  We present a neutron scattering analysis of the structure of the smectic
liquid crystal octylcyanobiphenyl (8CB) confined in one-dimensional nanopores
of porous silicon films (PS). The smectic transition is completely suppressed,
leading to the extension of a short-range ordered smectic phase aligned along
the pore axis. It evolves reversibly over an extended temperature range, down
to 50 K below the \textit{N-SmA} transition in pure 8CB. This behavior strongly
differs from previous observations of smectics in different one-dimensional
porous materials. A coherent picture of this striking behavior requires that
quenched disorder effects are invoked. The strongly disordered nature of the
inner surface of PS acts as random fields coupling to the smectic order. The
one-dimensionality of PS nano-channels offers new perspectives on quenched
disorder effects, which observation has been restricted to homogeneous random
porous materials so far.
