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PDP-11/23 automatic boot ?

smp

smp

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Oct 4, 2011
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Location
Bedford, NH, USA
As folks here already know from my postings, I have a PDP-11/23 with the following boards installed:

Row 1 = M8186
Row 2 = M8044 DB
Row 3 = M8044 DB
Row 4 = M7940 (console)
Row 5 = M7940 (address 17650x)
Row 6 = Emulex UC07 (SCSI Interface)
Row 7 = M7946
Row 8 = empty
Row 9 = M8012 YA

I am successfully running RT-11SJ at present. I have to manually type in a short boot program in ODT for my Emulex SCSI interface, and then the system is able to boot into RT-11.

I would like to be able to have my system automatically boot up from my SCSI drive. When I power up my system, it signs on with:

28
START?

I then answer with N, and it prints out the available memory and drops into ODT:

I have tried answering with Y, but the system does not indicate anything obvious. I have also tried answering with DU or DD, but, again, nothing obvious. I forget if the system ever comes back to ODT, or if I simply gave up after 20 seconds and did a restart.

What are the possibilities for me to get my system to be able to boot up automatically, or can I get it to the point that I can type in an answer to the START? question and get it to go from there? I am suspecting that I should start by examining the M8012 board, right? What should I discover there?

Thanks, in advance, for your patience with me.

smp
 
The 23-045E2 / 23-046E2 ROMs you have on your M8012 BDV11 do not support booting from MSCP devices.

If you have newer ROMs on an M8189 KDF11-B 11/23-PLUS they do support booting from MSCP devices. I replaced the 2KB EPROMs on my M8189 KDF11-B 11/23-PLUS with 8KB EPROMs (24-pin MC68766) version 23-380E4 / 23-381E4 firmware to get MSCP boot support.

I don't know if you can manage to somehow load the version 23-380E4 / 23-381E4 firmware on an M8012 BDV11. The M8012 BDV11 manual only mentions 1KB and 2KB ROMs / EPROMs.
 
Remind me... what firmware are you running on the BDV? It doesn't look like you have Lou's modification. There's a thread or an article Lou posted here someplace.

I see Gslick already posted... Lou's mod involves what he's talking about, but on the BDV.


The only alternative I can think of is to check if your SCSI card has a boot. If it does, follow the instructions for that. It might involve removing the BDV.
 
Thanks very much, guys!

I'm at work today (my employer does not grant President's Day as one of our holidays).

I printed out the reference thread (thanks Glen!) and I'll look it over. I'm sure that I'll have more questions.

smp
 
Do you have an EPROM programmer and spare EPROMs to give this a try yourself?

I think I only have a few 2716 EPROMs but I do have several spare 2532 EPROMs that I could use in place of 2716 EPROMs on a BDV11. It looks like the 2352 extra address line A11 on Pin 18 is connected to ground on the BDV11 so I could just program the 2716 2KB images into the low half of the 2532s.

-Glen
 
gslick said:
Do you have an EPROM programmer and spare EPROMs to give this a try yourself?
Click to expand...

Hi Glen,

No, and no.

I figured that this would not be a quick thing for me. I'll have to order up some 2716s from DigiKey or JameCo. I'll also have to study all the things that are in that thread. I have the Microcomputer Interfaces Handbook, at least, so now I can study up on the BDV11. I want to fully understand all the jumpers and switch settings prior to going off and doing anything.

Thanks again for all the attention.

smp
 
Well you won't be buying 2716 parts from Mouser or DigiKey, they have been obsolete for years. You can buy 10 of them shipped from Hong Kong or China on eBay for about $15-20. It's crazy, I bought some 27C1024 parts from Hong Kong recently and they arrived the same week.
 
Here is just one example on eBay today, 10pcs M2716-1F1 for $15.63 including shipping from Hong Kong.

http://www.ebay.com/itm/181184916823

I have no experience with that particular vendor. I bought the M27C1024 parts from a different Hong Kong vendor on 2/9/2014 and they arrived on 2/13/2014. Two of the ten parts where were not completely blank and I had to stick them in the UV eraser. Haven't actually tried to program and verify any of them yet. There is always some risk of getting questionable parts when dealing with eBay.

M2716-1F1 == 350ns, 5V +/-10%
M2716-F1 == 450ns, 5V +/-5%
 
I wouldn't go crazy buying 2Kx8 proms... look for 4Kx8 instead. (2732s)
 
I agree, I did this mod with 2732's, and burned the image twice, meaning I took each 2k image, joined it to itself and made a 4k image. IIRC, copy/b image.bin+image.bin dblimag.bin was the command in DOS (yes, this can be done in unix/Linux too).

2732's are more common than 2716's these days and have the same pin out.
 
SMP,

This is an easy mod. If I (a mechanical engineer) can figure it out, you'll have no trouble. Since Crawford did this with 2732s, perhaps he can post the jumper settings and IC locations for that version.

It kills me to hear people pay money for these eproms. In the good old days, at the end of a hamfest when piles of boards would be left behind for trash, our crew would scavenge whatever we wanted. If it was in a socket, it got scavenged. I think I only have a dozen 2716/2516s left though, but pounds of 2764s!!

Lou
 
Hi All;
I have a pile of 2732's that If you need some I am sure something could be worked out..
Since in my Old Computers, I mostly use 1702's, 2708's and 2716's..
In my last project I had Run out of 2716's and had to get more.. But, I have enough now..
THANK YOU Marty
 
Lou - N2MIY said:
Since Crawford did this with 2732s, perhaps he can post the jumper settings and IC locations for that version.
Click to expand...


Since Crawford burned each 2K image twice into each 2732, he still ended up with the equivalent of a 2716, so I don't think that the jumper and switch settings would be any different.

Crawford: What was the reason for doing this?

Right now looking at eBay, I see that 2716s and 2732s are both selling for $3.50 - $4.00 each. Since a true 2732 solution would use half the number of devices (4 instead of 8 ) it would be a half price solution. That would be attractive. But, I don't think that anyone has actually done it yet.

smp
 
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In the vast majority of circuits designed for 2716, a 2732 may be substituted by burning the intended program to the upper half of the device. Burning to both halves should be pretty universal.

I always intended to see if I could rework a BDV to accept 4Kx8 devices (4 total) but never got a round tuit. ;)
 
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Ok, I understand now. I should have read more closely. Yes, the jumper settings and IC locations should all be the same.

So then, eight 2732s would do the trick. $4 each. Wow. That's almost half the cost of an eprom programmer!

You should ask around at work if there are any electronics hobbyists who have some in their cellar that they'd give you.

Lou
 
Well you could always go all the way and hack up something to use only two 8KB MC68766 parts, but if your time is money you would probably waste a lot of time wiring up and mapping 4 separate chip selects into 2 extra address lines and duplicating that twice and come out way behind in the end. I suppose you might get some entertainment value and satisfaction out of doing it though.
 
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