Portable and affordable assistive devices are calling necessities for the physically challenged population putting forth the requirement of designing embedded systems tuned to specific assistive applications. In this paper, we present a low footprint embedded operating system, OaSis, which forms the core of embedded devices being developed for the speech impaired, the visually impaired and those with neuro-motor disorders. The target hardware, housing OaSis and on which the applications are ported is Geode GX1-233 processor based POS-563 of Advantech. The system is presently being ported to more energy efficient ARM based platform. This system currently supports three applications: Shruti - a Vernacular speech interface, Sanyog - a Visual Communication interface and a web browser. The OaSis embedded operating system has been optimized to 90 KB and provides all the features required for the specific applications. The different modules of OaSis have been described and have been compared with other operating systems.