Recording design alternatives are analyzed for 100 1 Gbit/in(2):vertical and horizontal patterned media, written at 1 Gbit/s with one and two pole heads. Bit write fields, disturb fields, and switching speeds are calculated as part of a system analysis of the theoretical potential of patterned media to address possible:physics limits for conventional "featureless" continuous film media (these include thermal decay, nonlinear transition shift and transition noise, and high writer pole M-s, requirements near the limit-of known materials). The patterned media "bits" are assumed oriented vertically or horizontally by crystalline write fields before adjacent bits are incorrectly , botn anisotropy,:and smaller than 100 nm to allow single-domain, 1/2ns switching. MsHcV/kT > 500, implying thermal stability write fields before adjacent bits are incorrectly overwritten, both including media demagnetization and write head remanent fields, and nearly an order of magnitude areal density extensibility beyond 100: Gbit/in(2) with present-day head/media magnetic requirements.