DS3100

This document is the functional specification for the DECstation 3100 and its slower variant, the DS2100, desktop workstations, detailing their hardware subsystems and software interfaces.

The DECstation 3100 features a R2000 scalar processor (16.67 MHz, providing over 11 times the performance of a VAX 11/780), R2010 floating-point coprocessor, and R2020 write buffers, complemented by 64 KBytes of instruction and data cache. It supports 4 to 24 MBytes of parity-protected DRAM and includes integral monochrome or color bitmap graphics (1024x864 pixels) with a programmable cursor. The DS2100 is identical but runs at 12 MHz, offering slightly over eight times VAX 11/780 performance.

Key integrated subsystems and interfaces include:

• Serial Interface (DZ): A quad asynchronous serial interface for keyboard, mouse, modem, and printer, with independently programmable baud rates.
• SCSI Interface (SII): Manages SCSI bus operations, including DMA data transfer at up to 4.0 MB/s, and supports up to seven SCSI peripherals.
• Network Interface (LANCE): Provides ThickWire and ThinWire Ethernet connectivity.
• System Clock/Battery-backed RAM (RTC): An MC146818 real-time clock chip with 50 bytes of battery-backed non-volatile RAM.
• ROM: 256 KBytes for self-test and bootstrap software.
• System Control and Status Register (SYS_CSR): A register for controlling LEDs, managing system status, and diagnostic functions.
• Memory Architecture: Notably, the memory system does not support I/O device DMA, requiring software to explicitly copy data for network and SCSI operations.

The document provides detailed descriptions of registers, commands, and operational procedures for these VLSI devices, along with specifications for memory, power requirements, and video timing, for workstations designed for diskless networked, local SCSI networked, or stand-alone environments.