  Notwithstanding the central role of D-branes in many recently proposed string
dualities, several interesting type I vacua have been found without resorting
directly to D-brane technology. In this talk, we analyze a three-generation
SO(8)xU(12) chiral type I model with N=1 supersymmetry in D=4. It descends from
the type IIB compactification on the Z orbifold and requires only Neumann
boundary conditions, i.e. only the ubiquitous D9-branes (pan-branes). We also
discuss a large class of 6D type I vacua that display rich patterns of
Chan-Paton symmetry breaking/enhancement and various numbers of tensor
multiplets. Finally, we briefly address issues raised by the conjectured
heterotic - type I duality and by the relation between type I vacua and
compactifications of the putative F-theory.
