Wang MicroVP - HDD MFM Emulation

[nzkgb]

Hi all,

Hoping for some pointers around getting an image of a MFM drive from a Wang system.

I've recently acquired a Wang MicroVP system (Wang 2200) - This came with some terminals and the Data Storage cabinet, with a Maxtor XT-2190 drive.

Not much info out there on these, https://www.wang2200.org/docs/datasheet/2200MicroVP_DataSheet.715-0587.9-85.pdf

I'm trying to create a copy of the drive before it dies completely, using David Gesswein's emulator.

The issue/s I'm running into is that it doesn't read the drive correctly from what I can tell, analyze detects it as an Intel_iSBC_214_256B controller, with incorrect parameters

I've had some luck with setting things manually, it does look like the XT-2190 has 15 heads but I'm only getting results with setting 8 e.g

mfm_read --drive 1 -h 8 -c 1224 --transitions_file wang_microvp_transitions.raw

Then converting to an emu image

mfm_util -a -t wang_microvp_transitions3.raw  --extracted_data_file wang_microvp_extracted.img

It gets part way through then fails:

ECC Corrections on cylinder 271 head 1: 29(3)
Failed to read word from transition file 0 4

The resulting file is about 18mb, I can run this with the emulator and the system loads initially, but if I try to access more it fails to read:

  Waiting, seek time 5.0 ms max 5.1 min free buffers 200
  Drive 0 Cyl 9->901 select 1, head 0 dirty 0
Failed to read emulation cylinder rc 0

From info that I can find, it seems the system can only access 16mb of storage at a time, so a larger drive is broken down/formatted into "platters".

I assume there is some Wang specific quirks around this which haven't made it into the MFM software, but maybe there's some options around manually configuring this, if anyone has some pointers/info? would be appreciated!

 

[pbirkel]

Have you tried mfm-discuss@googlegroups.com ?
David is very responsive there, as are others.

 

[nzkgb]

Thank you pbirkel, I've posted there now and David has given some pointers on what to try.

I'll report back here with any success.

 

[vhauffmr]

Congratulations on getting tour hands in a working vp System.
Apart of the mfm emulator a group here in germany developed a disk emulator for the 2200 that you can use as you would the disk cabinet.

If interested I could send you one to try.
Then all you’d have to do is copy the contents block by block which is about 10 lines in Wang Basic. Of course you’d need a second 6541 disk card in the system.

As Jim Battle was kind enough to send me all his spares I do have quite a number of them so if necessary let me know.

And yes we are all just trying to keep our systems running so not looking for financial compensation here. I did promise Jim I’d use the spares to help others in need.

Yours,
Martin von Hauff

 

[nzkgb]

Thank you Martin for the information and offer, I would be very interested in trying the disk emulator!

Fortunately my Micro VP system has 3 disk controller cards.

I am based in New Zealand, hopefully the the logistics wouldn't be too problematic. If you message me the details/price we could go from there.

 

[nzkgb]

Regarding the system, I've managed to create a working emulation image to use with the MFM Emulator.

I got some great help and pointers from David in the Google Group.

I had to:

Image the drive in parts to get 4 raw transitions files, as on 3 certain cylinders I would get errors (errors in original post) no matter what settings/tweaks I tried - this was done by editing the drive.c code to select which cylinders to image.

(with the help of an LLM since my C knowledge is minimal) Created a util to create blank transitions files for these specific missing cylinders, another util to merge all the files together, (imaged + blank files) to get a usauble transitions file that could then produce a usable emulation file

There is some missing data but luckily it doesn't appear to be critical for the system to function, I was able to boot the original system of the HDD, this is a modified version of Wang Multiuser Basic, modified and sold by PROCOM software in New Zealand.

My next issue is being able to log in as it's password protected and I haven't found a way to get around it yet.... But at least I can boot into Basic from a flash drive and see all the files/programs on the original disk.


I also learned some more about the hard drive/controller setup - the one in the Wang MicroVP system is only able to address 8 heads, and can only see up to 1024 sectors (from what I understand) - so the drive wasn't being used to it's full potential for ~160mb.

 

[vhauffmr]

Thank you Martin for the information and offer, I would be very interested in trying the disk emulator!

Fortunately my Micro VP system has 3 disk controller cards.

I am based in New Zealand, hopefully the the logistics wouldn't be too problematic. If you message me the details/price we could go from there

My email is: martin@vonhauff.de

If you send me your address I’ll be happy to send you a unit. Rather than payment could I ask for an image of your disk?
I’d be most interested in a modified wang Basic.

Yours,
Martin

 

[nzkgb]

I have sent an email with the image link and details.

Thank you again.