Image 3" floppy disks for emulator

Started by nivrig, 01:18, 19 October 11

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I've been clearing out my parents' attic recently and uncovered a treasure trove of CPC hardware, books, tapes and disks that I'd forgotten about (some pictures here if you're interested).

So I now have a DDI-1 / FDI-1 3" drive and a carrier bag full of disks. Assuming I can get the drive to work, what's the best way for me to image the disks for use in emulators? I guess they are mostly in standard AMSDOS format, but some could possibly be RoDOS or RAMDOS too.

I think I read somewhere that I could connect the FDI-1 to my PC as a regular floppy if I set the BIOS to expect a 360k 5.25" drive. Is that correct? If so, what software should I use to access / image the disks?

I expect most of the disks are blank or contain tape games transferred to disk, but I'm fairly sure some of them contain original games I wrote so I'm quite keen to rescue them!


I have a KryoFlux controller, but there's no way at present for it to output CPC disk images apart from as raw MFM dumps. Using the 464 probably isn't an option either as the cables that connect the CPC and monitor are broken and the connectors missing.

Thanks :)


You got Pascal on ROM? Pretty cool, never heart about that :-)
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus


We NEED a dump of that Pascal ROM! :) If you can't do it, send it to me. Nice ROMBoards and Multiface II too.

Connecting the FD-1 to a PC isn't that easy, it needs to be a pretty old PC with an old DOS / Win98 installed as far as I know.



With the KryoFlux, that's quite easy, just plug'n'play, if you'd like to add a 3" drive to your PC, then it's a bit more complicated, but not that much  ;D


Quote from: girv on 01:18, 19 October 11
I have a KryoFlux controller, but there's no way at present for it to output CPC disk images apart from as raw MFM dumps. Using the 464 probably isn't an option either as the cables that connect the CPC and monitor are broken and the connectors missing.

It would be nice to at least get some emulators capable of reading KyroFlux raw dumps. Do you have information on the format that's used?


I imagine I'd need to boot the CPC to dump that ROM, and I'd need to fix the monitor first...might be calling on your services.

@robcfg @Executioner
I've been able to dump some 3" AMSDOS CPC disks as KryoFlux format 4. This is some form of MFM dump but I have no further information than this. MFM decoders are pretty easy to write though, so if I can get the layout information...

The only CPC emulator to support IPF files is a modified version of Caprice32:

Creating IPFs from KryoFlux dumps is a manual process done by SPS specialists. SPS don't release IPFs, they only go back to the people who supplied the raw dumps, and I haven't been able to find any publicly available CPC IPFs :/


I fall else fails, if there's specific disks you'd like to image (and not the entire bag!), someone with an HxC floppy emulator could do it very easily. I can do it if you're willing to post them...

Oh, wait, how do you go about converting hfe images back to dsk? Has Jeff released a tool?


Quote from: Gryzor on 10:18, 20 October 11someone with an HxC floppy emulator could do it very easily.

How would that work?

It would be a whole bag of disks that I'd like to image  ;D


Quote from: girv on 10:50, 20 October 11

How would that work?

It would be a whole bag of disks that I'd like to image  ;D

Insert disk in internal drive, insert an empty disk image to the HxC emulator, copy the disk from A to B.

Only problem is, the resulting image is not a simple dsk but a format that the HxC board uses, and I don't know if there's a way to revert to dsk afterwards. I'll try to find out, if you're willing to pay postage for the entire bag :D


Ah, so I'm back to needing to repair the CPC monitor. I'll need pinouts, a DIN and a power plug, a soldering iron and a bit of luck.

I could pay postage for the bag all right. On the other hand, the HxC looks like fun and the HFE format is well documented on the site...

Cheers. It's another option if the KryoFlux route is a no-go.


Ok then, at your sercice if needed :)


I am currently using an FD-1 connected directly to my PC (you need to remove the 5v line that goes to the ribbon cable inside the FD-1 though).

CPCDiskXP has been working OK for me so far even though my motherboard bios does not allow me to specify the floppy drive as a 5.25". I have only been transfering Tatung Einstein disks with it though but there should be no reason why that shouldnt work with Amstrad disks as well.


That sounds like a fairly simple solution - so you have any details on the 5v line mod required?

There's also SamDisk which looks to be much the same thing as CPCDiskXP.


SamDisk has been discussed here before, it has worked fine for me in the past...


To copy 3in discs to PC it's easier to connect a normal 3.5in disc to the CPC than a HxC and copy the discs over that way.

@Girv: Send me a PM and we can talk about hardware repair / ROM rescuing.





KryoFlux "DTC" program can actually dump in a number of formats. Just not DSK or EDSK (yet?).

The "rawest" one would be the STREAM format, which (I believe) is a multiply redundant dump of the magnetic flux transitions on the disk surface in the format used internally by the KryoFlux hardware. There is a another format in development called DRAFT, which is something similar but not tied to the KryoFlux.

Both of these perfectly capture all types of protection systems as they contain the raw data that the FDC would actually see and decode. The file format specifications are or will be made open.

Some work has been done around STREAM for Atari ST:

There is a higher level MFM format which seems able to dump AMSDOS disks nicely. I don't know the precise specifications of it, but it might be possible to find out or even guess. I've written plenty of MFM decoders on Amiga ;)


Quote from: phi2x on 12:11, 20 October 11
Do you think it would be a good file format regarding weak sectors emulation?

That could pose a problem, unless Kyroflux reads each track multiple times and we can compare to find the weak sectors.


Quote from: Executioner on 03:21, 21 October 11
That could pose a problem, unless Kyroflux reads each track multiple times and we can compare to find the weak sectors.

It does - 5 times IIRC - for just that reason.


Quote from: girv on 10:55, 21 October 11
It does - 5 times IIRC - for just that reason.

They must be rather large images then, since uncompressed MFM samples are going to be at least 150K x 5 per track to have any sort of reasonable sample rate.


Did your Amiga Atoms game appear on an Amiga Format coverdisk too? (I don't remember buying Amiga One, but it's possible I did...)

I remember getting that game on an Amiga coverdisk, thinking it was awesome and porting it to Windows 3.0 when Windows 3.0 first came out...  ;D Despite it becoming quite a hit at school with everyone playing it in our brand new computer lab, I've absolutely no idea what ever happened to it since - I doubt I even have a copy myself anymore...  :o

Anyway, glad to see you've kept all your CPC stuff. Sadly, I sold all of my CPC stuff to fund my Amiga purchase and now I'm into the CPC scene again, I'm gutted. I've even found a few tapes of source which still have all the names of programs I wrote written on, but which have sadly been recorded over with some Radio 1 nonsense.  :'(


IPF will come to be open.
Better to use an existing file format, instead of reinvent the well...
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)


Hi Girv, thanks for you answer over at the Kryoflux forum.

Anyways, the MFM dumps are actually quite small if all you do is use the -i4 format. Like i made a dump of my Bridge Player 3 disc (side A only 180kb) side ends up being 360kb large MFM file.
In case anyone feels brave and want a look, ive uploaded the dump here along with the output log and a dsk i made of the same side earlier using xeror/hxc:
or here:
or here:

Pretty sure the game is completely unprotected (so no weird gaps or anything). Note that the mfm dump may have 41 tracks '(one extra track) and the last 41th track shows up as unformatted (as expected). Most of the disc is also just empty space too.

Anyways, Kryoflux has 15 different (and adjustable) formats to dump floppies in so if this this MFM format isnt good enough we can try different format (even tho im guessing that this is ok for just dumping unprotected data discs). I must admit i probably bought a kryoflux board a little hastely (about last christmas) but with the ability to write back amiga IPF floppies (these are thankfully available on the net) being released last month and the IPF decoder sourcecode being released last week .. its much more worth it now.
Still, not really worth it for amstrad people untill you can get a usefull DSK yourself from its dumps.

EDIT: Oh, and if you are noughty and rename the mfm file to .img and load it up in HxC software it actually get recognised as a odd 40 track (but with 2 sides?). Outputting to dsk from hxc actually didnt make any errors either but loading up the dsk you can clearly see something is wrong (but got a partial file-catalogue so it cant be far off)  :D


Quote from: TotO on 14:53, 22 October 11
IPF will come to be open.

IPF is open now, but the problem is that no one outside of SPS can make IPF files.




I dumped a couple of standard DATA format disks using KryoFlux's DTC tool:
dtc -fdisk.mfm -g0 -e39 -l8 -i4

The disk.mfm dump file was 360k but only the first 180k contained data, the rest was zeroes (180k is the expected length of the data on a DATA disk - 40 tracks * 9 sectors * 512 bytes). Viewing the file in a hex editor, it appeared to be the decoded data without any header information (track, sector number etc.). The trick was that there is no sector interleave - the data had been rearranged to be in the correct order.

So, using the HxC software:

  • Set up the "Load Raw Image" options as shown in the attached image
    or use the attached HxC profile settings.
  • Click "Load RAW file" and load the disk.mfm created with DTC above
  • Click "Export" and save as CPC DSK
  • Done!

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