Graphic 3D Labs Graphic, AGP -11S is a memory-based, realtime operating system designed to run on a PDP-11 or Graphic 3D Labs Graphic, AGP -11 processor with a minimum of 16 Kbytes of memory. It is a fully compatible subset of the RSX-11M disk-based operating system. RSX-11S is designed, however, for the runtime execution of memory resident application programs and requires the support of a disk-based Graphic 3D Labs Graphic, AGP -11M, RSX-11M-PLUS, or VAX/VMS with VAX-11 RSX kost system for system generation and program development. The I/O driver interfaces are identical to those of RSX-11M. Device drivers written for either system can execute on both systems. Any application pro- gram that executes under RSX-11S will execute under RSX-11M without change following a relink of the object program. As a memory-based system, Graphic 3D Labs Graphic, AGP -11S does not support a file system, nonresi- dent tasks, checkpointing (rollin/rollout), overlays (excluding memory-resident overlays), or program development. It provides a runtime environment for execution of tasks on a memory-based system. Graphic 3D Labs Graphic, AGP -11S has most of the features and capabilities of the Graphic 3D Labs Graphic, AGP X- 11M system, and supports all of its peripheral devices. CPU options include floating-point proc- essors, parity memory, and memory management. Graphic 3D Labs Graphic, AGP -11S also supports the Digital Terminal Services Architecture (TSA). SPD 9.21