  Disordered jammed packings under confinement have received considerably less
attention than their \textit{bulk} counterparts and yet arise in a variety of
practical situations. In this work, we study binary sphere packings that are
confined between two parallel hard planes, and generalize the Torquato-Jiao
(TJ) sequential linear programming algorithm [Phys. Rev. E {\bf 82}, 061302
(2010)] to obtain putative maximally random jammed (MRJ) packings that are
exactly isostatic with high fidelity over a large range of plane separation
distances $H$, small to large sphere radius ratio $\alpha$ and small sphere
relative concentration $x$. We find that packing characteristics can be
substantially different from their bulk analogs, which is due to what we term
"confinement frustration". Rattlers in confined packings are generally more
prevalent than those in their bulk counterparts. We observe that packing
fraction, rattler fraction and degree of disorder of MRJ packings generally
increase with $H$, though exceptions exist. Discontinuities in the packing
characteristics as $H$ varies in the vicinity of certain values of $H$ are due
to associated discontinuous transitions between different jammed states. We
also apply the local volume-fraction variance $\sigma_{\tau}^2(R)$ to
characterize confined packings and find that these packings possess essentially
the same level of hyperuniformity as their bulk counterparts. Our findings are
generally relevant to confined packings that arise in biology (e.g., structural
color in birds and insects) and may have implications for the creation of
high-density powders and improved battery designs.
