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What to do with minimal LSI-11/03 system?

J

jmdhuse

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Hello All,

I bought an M7264 etch rev E board (KD11-AB?) that was pretty cheap as it was identified as non-functional. I discovered that there was a bad DRAM in the onboard memory, so I carefully replaced it and now it can operate properly from the on-board memory. I'm wondering what can be done with just the 4KW that it has... It is too small to boot the XXDPSM monitor (which requires a minimum of 16KW).

Did DEC (or anyone else for that matter) produce some simple system that would run on the stand-alone CPU?

By the way, here's an interesting item about this board. The id etched on the back side of the board is "5055545E-P2", while other etch rev F and H boards have the id "5011545" (the central "55" replaced with "11"). It seems strange that DEC would change the board ID when switching from the rev E version. I've not come across other DEC modules that have such an inconsistency across revisions.

Anyway, just curious what can be done with this minimal system - I have memory modules (M8044) so that I can expand to it's maximum, but what's the fun/challenge in that?

Thanks, Jon.
 
4kW seems to put the system in the realm of paper tape BASIC and maybe other paper tape options. Unfortunately, the Bitsavers version of the LSI-11 User Manual is missing two of the pages on operating a minimal PDP-11/03 with paper tape.
 
krebizfan said:
4kW seems to put the system in the realm of paper tape BASIC and maybe other paper tape options. Unfortunately, the Bitsavers version of the LSI-11 User Manual is missing two of the pages on operating a minimal PDP-11/03 with paper tape.
Click to expand...
Ah yes! I completely forgot about paper tape systems... My first experience with a computer was learning to program on an HP2116C that had an ASR33 and a high-speed paper tape reader - I taught myself ALGOL on that machine. I will explore this - thanks!
 
The problem with the User Manual is that there are a couple of key pages missing.

Obviously, the CPU card doesn't contain any serial ports, so you will have to add (for example) a DLV card. This will be required if you need to interact with ODT.

The other issue is that you may need a ROM bootstrap card if ODT can't bootstrap your device.

I see there is a <CSR>L command for possibly loading from a paper tape device. I have not come across this command before. Perhaps it is unique to this card, or I just have not read of this before.

A TU58 boot will almost certainly require an external ROM card.

Dave
 
daver2 said:
The problem with the User Manual is that there are a couple of key pages missing.

Obviously, the CPU card doesn't contain any serial ports, so you will have to add (for example) a DLV card. This will be required if you need to interact with ODT.

The other issue is that you may need a ROM bootstrap card if ODT can't bootstrap your device.

I see there is a <CSR>L command for possibly loading from a paper tape device. I have not come across this command before. Perhaps it is unique to this card, or I just have not read of this before.

A TU58 boot will almost certainly require an external ROM card.

Dave
Click to expand...
I have a boot ROM module I can use, but the TU58 emulator also has a feature to load the TU58 bootstrap via ODT... it just takes a couple of serial ports, which I have on a DLV11-J. So that's the minimal system - the CPU with 4KW of on-board memory and the serial port module.
 
jmdhuse said:
Hello All,

I bought an M7264 etch rev E board (KD11-AB?) that was pretty cheap as it was identified as non-functional. I discovered that there was a bad DRAM in the onboard memory, so I carefully replaced it and now it can operate properly from the on-board memory. I'm wondering what can be done with just the 4KW that it has... It is too small to boot the XXDPSM monitor (which requires a minimum of 16KW).

Did DEC (or anyone else for that matter) produce some simple system that would run on the stand-alone CPU?

By the way, here's an interesting item about this board. The id etched on the back side of the board is "5055545E-P2", while other etch rev F and H boards have the id "5011545" (the central "55" replaced with "11"). It seems strange that DEC would change the board ID when switching from the rev E version. I've not come across other DEC modules that have such an inconsistency across revisions.

Anyway, just curious what can be done with this minimal system - I have memory modules (M8044) so that I can expand to it's maximum, but what's the fun/challenge in that?

Thanks, Jon.
Click to expand...
Years ago I built a stand-alone fig-FORTH system that fits in 4KW with room to spare. I run it on a T-11 wire-wrap board that has 8KB of RAM and 8KB of EEPROM. The only default I/O is a console UART.
At boot time, the T-11 runs from EEPROM, copies its entire 8KB image to RAM, then jumps into RAM.

I have a variation of the same thing that runs on an LSI-11/2 in a dual-height 4-slot backplane with an MXV11 (memory + serial), plus a wire-wrapped I/O card that does some other stuff. There is an EPROM with boot code in the MXV, which expects to receive a code image via a serial port (much like a TU58 boot, I suppose). For "storage", a modern MPU board (MSP430) acts as a boot device to load the FORTH image. Using the MSP430's USB UART 'console', it can talk to my Windows PC, where I have an app that lets me easily update the code image.

Pete
 
Yeah, paper tape was my first thought, you can run Fortran 4K if I recall and compile/link some simple programs.

But if you go to 30kw of memory you can do a lot. My favorite system was my 11/V03 with 28kw memory, RX01 floppies, and it ran MUBASIC on 4 DLV11 terminals. Impressive little timesharing system.
 
Radix said:
Have you looked at this: http://retrocmp.com/tools/pdp11gui

Otherwise, maybe go a bit less minimal and add a cheap 64KB Ram card and you can run RT11, booting from TU58FS.. It's not fast - but it works...
Click to expand...
Yes, I have started investigating PDP11GUI...

Also, I have configured the system with full memory and have booted both XXDP and RT11 via the TU58 emulator - I have been playing Adventure on this configuration - I was just taking up the challenge of finding something interesting to do with the minimal system...
 
Quick update - I now have Basic running on the system with only the 4KW resident memory (using PDP11GUI go load the paper tape image). I know it's not a huge accomplishment, but it confirms that my repair work was effective (the module was non-functional when I bought it). I'm smilling...
 
Just out of interest, do you have a paper tape reader unit?

If you do, you should be able to make a paper tape leader to act as a 'fast typist' using ODT commands to load the serial bootstrap and to then bootstrap the BASIC interpreter - or whatever software.

Obviously, this is doing what PDP11GUI is largely doing - but doesn't require an additional peripheral (the PC) that has many times the computing power of the PDP-11...

Dave
 
daver2 said:
Just out of interest, do you have a paper tape reader unit?

If you do, you should be able to make a paper tape leader to act as a 'fast typist' using ODT commands to load the serial bootstrap and to then bootstrap the BASIC interpreter - or whatever software.

Obviously, this is doing what PDP11GUI is largely doing - but doesn't require an additional peripheral (the PC) that has many times the computing power of the PDP-11...

Dave
Click to expand...
I'm working on building a paper tape reader, but at this point I don't have any paper tapes (and I don't know where to source them) - I'd like to get my hands on actual paper tapes of the absolute loader and the Basic interpreter.

I've looked at purchasing a reader/punch, but they are too pricey for my hobby budget...
 
Yes, these things are quite expensive nowadays.

We threw away loads of ASR-33 and KSR-33 teletypes back in the day (from work). I am really sad about that now I know better!

If you go to a VCF event, you may be able to persuade someone to punch out what you want - for a suitable fee.

Dave
 
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