9d849283a4
- This change introduces a full refactor of the interrupt subsystem
for the system board (SBD) and the I/O bus (CIO). Interrupt decode
should now be significantly faster, and not require an expensive
calculation on every step.
- The TIMER device has been split into Rev 2 and Rev 3
implementations.
- The optional 3B2/400 Debug Monitor ROMs can now be booted by passing
the "DEMON" argument to the 3B2/400 simulator BOOT command. Any
of the following will cause the Debug Monitor ROM to be booted
instead of the standard 3B2/400 ROM:
sim> BOOT DEMON
sim> BOOT CPU DEMON
sim> BOOT DEMON CPU
129 lines
3.8 KiB
Markdown
129 lines
3.8 KiB
Markdown
AT&T 3B2 Simulator
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==================
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This module contains the source for two simulators:
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1. A simulator for the AT&T 3B2 Model 400 computer (Rev. 2)
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2. A simulator for the AT&T 3B2 Model 600 computer (Rev. 3)
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The 3B2/400 simulator is complete, usable, and robust. The 3B2/600 simulator
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is not yet usable, however. It is under active development.
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Full documentation for the 3B2 simulator is available here:
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- https://loomcom.com/3b2/emulator.html
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Devices
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-------
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The following devices are simulated. The SIMH names for the simulated
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devices are given in parentheses:
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- 3B2 Model 400 System Board with 1MB, 2MB, or 4MB RAM (CSR, NVRAM)
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- WE32100 CPU (CPU)
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- WE32101 MMU (MMU)
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- PD8253 Interval Timer (TIMER)
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- AM9517 DMA controller (DMAC)
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- SCN2681A Integrated DUART (IU)
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- TMS2793 Integrated Floppy Controller (IFLOPPY)
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- uPD7261A Integrated MFM Fixed Disk Controller (IDISK)
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- Non-Volatile Memory (NVRAM)
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- MM58174A Time Of Day Clock (TOD)
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- CM195A Ethernet Network Interface (NI)
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- CM195B 4-port Serial MUX (PORTS)
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- CM195H Cartridge Tape Controller (CTC)
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Usage
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-----
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To boot the 3B2 simulator into firmware mode, simply type:
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sim> BOOT
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You will be greeted with the message:
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FW ERROR 1-01: NVRAM SANITY FAILURE
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DEFAULT VALUES ASSUMED
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IF REPEATED, CHECK THE BATTERY
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FW ERROR 1-02: DISK SANITY FAILURE
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EXECUTION HALTED
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SYSTEM FAILURE: CONSULT YOUR SYSTEM ADMINISTRATION UTILITIES GUIDE
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NVRAM and Time of Day can be saved between boots by attaching both
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devices to files.
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sim> ATTACH NVRAM <nvram-file>
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sim> ATTACH TOD <tod-file>
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If you have no operating system installed on the hard drive, on
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subsequent boots you will instead see the message
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SELF-CHECK
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FW ERROR 1-02: DISK SANITY FAILURE
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EXECUTION HALTED
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SYSTEM FAILURE: CONSULT YOUR SYSTEM ADMINISTRATION UTILITIES GUIDE
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Once you see the `SYSTEM FAILURE` message, this is actually an
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invisible prompt. To access firmware mode, type the default 3B2
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firmware password `mcp`, then press Enter or carriage return.
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You should then be prompted with:
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Enter name of program to execute [ ]:
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Here, you may type a question mark (?) and press Enter to see a list
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of available firmware programs.
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Booting UNIX SVR3
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-----------------
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UNIX SVR3 is the only operating system available for the 3B2. To boot
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UNIX, attach the first disk image from the 3B2 "Essential Utilities"
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distribution.
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sim> ATTACH IFLOPPY <floppy-image>
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sim> BOOT
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Once you reach the `SYSTEM FAILURE` message, type `mcp` to enter
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firmware mode. When prompted for the name of a program to boot, enter
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`unix`, and confirm the boot device is `FD5` by pressing Enter or
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carriage return.
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Enter name of program to execute [ ]: unix
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Possible load devices are:
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Option Number Slot Name
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---------------------------------------
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0 0 FD5
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Enter Load Device Option Number [0 (FD5)]:
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Installing SVR3
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---------------
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To install SVR3 to the first hard disk, first, attach a new image
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to the IDISK0 device:
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sim> ATTACH IDISK0 <hd-image>
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Then, boot the file `idtools` from the "3B2 Maintenance Utilities -
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Issue 4.0" floppy diskette.
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From `idtools`, select the `formhard` option and low-level format
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integrated disk 0. Parameters for the default 72MB hard disk are:
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Drive Id: 5
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Number cylinders: 925
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Number tracks/cyl: 9
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Number sectors/track: 18
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Number bytes/sector: 512
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After low-level formatting integrated disk 0, boot the file `unix`
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from the first diskette of the 3B2 "Essential Utilities" distribution,
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and follow the prompts.
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