LSIbox - What you can do with it

Parent Category: Projects Category: LSIbox Written by Administrator

 LSIbox is intended to be a "Swiss-Army-Knife" for QBUS PDP-11 operations.

Here's a list of use cases: 


Simulation & Emulation

LSIbox is a Linux system with 4 real RS232 ports. This allows for many simulation setups.

Emulate pure virtual systems (not just PDP-11s) by running SimH under Debian.

Operate a SimH setup with a physical terminal connected to one RS232.

Operate Debian over a physical terminal.

Open "Minicom" (or other) terminal emulations on the Debian desktop, and connect them to BeagleBone UARTs. This way LSIbox replaces up to 4 physical RS232 terminals.

Activate the internal null-modem connection and operate the PDP-11 console over terminal emulation.

Do all this not on a Debian desktop, but on ssh connection. Then the only cables to LSIbox are power line and Ethernet.


BeagleBone development

LSIBox is also a case for the BeagleBone Black, and one of the UARTs is the serial system console with UBOOT access.

Many GPIOs are available over the BlinkenCape plug.

The right most LED on the PDP-11 switch panel is under GPIO control.

This helps while using BeagleBone for development or just adapting the lastest operationg system for it.


PDP-11 operation

LSIbox is a miniaturized BA23 case. You can do everything as on a physical PDP-11.

A special control software "lsictrl" was written. Among other things it can operate the panel switches HALT and RESTART, so no physical contact to LSIbox is necessary.

Connect tools like PDP11GUI to the PDP-11 SLUs.

Connect physical VT100 terminals to the PDP-11 SLUs. 

The SCSI2ID card can emulate 8 MSCP drives on a QBUS SCSI controller. So you can install many different operating systems, but they all have to boot from the MSCP-SCSI-controller.

Of course you can always add other QBUS cards with external disk or tape drives, or printers, or other communication equipment.

IF a DEQNA network card is installed, connect the PDP-11 over AUI converter and a 10MBit switch to your LAN. DECnet is possible, 2.11 BSD can do TCP/IP.
With a DEQNA card you can build DECnet network between the LSI11 and BBB-SimH machines. Or with other PDP's.

Debian can run services, which connect RS232 UARTs to telnet ports. Switch two LSI SLUs to BBB UARTs, and you can operate the LSI-11 over telnet directly. LSIbox acts a bit like a terminal concentrator then (see DECserver).

When BBB and PDP-11 are connected over internal null-modem, you can transfer files between both with the Kermit protocoll. All installed DEC operating systems have one, under Debian "ckermit" is used.

Since the LSI SLUs can be connected to BBB UARTs, Linux programs have full control over PDP-11 comsole input/output.
For example: build a AI program which can play ADVENTURE ;-)


PDP-11 program development

Develop installation procedures for new DEC operating systems first on SimH, then try on the real machine on an unused SCSI2ID partition.

Even under pure Linux you can translate MACRO-11 programs with a cross-assembler, and load and run the resuting listings files with "lsictrl".
Encode Breakpoints with "HALT" opcodes, read memory and registers over ODT. Extensions to "lsictrl" can sniff for halted machine (it reads the RUN CPU signal), then automatically make register dumps over ODT commands.

Or run PDP11GUI on a Windows-PC, connect to the PDP-11 SLUs, and have a more comfortable environment.

If the LSI SLUs are connected to BBB UARTs internally, the UART resp. SLU output still appears on the external ports.
This makes serial protocoll analysis easy: the T-style adapters to intercept serial traffic in both directions are already there.


Running PDP-11 standalone code

You don't need an operating system to run code on the PDP-11.

"lsictrl" can load and start every MACRO-11 listing and every Papertape image over ODT console connection.

Papertapes include a BASIC, a multi-tape FORTRAN compiler,editors and many XXDP standalone diagnostics (extension *.BIN or *.BIC). 

Running XXDP and RT-11 with shared files: tu58fs

TU58 ist a tape with 256kB cartridges, and a serial RS232 interface.

"tu58fs" is a serial TU58 emulator, which save the "tape" content not as binary image, but as file set in a Linux directory.
tu58fs understands XXDP and RT-11 filesystems, and can run oversized "tapes" not limited to the 256KB TU58 cartridge size.
And it can download a TU58 bootloader and start it.

So you can boot full XXDP and RT-11 installations just over internal null-modem connections. Only minimal PDP-11 hardware is needed: CPU, RAM, and a 2 channel serial card.

And the shared "TU 58 tape" directories on BeagleBone can be accessed from anywhere over TCP/IP.


Hardware diagnostics and repair

When you try to fix your QBUS PDP-11:

QBUS cards in the LSI card cage are easy to access for repair work or logic analyzer probes. The first QBUS card in card cage can even be accessed without extender. Also the wire wrap H9270 backplane pins are at your finger tips.

You can run diagnostics in papertape format by direct loading over ODT with lsictrl.

You can run XXDP diagnostics over tu58fs simulations.

You can develop own MACRO-11 assembler programs, download and run them.

Or use PDP11GUI.