View Full Version : Getting a LSI-11 Running

September 28th, 2010, 08:00 AM
A while back, I purchased a large Kevex 7000-series something-or-other controller at the surplus auction for $10. It had a Z80, loads of discrete logic, EPROMs and large wire wrap boards. I also discovered a LSI-11 hidden in a bottom section, under a metal front plate. I've got the M7270 board, and a M8044 32K RAM board, as well as some custom-looking board that seems to be for program storage and I/O (it's got fuse PROMs and an ADC).

Of course, I have a QBUS backplane from the same enclosure, but I'm not really sure on what I need to get the ODT function of the LSI-11 board functioning. Do I need a separate serial card for the terminal? Is serial functionality provided by the M7270 board? I've been able to find jumper settings and documentation on both the M7270 and M8044, but nothing really detailing terminal connection.

Lou - N2MIY
September 28th, 2010, 04:08 PM
You have a, 11/03 processor and small memory. To connect the console terminal, you will need a DLV11 SLU (serial line unit) adapter. To have any kind of ODT interaction with the console terminal, you will need a bootstrap board, like a BDV11. Alternately, you could use an MXV11 that has two SLUs, bootstrap, and some memory. Then you will need to think about mass storage...

Do you have any surplace places up there in Capital-land where you can find any other LSI-11 hardware?


September 28th, 2010, 04:37 PM
I don't know of any surplus places here that'd carry anything LSI-11 related...though I haven't searched much either. The Kevex unit these came from was purchased in Virginia, at the VT surplus auction, a while back.

Someone has a DLV11 up for auction on eBay for a (currently) reasonable price...I'll keep an eye on that. There's a MXV11 listed too, but they want $200 -- not anywhere near my price range!

It seems someone else (link: http://www.diane-neisius.de/pdp11/index_E.html ) has a LSI-11 running with ODT using only the 11/03 processor, RAM, and a DLV11 interface. Is this person incorrect/not actually using ODT? It seems there are jumpers on the 11/03 board to allow it to boot directly into ODT (which mine is currently jumpered for).

EDIT: actually, it looks like their setup is exactly what I've got...same 11/03 board, same RAM, same card cage. Only thing I'm missing is the serial interface.

Lou - N2MIY
September 28th, 2010, 05:05 PM
Well, good or bad, I have never used an M7270. I have one that some one had scavenged some parts off of. I have never tried to repair it. Hence my ignorance about on-board ODT. I assumed it needed to be loaded from a bootstrap board.

At any rate, I just went upstairs and grabbed the 1979 microcomputer processor handbook. The book calls it the LSI 11/2 processsor. Indeed it does have ODT on board that is accessed when configured for "power up mode 0". My junk board appears to have the KEV11 option (floating point option) if you need one.

So, indeed all you need is a DLV11. Indeed the DLV11-J is a really good choice with four SLUs. One for your console, one for the emulated TU58 you will connect for mass storage, and a third for a serial printer.


September 28th, 2010, 05:20 PM
Good to hear I won't need a bootstrap board! I put an offer in on one of the DLV11-E boards on eBay that had "Best Offer" enabled (doubt they'll bite). If not, I'll get the DLV11-J. I'll have to extract my card cage from the Kevex device -- it's still in Virginia, because it weighs > 80 pounds, with its linear power supply, HV supply for the radiation counter, and internal lead-acid backup cells!

All of the 40-pin sockets on the M7270 board are populated...I don't know what options are installed yet (the chip markings are a little scuffed up). Incidentally, are Multibus boards almost exactly twice the width of QBUS boards? If so, I think I've got one with 8" and 5.25" floppy controller and MFM hard drive control! No idea if the two structures can be interfaced (it's my understanding QBUS == multiplexed Multibus).

Lou - N2MIY
September 28th, 2010, 05:20 PM
I took a look at the web page link you posted. Diane has done a great bit of pieceing together indeed! I see she has an RXV11 controller. Her emulated RX01 would be faster than an emulated TU58, but then it meant there was more she had to build.

The TU58 was a tape drive (Dectape II) that connected to the comupter through an SLU, so no "special" controller was required. However, it's slow. It is useable though, and you can key in the bootstrap loader into ODT and boot RT-11 from a bootable TU58 tape image running an emulator (I like Will's: http://www.fpns.net/willy/pdp11/tu58-emu.htm) I have done this.


September 28th, 2010, 05:29 PM
I can say I've used the emulated TU58 also. It works, but as Lou says it's slow. I loaded RT-11 onto an 11/34 I had using
that. I also still have the Unibus M7856 that I used. Too bad that won't work for you. I've never done much with Qbus
stuff. Good luck and enjoy.
Tim R

September 30th, 2010, 06:06 PM
Well, I got the DLV11-J for $19...no other bids even though there were nearly 200 views. I should now have everything to get the LSI-11 up and running, except the backplane, which is in Virginia at the moment.