the mounting plates. The smoke detector is attached to the cover. The cover has the appearance of a loudspeaker-like grille or other similar device so that smoke can enter through apertures to reach the smoke detector. The cover after mounting is substantially flush with a surface, such as a ceiling. With the smoke detector substantially completely recessed within a surface and the cover connected to the housing, the smoke detector is substantially completely concealed, and protected from vandals and tamperers. The apparatus is easily installed, which is an important advantage with the increased need for smoke detector installation.