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mirror of https://github.com/open-simh/simh.git synced 2026-01-13 23:37:13 +00:00
Seth Morabito 3e0214aed0 3B2: Multiple bugfixes and improvements
- Allow 3 MB RAM configuration (previously only 1MB, 2MB, and 4MB
  configurations were allowed)
- Allow SCSI CIO card to be used under 3B2/400 emulation (previously
  it could only be used under 3B2/700 emulation)
- Improved CTC, PORTS, and SCSI diagnostic checks
- Fixed a bug in IDISK device that allowed impossible disk
  configurations

The last update is a breaking change that disables the HD161 disk
type by default, since real 3B2 hardware does not support it. The
disk type will still allowed in backward compatibility mode through
use of the "SET IDISK LARGE" command.
2025-08-17 14:19:18 -04:00
..
2022-11-10 10:47:24 -05:00

AT&T 3B2 Simulator

This module contains the source for two simulators:

  1. A simulator for the AT&T 3B2/400 computer (3b2-400 or 3B2-400.EXE)
  2. A simulator for the AT&T 3B2/700 computer (3b2-700 or 3B2-700.EXE)

Full documentation for the 3B2 simulator is available here:

3B2/400 Simulator Devices

The following devices are simulated. The SIMH names for the simulated devices are given in parentheses:

  • 3B2 Model 400 System Board with 1MB, 2MB, or 4MB RAM
  • Configuration and Status Register (CSR)
  • WE32100 CPU (CPU)
  • WE32101 MMU (MMU)
  • WE32106 Math Accelerator Unit (MAU)
  • PD8253 Interval Timer (TMR)
  • AM9517 DMA controller (DMAC)
  • SCN2681A Integrated DUART (IU)
  • TMS2793 Integrated Floppy Controller (IFLOPPY)
  • uPD7261A Integrated MFM Fixed Disk Controller (IDISK)
  • Non-Volatile Memory (NVRAM)
  • MM58174A Time Of Day Clock (TOD)
  • CM195A Ethernet Network Interface (NI)
  • CM195B 4-port Serial MUX (PORTS)
  • CM195H Cartridge Tape Controller (CTC)
  • CM195W SCSI Host Adapter (SCSI)

3B2/700 Simulator Devices

The following devices are simulated. The SIMH names for the simulated devices are given in parentheses:

  • 3B2 Model 700 System Board with 8MB, 16MB, 32MB, or 64MB RAM
  • Configuration and Status Registers (CSR)
  • WE32200 CPU (CPU)
  • WE32201 MMU (MMU)
  • WE32106 Math Accelerator Unit (MAU)
  • PD8253 Interval Timer (TMR)
  • AM9517 DMA controller (DMAC)
  • SCN2681A Integrated DUART (IU)
  • TMS2793 Integrated Floppy Controller (IFLOPPY)
  • Non-Volatile Memory (NVRAM)
  • MM58274C Time Of Day Clock (TOD)
  • CM195A Ethernet Network Interface (NI)
  • CM195B 4-port Serial MUX (PORTS)
  • CM195W SCSI Host Adapter (SCSI)