simh-testsetgenerator/3B2

AT&T 3B2 Simulator

This module contains a simulator for the AT&T 3B2 Model 400 microcomputer.

CAUTION: The simulator is under active and heavy development. It is usable today, but please consider this emulator to be a beta.

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 (CSR, NVRAM)
• WE32100 CPU (CPU)
• WE32101 MMU (MMU)
• PD8253 Interval Timer (TIMER)
• AM9517 DMA controller (DMAC)
• SCN2681A Integrated DUART (IU)
• TMS2793 Integrated Floppy Controller (IF)
• uPD7261A Integrated MFM Fixed Disk Controller (ID)

Usage

To boot the 3B2 simulator into firmware mode, simply type:

sim> BOOT CPU

You will be greeted with the message:

FW ERROR 1-01: NVRAM SANITY FAILURE
               DEFAULT VALUES ASSUMED
               IF REPEATED, CHECK THE BATTERY

FW ERROR 1-02: DISK SANITY FAILURE
               EXECUTION HALTED

SYSTEM FAILURE: CONSULT YOUR SYSTEM ADMINISTRATION UTILITIES GUIDE

NVRAM can be saved between boots by attaching it to a file.

sim> ATTACH NVRAM <file>

On subsequent boots, you will instead see the message

SELF-CHECK


FW ERROR 1-02: DISK SANITY FAILURE
               EXECUTION HALTED

SYSTEM FAILURE: CONSULT YOUR SYSTEM ADMINISTRATION UTILITIES GUIDE

Once you see the SYSTEM FAILURE message, this is actually an invisible prompt. To access firmware mode, type the default 3B2 firmware password mcp, then press Enter or carriage return.

You should then be prompted with:

Enter name of program to execute [  ]:

Here, you may type a question mark (?) and press Enter to see a list of available firmware programs.

Booting UNIX SVR3

UNIX SVR3 for the 3B2 partially boots. To boot UNIX, attach the first disk image from the 3B2 "Essential Utilities" distribution.

sim> ATTACH IF <disk-image>
sim> BOOT CPU

Once you reach the SYSTEM FAILURE message, type mcp to enter firmware mode. When prompted for the name of a program to boot, enter unix, and confirm the boot device is FD5 by pressing Enter or carriage return.

Enter name of program to execute [  ]: unix
        Possible load devices are:

Option Number    Slot     Name
---------------------------------------
       0          0     FD5

Enter Load Device Option Number [0 (FD5)]:

Installing SVR3

To install SVR3 to the first hard disk, first, attach a new image

sim> ATTACH ID0 <disk-image>

Then, boot the file idtools from the "3B2 Maintenance Utilities - Issue 4.0" floppy diskette.

From idtools, select the formhard option and low-level format integrated disk 0. Parameters are:

               Drive Id: 5
       Number cylinders: 925
      Number tracks/cyl: 9
   Number sectors/track: 18
    Number bytes/sector: 512

After low-level formatting integrated disk 0, boot the file unix from the first diskette of the 3B2 "Essential Utilities" distribution, and follow the prompts.