simh and emulator file compatibility.

[Jay Cotton]

Hi:

I have pulled a transition file from an st251 disk.  I converted it to an emulator file

and I can boot from that image.

My question is about compatibility between simh and the mfm emulator file format.

Is there a way to make simh work with the output from mfm 'tools'

tnx

jc

[David Gesswein]

Depends on what controller it was written with. You want to generate
extracted data file with mfm_util.

If disk was generated with something like RQDX3 you might be able to modify
the file as in below but not guaranteed to work. That controller is
remapping what on the drive for error handling and other purposes. Nobody
has taken the time to figure out how to undo its mapping.

http://www.pdp8online.com/mfm/status.shtml

Controllers which either remapping is known or don't do any remapping
would work.

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[Ashlin Inwood]

This is a little off-topic topic, but if you want to move an image to something that can run under simh, you may be able to do a backup over a network.

When I was installing VMS into a mciroVAX II I booted the system from simh and copied the disk over the network to the system.

This obviously requires the right type of software and hardware for this to work.

To view this discussion visit https://groups.google.com/d/msgid/mfm-discuss/Z38HbSKZEglVY/vw%40hugin3.

[cub...@gmail.com]

I had forgotten about the issue of mapping blocks on at least some of the RQDXn controllers.  

OK, since you say you can boot from that image, I’m going to assume that you have some kind of real machine.  If that machine is a PDP 11, you can use PDP11GUI  to make an image of a disk without having to worry about how the RQDXn controller maps physical blocks on the disk to logical order.  If you have trouble finding a copy of PDP11GUI that works, let me know and I can provide one.  I found that the highest speed I could make it run at reliably was 38.4 KBPS.

For a VAX, you can use VTserver.

Or once you have a QBone ( because I saw your earlier question on another forum today,) and that is your goal, you can configure the QBone script to be a secondary MSCP controller and just copy all the blocks across that way.

JRJ

[Jay Cotton]

Yes the QBone is on the way.  

So,  with PDP11GUI, I can make a copy of the st251 disk and that copy will run under simh ?  

I have:

11/53 with 512k

RZDX3 with one hard disk, no floppies  (even if I had a drive, I don't have any media for it)

DEQNA that needs software.

My scheme is to install the NA and DD drivers on the bootable image and then use tu58fs to supply other

code as needed.  

tnx

jc

[cub...@gmail.com]

Yes.  PDP11GUI allows you to transfer a block-for-block image of a disk that both SimH and QBone/Unibone can use (and to write a disk image back to a real disk drive, as well.)

JRJ

[Jay Cotton]

Well, it looks like I hit the sweet spot.

I have the RQDX3 controller and RD31 drives.  So based on the link above

the ball is in the simh court.

The issues I am directly working on is, I need the NC driver and the DD driver on my hard drive.

I spent some time looking at kermit for rt11 (too big a byte)  and I have ordered a qbone but I

don't expect to get that until Feb.  

Does anyone have a quick reliable way to move *.sys files to a hard drive ?

tnx

jc

[Alison Telford]

Hi all! Happy New Year!

This is an off-topic query to Ashlin's off-topic post :) and is directed prmarily at them, though all advice extremely welcome!

Hi Ashlin! I recently acquired two almost identical microvax II systems, one with a dead RD54 mfm drive (RQDX3 controller) and another with a working ESDI drive (I forget the branding) hooked up to a Dilog controller. I'm working to save the image off the ESDI drive via TK50s, but given how flaky they're being (I'm learning a lot about the internals of both the drive units and the tape cartridges, as I've had a drive attempt to eat two so far), it may or may not succeed. I have one of David's MFM emulators set up connected to the RQDX3, waiting for an image.

ANYWAY, I had found your Tephra blog post on getting a uVMS install loaded onto a microvax II. I was hoping to cheat, so I tried out the images you had made available there on the emulator, but sadly my Microvax II hates them, (complains of either missing boot sector, invalid media, etc etc). I'm VERY likely doing something dumb -- would it be OK to take this offline and email you directly on it? Or we can continue the discussion here or open a new thread in the forums, I'm easy! I just a) don't want to hijack things, and b) don't want to come at you out of the blue :) Advice, thoughts most welcome!

Cheers and regards, Alison Telford

To view this discussion visit https://groups.google.com/d/msgid/mfm-discuss/CANmz1%2B1DJKf5hUOP8%2B-MWrYzaR4v_exbQSCrjS9OGc%2B1AX6pXA%40mail.gmail.com.

[Jay Cotton]

I will start with what I have working now.

I made a transition file of the RD32 (?) st251 disk.  I was able to create a bootable copy of that for the mfm emulator.

For reasons, I can't seem to link anything.

Now, I have the ability to connect the tu58fs emulator on the second serial line.  This works, I can copy files into the 

mfm emulator disk image using the pdp11 h/w. 

Now I have a rt11 update I want to install.  And I am hitting a wall of sorts.

The tu58fs emulator can be sized as needed, so 10M seems about right.  

If I modify the DD.SYS driver I expect I can read it the 10M tu58 (format) tape image (TBD).

Not so certain about simh.  It has a copy of dd.sys on board, and I think I need to modify it

to work with 10m of space on the tape image.   This is a catch 22 also, since to edit the dd.mac source

file.

However, I have a disk image of the update running on simh and given that I have the RQDX3 controller 

is there anyway go get that to work?  Or should I keep pushing on the tu58 tape solution ?

I feel like I am missing something obvious.

TNX

JC

[cub...@gmail.com]

What do you mean by "I can't seem to link anything"??

10MB would be way bigger than I'd expect you would need for an RT11 update.    EXACTLY what form is this "update" in?   Is it another disk image that you want to copy files from?  A RT11 update distribution?  Just what is it?  Where did it come from.  What is its history?

Not sure exactly what you are asking on that last question. Is it a disk image of files for an update?  Is it a copy of your disk with the update applied?  what is it?

An examination of the source for the DD driver would quickly tell you if it cares about the number of blocks in the input tape.

Overall, I think your best way forward would be to:

1) Use PDP11GUI to transfer an image of your existing disk on your PC that you can use with SimH

2) Make a copy of that image on your PC to play with.

2) Do whatever you need to do to the copy under SimH and test the results.

3) Use PDP11GUI to transfer the results back over your existing disk.

Another way might be to:

1) Set up your emulator as a SECOND drive running on your real PDP-11 as a NEW DISK alongside the real disk drive.  (I'd suggest you start with a COPY of your existing emulated image. Otherwise you'd have to format it  and you might not have the program to do that on real hardware, or a way to load that program)

2) Use PDP11GUI to transfer the "update" to that new emulated disk on your real PDP-11.

3) Do whatever you need to do with your two drive system.

In general, it is a lot easier to get help when you describe your situation in detail and accurately.

JRJ