Protection and Relocation for the 11/25

This interoffice memorandum from Gordon Bell to the PDP-11 Coordinating Committee addresses the importance of defining protection and relocation mechanisms for the PDP-11/25. Bell argues that this issue is fundamental to all software development and suggests forming a dedicated committee to ensure the hardware design supports, rather than hinders, efficient monitor and I/O software. He specifically recommends incorporating control bits into register pairs to manage segment access (read-only, read-write, execute-only, or stack) and highlights the need for user-written I/O control programs to avoid the limitations seen in the PDP-10 monitor structure.