11/74 MULTIPROCESSOR MECHANICAL DESIGN REVIEW

This document details the mechanical design review for the 11/74 Multiprocessor, envisioned as a replacement for the 11/70 with extended capabilities. The review, held on January 30, 1978, outlines significant enhancements in repairability, maintainability, availability, and performance.

Key Design Features and Improvements:

• Enhanced Repairability/Maintainability: Achieved through new packaging, powered-up repairability, the ability to perform peripheral maintenance while the system is operational, consistent system configurations, improved user mode diagnostics, and reconfiguration controls. Access is facilitated by hinged 1/2-length doors replacing pop panels, spring-loaded doors with magnetic latches, and specialized key access for operators and field service. Internal components are arranged to minimize cable lengths.
• Enhanced Availability: Features N+1 redundancy (including the CPU), a well-specified operating environment, and on-line system reconfiguration. Each memory box has an independent power controller (870 PWR Controller) allowing individual shutdown, with two H7750 battery backups for memory card cages mounted on swing-out frames for easy access.
• Enhanced Performance: Incorporates CISP ("hard-wired" commercial instructions) and multi-processing capabilities, offering up to 3.6 times the speed of the 11/70.
• Packaging and Structure: The 11/74 CPU utilizes hinged doors for access to internal components and control panels, with blank panels filling spare slots. The 2-CPU multiprocessor is packaged in two "Double Width Hi-Boy" enclosures, featuring ruggedized UNIBUSS interfaces, separate 866 power controllers per bay, and dedicated cable troughs for managing inter-cab memory cables. The frame assembly itself is a redesigned "Double Width Hi-Boy" structure that includes reinforced vertical supports and a redesigned stabilizer interface, having passed shock and vibration tests.
• Component Accessibility: Memory card cage blowers are designed for front-replacement, and cables provide sufficient slack for using extender cards during module testing. CPU status LEDs are visible through the closed boot panel doors.

The document also includes a project interrelationship diagram, showing the connection between various software and hardware projects, and numerous diagrams illustrating the CPU assembly in single and two-CPU configurations (both closed and open views), the H-9060 card cage, and the detailed frame assembly.