Aspects describe multiple interface support that provides dynamic switching between new and old interface revisions. Each of the R-number of processing pipelines are synchronized together to operate as a single very long instruction word processing core. If the number is small, media surfaces each having a low data valid rate are extracted from the volume. Means are provided for selectively moving the stop member out of engagement with the shoulder of the abutment member, for example by a rotary movement, to permit axial movement of the abutment member in the housing when it is desired to release tension in the cable. A scanner can be used to sequentially move an alignment beam from spot to spot on the retina and to move a treatment laser beam from location to location on the retina. The conduit defines a flow path for the printing fluid and has an internal cross section configured such that the surface tension of printing fluid within it favors gas bubble growth along the conduit length over radial bubble growth that would fully occlude the flow path.