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Corvus disk drive for LSI-11

shirsch

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I have a Corvus "flat-cable" drive and quad-height QBus interface and am trying to bring it up under RT-11 on a 16-bit Heath H-11. Currently using a QBone to provide console, memory and MSCP storage (system is booted from that). I can find almost no information on use of a Corvus with LSI-11 systems beyond the fact that it appears as an RL01 at the system level. I know the controller and drive are talking and I see some activity when trying to 'INITIALIZE/BADBLOCKS DL0:'. But, it throws an immediate error complaining about bad directory blocks. There are definitely not any bad blocks, since the drive uses a Gesswein MFM emulator and passes all diagnostics when connected to an Apple 2 system.

I think there was a prep utility that setup basic disk layout, but since no documentation has turned up that's just a guess. Would appreciate input or suggestions on how to get this going. Someone, somwhere must have seen or worked with the Corvus in this environment and I thought this was a good place to start asking.
 
From the lack of response, I'm starting to believe that Corvus must have sold about 5 of these - if that many. I'm in touch with a bunch of folks in the PDP-11 community and to this point no one can recall ever laying eyes on the Corvus system. Bummer.
 
I remember seeing some of these used with AppleII systems and I did own one BITD,but never actually figured out how to use it.
So, yes, you have some *very* edge-case hardware there. You might have more luck in the technical support/hardware section in case someone had one attached to a non-dec system and remembers anything about it.
 
I have a small mountain of Corvus hardware, docs and software pertaining to just about every type of early 80s system, so general knowledge of the device is covered. To my dismay, there seems to be absolutely nothing out there on Corvus drive interface to PDP-11 QBus systems. There was a "flat-cable" interface (the one I have) and a later dual-height Omninet adapter which I'd love to get ahold of but have never found.
 
I have a Corvus "flat-cable" drive and quad-height QBus interface and am trying to bring it up under RT-11 on a 16-bit Heath H-11. Currently using a QBone to provide console, memory and MSCP storage (system is booted from that). I can find almost no information on use of a Corvus with LSI-11 systems beyond the fact that it appears as an RL01 at the system level. I know the controller and drive are talking and I see some activity when trying to 'INITIALIZE/BADBLOCKS DL0:'. But, it throws an immediate error complaining about bad directory blocks. There are definitely not any bad blocks, since the drive uses a Gesswein MFM emulator and passes all diagnostics when connected to an Apple 2 system.

I think there was a prep utility that setup basic disk layout, but since no documentation has turned up that's just a guess. Would appreciate input or suggestions on how to get this going. Someone, somwhere must have seen or worked with the Corvus in this environment and I thought this was a good place to start asking.

I have only seen these in the wild a few times and they were not under my administration.

I would suggest you try the following to see if it possible to tease out some information that would you narrow down the a path to take. You may have already done many of these things. If you would share some photo's of the device's that would help as well.

Is your interface the same as recently posed in http://bitsavers.org/pdf/corvus/flat_cable_interfaces/Corvus_QBus_IF/QBus_Interface_bd_b.jpg ?
Triple check the cable alignment and connector pins between the devices.
Have you tried DL1:, DL2… etc
Do you get the same error messages when the cables are disconnected?
Try a DUMP/TERM/IGNORE/ST:n/End:n+1 DLm: at various spots and see if there are different responses
run LOAD DL and then share the results of SHOW DEV. Let see what the driver settings are.

Good luck - Jerry
 
My interface is the one shown on Bitsavers. Al asked for photos last week since he had never seen nor heard of the board.

I have checked all cables and connections.

I only get a response on DL0:, which makes sense since it emulates a single RL01.

Your point about trying with the drive disconnected is well taken and I will try it. UPDATE: With the drive disconnected it crashes into the monitor when I attempt to access it.

I'm not familiar with the DUMP/TERM, etc. command you mention. If it's documented in the RT-11 manual I'll read up on it.

And, I'll get the results from the LOAD DL and SHOW DEV commands.
UPDATE: It shows

Dev Status CSR Vector
DL 114060 174400 160


Thanks for your response!
 
Last edited:
@wa2flq I posted a response above. The DUMP/TERM/... command simply displays the same garbage (whatever happens to be in the buffer area) regardless of block position.

I'm guessing that '114060' status means something went wrong during driver initialization. Would appreciate your take on that if you have a moment.
 
@wa2flq I posted a response above. The DUMP/TERM/... command simply displays the same garbage (whatever happens to be in the buffer area) regardless of block position.

I'm guessing that '114060' status means something went wrong during driver initialization. Would appreciate your take on that if you have a moment.
My interface is the one shown on Bitsavers. Al asked for photos last week since he had never seen nor heard of the board.

I have checked all cables and connections.

I only get a response on DL0:, which makes sense since it emulates a single RL01.

Your point about trying with the drive disconnected is well taken and I will try it. UPDATE: With the drive disconnected it crashes into the monitor when I attempt to access it.

I'm not familiar with the DUMP/TERM, etc. command you mention. If it's documented in the RT-11 manual I'll read up on it.

And, I'll get the results from the LOAD DL and SHOW DEV commands.
UPDATE: It shows

Dev Status CSR Vector
DL 114060 174400 160


Thanks for your response!

I figured that the appearance on Bitsavers was not a coincidence.. ;)

The status actually reports information about the handler that is loaded and what features/fuctions are available to programs. The details how to decode in AA-PE7VA-TC_RT-11_Device_Handlers_Manual_Aug91.pdf. There is also a copy of a typical DL handler in there. There is no/little interaction with the drives when most handlers are loaded. OS and handler features can vary, so it always good to check.

I suspect most of the "brains" here are not on the board itself. It simply serves to facilitate the appearance of device registers, DMA, etc… Absent a working connection to the drive, the board probably doesn't even have the ability to represent device CSR's. Hence the monitor crash when disconnected from the drive.

If you are able to boot a XXDP+ disk image with the QBone there are several RL controller and drive diagnositic programs to run ( ZRLGEO, ZRLHB1, etc ). This may give you more information. It is typical that emulated drives don't always perfectly emulate a DEC device, so you might get a few spurious errors even on a fully working device.
 
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