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PDP-11/RX02 Boot Bules

Q

Qbus

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I have a PDP-11/23 system that has been abusing me for some time now. I would like to get the system to boot RT-11 from a RX02 drive but am a little short on media and experience. I do have a couple disks, one that’s format and a second that’s formatted with RT-11 but it was built on a Heathkit H-11 This system has the BDV-11 bootstrap / terminator and I can call for it to load from the RX02 from the con but when I use the disk that has the operating system on it the system starts loading the disk and all contact to or from the terminal goes away. The run light stays on like the system doing something but no way can I do anything from the terminal or printer port. Have to hit reset to knock the system back into the loader program or ODT. Maybe the H-11 has different port addresses then the PDP-11 and its looking for input somewhere else? Is there anyone out there that has RT-11 or any other operating system on an eight inch disk I can talk out of? I also have a RL-01 on the system with a disk I played a whole lot of money for with RT-11 and utilities but my RL-01 is a unit I put together from two dead drives and don’t think I have the head alignment right on that yet so not a lot of love from that drive.
Ray F.
 
I'm not familiar with the H-11, but I may be able to help you if you can direct me to somewhere I can get a concise understanding of it.

It sounds like the disk you've got is indeed bootable. You might be losing the chain of BOOT events for several reasons I can think of, but it all comes down to some critical difference between the 11/23 system you have and the one the disk expects.

Things I can think of off the top of my head...
  • Console Serial device different or at a different address
  • Unexpected hardware device being booted
  • missing memory or cpu attributes
  • bad 11/23 configuration [I.E. Waiting on a device that is on the bus but beyond a gap in the bus grant chain [needs a bus grant card installed or re-arranged cards] ]
This last item can be eliminated if the 11/23 can be used with all devices on another OS. Has it worked before in this config?

You could try sending the console a BREAK once it enters the dormant condition to see if it responds. If it does, it will return to ODT with an address. Looking in memory at that address might give you a clue what it's waiting for.

Hope some of that helps.
 
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Does the H11 use standard MFM or "DEC" MFM (i.e. RX02 type) to do its recording? If you can read the H11 disk using, say, normal PC hardware using a utility like AnaDisk (or your favorite *nix utility), it isn't DEC RX02 MFM (single-density address headers with double-density data fields with some alterations in the bit patterns so as not to confuse FM gear).

RX01 FM recording is the same for both platforms.
 
Chuck,

The H27 floppy drive for the H11 computer emulated an RX01. So, yes, a normal PC with a properly fitted SA8XX style drive can read RX01 media. I do this with an SA860 connected to an IBM PC300 running PUTR.

Ray,

Where in the world are you? I can mail you a known bootable RT11 RX01 to try. Of course, it would expect the stock CSR/vector for your RXV11 controller (177170 / 264) as well as the stock CSR (177560 / 60) for the console.

Did you loosen the setscrew that allows the head positioning motor to be rotated or did you mess with the track zero flag or photogate? That can screw things up royally. In general, I have not usually had to do a head realignment on RX01s or 2s, but I have done it twice. They seem to be pretty solid (stable) drives.

When you tell the BDV11 to boot from DX, do you hear the head load solenoid in the RX01 make a loud kerchunk? Have you done the other PM on the RX01 also, like check the belts and clean the heads? Also check the felt button on the upper spring loaded head load arm to make sure that it is there and pushing on the non data side of the disk.

If you have DLV11-J as the SLU card, you can try to boot the system from an emulated TU58 (running on a PC). Your BDV11 may have the DD bootstrap in rom depending on the rom level. See if it chokes if you tell it to boot from DD.

Lou
 
Lou - I think the idea of sending him a "known good" system disk will really eliminate many potential issues. :thumbsup: It will confirm if his 11/23 hardware is setup correctly, or not.

I have some RL01 and RL02 drives to recondition too, so I may be talking to you about these myself at some point.

Got any experience with RK05s? I must have 5 of em. Fortunately, I have no media I need to get anything off of. Still, I'd like to rehabilitate them.
 
Yes, I have done head replacements and aligned RL01 and RL02 drives. I too have some RK05s that need a lot of attention, as well as an RK8E to be repaired. I intend to start working on that in the spring. My only RK05 experience so far has been a lot of reading and looking at the hardware. I have not dug in yet... But yes, the RK05 packs seem to be scarce...

Lou
 
Lou said:
RK05 packs seem to be scarce...
Click to expand...
Talk to me when you get to that point... I may have a few spares for you.

I'd be interested in equipment swaps for the drives too.

How long since you've seen an RM03?
 
Pdp-11/rx-02

Pdp-11/rx-02

Great responses, thanks to everyone. Hopefully I can attempt to answer a couple questions. First the system I have is a built is from parts I have collected. I have a 11/03 frame and expansion case that was updated to a 11/23 using a KDF-11 card in slot one, the next three to four slots are 32k memory cards depending on if I am using one for the other 11/23 I have on the work bench. Next is the 8029 interface for the RX02 and the two RLV11 cards for the RL01 drive and at the bottom of the frame a 9404 jumper extending to the expansion frame and connecting to slot 1, a DLV quad serial card, not a DEC one but some aftermarket card and last but not least a BDV-11 stuck in the bottom slot. The frames, power supplies and all that stuff check according to the manuals although not cretin about those stupid "W" jumpers on the control but think I have them set correctly because the reset and halt functions work, the jumpers on the frames are what they are supposed to be for master frame and expansion chassis, and as far as the order of the cards I have no idea. Everything I read says something different about stacking the cards and I am open to any suggestions. The system will run diagnostic that I type in on the con and the loaders on the BDV all work. If I tell the system to boot from the RX and the drives empty or the doors open it comes right back with the drive not ready error or if I send it to the RL and its not in a ready state I get the drive not ready error again so the loader is functioning and am fairly confident on communications with the drives but now for the bad news, when I purchased the RX and two RL drives they were in very bad shape. They had been in storage for maybe ten to twenty years and were extremely dirty. I had to completely disassemble the entire units to clean them, the AC disk drive motors were seized and I needed to disassemble them to free the frozen bearings. I did not disassemble the disk head assemblies but did remove the mechanism and cleaned and lubricated them. When I tell the system to boot from RX drive zero the heads do engage but I do not know if the stepper ever moves beyond the first track. Wonder if there is a command I can send from the con that will cause the steeper to move? Or a register that will give any information on what's going on with the drive? I have a program that I can enter thru the con that will tell me the status of the RL register and wonder if I change the address on that if I can see the RX status? Although have not had much success reading registers yet, why do the books always show the registers as being 16 bit words but when I convert the octal results I get back to binary I get a fourteen bit word? And is the binary word read right to left or left to right? Perhaps my brain just not big enough to deal with the 11? There is a web page of all my idiocy at WWW.KA3EKH.NET follow the PDP-11 link and you can see what damage I have done so far, although since then I have located the proper cables for the RL-01 and restacked everything in a smaller rack.
Ray F.
 
Great. While I'm studying your photos... would you please post an additional one, a closer view of the two BA11s with cards and slots visible. If you have a camera with zoom, step back as far as practical and zoom in to fill the view. That will give me a better perspective on the current setup. Your description is great.

Yes... there is a good way to see if the DL is listening to commands and acting on them. I'll look for it, but you need the boot code for the DL. It's like 4 instructions long. You put them in memory. Load a disk and see the ready. Then execute the code. You'll see the drive ready flash if it's working. The final step in the boot is to enter a start address and G if I remember. I've used it as a diag many times.

I need to dig out the 03 backplane docs, so bear with me. If they are the same as the BA23, you'll need to re-arrange some cards. I'll get back asap. Maybe someone else here will know off the top of their head in the meantime.

One suggestion though... when so much is in question, I often found it easier to reduce the system to the simplest configuration possible and troubleshoot it. Once it works, add options one at a time until it all goes. Much easier that way, but I see you're real brave and handy, so feel free to ignore me on this.

I'll be back in a while.
 
Lou... is this you??

Ray - I need to ask if you have verified this is an ABCD backplane 9-slot? BA11-N [H9273-A] [both boxes?] If you haven't, we should do this before going further.
 
Ray,

That's a nice looking system there Ray! I checked it out on your web page.

The 11/03 backplane in your pictures should be an H9273, AKA BA11-N but do check for sure. The Q-bus in these should run down the left slots (AB slots) while the CD slots should only be occupied by the quad height cards. The Qbus is carried only on the AB slots. The CD slots are ONLY used for connecting the two RLV11 boards together in this backplane. So, from your pictures, you got that right. The W2 and W3 should be open in the expansion backplane if I remember right.

Everything else looks really good. You're really close here.

The RXV21 controller is for the RX02. It may not be happy with being connected to an RX01. The "right" controller is an RXV11. (as an aside however, an RX02 does work with an RXV11 when the S1/S2 switches are set properly in the RX02 - I've done it with a unibus RX11) So, this might be part of your problem.

The CSR for RXV21 is 777170 in your Q18 11/23 setup. You don't need to write programs to examine and deposit into memory or the I/O space at the top of memory. You can get to ODT by halting your processor. In ODT you get the @ sign prompt. If you see @ then type 777170/ it will display the contents of the RXV11 CSR (control and status register). If you then type six octal digits, then carriage return, your six digits will be deposited into that register. Works the same for memory locations. 777172 is the data buffer register, which has multiple personalities depending on the command that was sent in the CSR. You can read all about this in the dec RX manuals (did you find bitsavers.org yet?)

Oh and yeah this is a 16 bit machine, but memory is arranged in 8 bit bytes. Each byte has an address, but ODT works with the 16 bit words. So really, the CSR is 777170 and 777171, but 777170/ will show you the whole 16 bit word. 16 bits is 6 octal digits, but the 2 most significant bits of the most significan octal digit are not used. So I think you meant that 6 digits is 18 bits, but only 16 are used. For memory addresses however, in your machine, all 18 bits will be used. (An 11/23+ that can address 22 bits of memory space needs 8 octal digits) I guess this use of octal alwalys made sense when your machines were 18, 12, and 36 bits. Of course the 11 had to break the mold.

The RX02 on powerup, will look for an installed disk by looking at track zero. On a boot, it will look at track zero sector zero for the secondary loader. It may not move out farther than that.... But how did you take the head assembly out of the drive? I am afraid you will need an alignment, and for that you will need XXDP...

By now you have probably also read about XXDP, the diagnostic monitor system. There are diagnostics for everything and they are invaluable. Unfortunately, not all of the code listings are available (or some lucky people have fiche sets, which I do not) so when the diagnostic hangs, you still have some homework to do. On the bench system, I run XXDP on an emulated TU58 drive. I make bootable XXDP TU58 images for whatever controller I am repairing. So currently, I have an image with all the RX diagnostics. There is a diagnostic that will allow you to position the head over a specific track, although not directly. It at least needs to find track zero first. You can find track zero with your scope on the head amplifier output (trigger on the sector index pulse) as you load the head by hand and rotate the head motor, then you have to get the track zero sensor aligned right. Basically if you ever aligned the heads on an SA800 you will have an idea of what to do.

A real analog alignment disk is nice, but you might be able to get it to work good enough with a real dec RX01K floppy. Dec RX01Ks were pre-formatted by dec and *should* have reliable track locations. I have done this.

Your RL cable work looks impressive. I have thought about replacing those latched connectors with ribbon cable when I eventually run out of the right cables. Do you have RL packs and does the drive come ready with no faults when you spin one up?

RSX11M+, yes, I am that Lou from alt.sys.pdp11. As for your RM03, I never worked with one, however Lou Sr. (my father) probably did. Since RM03 is a massbus drive, he would have seen them on smaller decsystem 20s. You have an RM11? When you start working on your RK05s I am sure we will be able to help each other out.

Lou - N2MIY
 
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Lou... Yeah... I kinda figured it might be you. I must have seen that kind of repair a dozen times, so don't feel too bad.


I was in the middle of extending my post when you responded, so I've canceled that and done this new one instead. I've digested enough to ask a few questions. I could just write a huge tome [Lou's done some of this now - all good info] on what to do and considerations, but that would take me time to write and might not take you where you want to go.

Ray - I guess I'm not quite as optimistic as Lou about your current state. I've seen these things go wrong in big ways, and I don't know you well enough to rule out the customary worries.

  • Lets begin with a mistake that does DAMAGE. I am absolutely paranoid about this "bus type" detail.

    The two photos depict different module configurations. Going based on your description....

    The usual practice would be to put the disk controllers after the serial console device and memories with the BDV11 last on the bus. All the cards in immediate succession, no gaps [except the BDV11]. [not counting CD slot gaps.]
    If you have a 9 slot ABCD backplane, this practice is ok, but if it's a later combination ABCD and ABAB - you'll damage things because the DLV11 cannot be placed in anything but an ABCD slot.[See the link to Lou's other post]​

    All other considerations are secondary to this one.
  • Another damage concern is power supply loading. I need to do a little research on the config, but I'm concerned that the modules in the main box might be a little close to the power limit if this isn't an original BA11-N. More on this in another post.
  • My next concern is memory configuration.

    Have you been through the process we fondly refer to as "Jumpermainia" setting the memory cards? If not, I doubt they could be set to live properly together.

    I would usually like to begin, as I said, with the minimal hardware set to get things going, then add to a working system. If you haven't done this settings exercise with these, then this is most certainly the way to proceed.​


If all my current assumptions are correct, everything you have is probably 18 bit, with the possible exception of the CPU. Actual module numbers will help me confirm this. Would you post them please? [include the CPU]

There were several variations on the KDF11-A CPU. A photo is needed to narrow it down [both sides please].

Finally - The most important BDV11 Documents can be found here
In particular be sure to get:
  • EK-BDV11-TM-001_Mar78.pdf
  • MP00489_BDV11_Sep77.pdf
These will be immensely helpful in diagnosing using the LEDs on the BDV11.

Having said my piece, I think I'll sit back and see what you choose to do from here.

Lou's point about RX01 / RXV21 compatibility strikes a bell. But if the other details aren't attended to, you won't be able to count on what you see. If he can send you a bootable diskette and we can get that much going with say, one memory card and no RLV11, I'd feel much better.
 
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All this talk of the BDV11 made me think of something... I have successfully upgraded two BDV11s from their stock roms to the Micro-11/23 roms (23-380 and 381). This is useful because it gets you the MSCP bootstrap and the nice interactive menu based boot screen (if you have a VT100 or later). I can gladly help someone if they are ever interested in doing this.

There are indeed a number of versions of M8186. I have personally etch A, C and D. I think A may be Q18 only if I remember right.

Lou
 
Always open to archiving more good code.:bigups:

I can offer a set for the MXV11-B2 [... Y3.0 They're on 2764s] in exchange?
 
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So I looked on an MXV11-B2 that was within reach. It has 23-145 and 146 roms on it. Which roms are the Y3.0 you mention?

The trick to putting the micro-11/23 roms on a BDV11 is segmenting them from 64k to 16k roms. So, where there are only two roms on the M8189 11/23+ processor, there will be eight 2716 (or 2516 for TI) on the BDV11. I have also replaced Motorola 68766 eproms (on M8189) with 2764s. You can see that here: http://www.vintage-computer.com/vcforum/album.php?albumid=49&attachmentid=2719 for amusement value.

Lou
 
Sorry Lou, I seem to have frustrated you.

The PROMs I have are in an original [DEC?] antistatic box with internal pad. The outside of the box says: MXV11-B2 4 sets - and hand written Y3.0. [I always assumed this was a revison indicator - it could even be my handwriting] The "4" was crossed out in antiquity, and a "1" scrawled over it.

Inside the box are two EPROMs with typewritten labels - "MXV11-B2 146E4" and "MXV11-B2 145E4". Then below each is written in my handwriting "2764".

I take this to mean that I pulled the labels off and verified the device type. This was a common practice of mine when I was keeping a master set. [I never used the very LAST of anything- silly me]

I just examined the devices, and they show no signs of ever having been inserted.

I'll spend a few minutes tonight locating my preferred PROM programmer and reading them in. I'll post the images when I do.

Any particular format you'd like?
 
RSX11M+ said:
The PROMs I have are in an original [DEC?] antistatic box with internal pad. The outside of the box says: MXV11-B2 4 sets - and hand written Y3.0. [I always assumed this was a revison indicator - it could even be my handwriting] The "4" was crossed out in antiquity, and a "1" scrawled over it.

Inside the box are two EPROMs with typewritten labels - "MXV11-B2 146E4" and "MXV11-B2 145E4". Then below each is written in my handwriting "2764".
Click to expand...

Those likely match the binaries here:

http://www.dunnington.u-net.com/public/DECROMs/
http://www.dunnington.u-net.com/public/DECROMs/23-145E4.bin
http://www.dunnington.u-net.com/public/DECROMs/23-146E4.bin

http://www.dunnington.u-net.com/public/DECROMs/ROMlist
23-145E4 23-146E4 M7195 8K MXV11-B2 boot ROMs
23-146E4 23-145E4 M7195 8K MXV11-B2 boot ROMs
 
I'll check and report back.

Thanks for that link BTW - I'll see if I might have anything on their "wanted list".
 
gona wear out the slots!

gona wear out the slots!

The fun and games never end! I stacked the cards in just one frame on my 11/03LK chassis so slot 1 is the KDF-11, slot 2 the 8029 drive interface, slots 3 and 4 memory, slot 5 the quad serial interface and the BDV-11 is at the bottom row. All cards except the BDV-11 are in the A and B slots with the BDV using all four slots. When I tell the system to boot (DY0) from a disk that was formatted only on the H-11 I get the following prompt on the con “? BOOT-F-No boot on volume” if I tell the system to boot from a disk that was formatted and with RT11v4 from the H-11 I get knocked back into ODT at address 000142, The following is in the requesters R1/000200, R2/004400, R3/000200, R4/177170, R5/177172, R6/007770 and the stack pointer R7/000142 and just for fun I looked at 1000/012737. I did try stacking the 8186 in slot 1, quad card in 2, 8029 in 3, one 8044DK set with all switches open in 4 and a second 8044DK set with switch one down and the other three up and the BDV-11 last and got the exact same results. Looking at the frame definitely an ABCD and not an ABAB, I have read the stuff about stacking the RAM furthest away from the CPU but before the BDV but is that for real? Also starting to think the H-11 system disk ant going to work on the 11/23
Ray F.
 
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