2080 ENGINEERING FUNCTIONAL SPECIFICATION

This document is a comprehensive engineering functional specification for the 2080 system, outlining its functional characteristics, goals, and design motivations. It details the system's hardware and firmware, serving as a guide for diagnostic and software engineers.

Key aspects covered include:

• System Overview: Describes the 2080's product strategy as an upgrade path for TOPS-10/20 and for coexistence with VAX, with performance goals of 3.5-5 times a KL10E. It illustrates the CPU cluster block diagram, system configurations, and hardware organization, highlighting differences from the KL10.

• Major Components: Provides in-depth descriptions of the CPU's functional units:

  • IBOX: The instruction unit responsible for prefetching instructions and operands, managing buffers, and handling potential conflicts for speed.
  • EBOX: The central execution unit performing "real" computations using a wide microcode word and managing data stores.
  • FPA: The Arithmetic Processing Accelerator designed to speed up floating-point and integer multiply/divide operations.
  • MBOX: The central block containing cache memory, managing paging, and handling physical memory reads/writes.
  • Memory: Details the internal 64K MCS memory with ECC, its addressing, cycles, refresh, and performance characteristics.

• I/O Subsystem: Describes the microprogrammed I/O processor ("PORT"), its various interfaces (ICCS link, MASSBUS, UNIBUS, IBM BLOCK MUX, PLI, 2080 TTL Bus), and data transfer modes.

• Programming and Control: Explains Exec Mode programming, including new, changed, and discontinued instructions, virtual addressing, trap handling, and the structure of special system pages. It also covers microcode control specifications and system clock management.
• Console Functionality: Details the console's role in system bootstrap, operator support, and diagnostics. This includes console hardware (F-11 microprocessor, memory, MSU interface, serial line units, interval timer) and software functionalities (hard-core and loadable console commands, terminal handling, communication protocols, error logging).
• Reliability and Diagnostics (RAMP Features): Outlines error detection and recording mechanisms, hardware recovery, and fault isolation techniques across the system components.

The document emphasizes clarity of description and is marked as company confidential, intended for internal use by Digital Equipment Corporation engineers.