TRS-80 DMK image support

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mvcbe
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Joined: Thu May 02, 2013 9:06 am

TRS-80 DMK image support

Post by mvcbe » Mon May 06, 2013 8:11 pm

I'm the proud owner of a Rev. C KryoFlux and I'm impressed by its ease of use. After some fiddling with the USB ports on my Mac the device just works. The only real problem is the weird diskette format used by my old Tandy Radio Shack TRS-80 clone. Most of my disks are formatted in NewDOS/80 2.0 DSDD format with a single density track 0 and a total of 81 tracks (from which 80 are user visible, track 0 is only read during boot). What I'm doing now to read the data off the disks and convert them to DMK format used by my TRS-80 emulators or disk access utilities (see link below) is a multi step process:

1. Read the disk in DTC preservation format
2. Convert track 0 to an FM sector image
3. Convert the rest to an MFM sector image
4. DD this to a single mixed sector image
5. Use a C program to recreate a DMK image

This is neither completely automatic nor close enough to the original formatting of the disks for special cases such as copy protected disks which use fake CRCs, custom sector sizes, or otherwise unreadable data to identify the original software. The DMK format should be able to support any of these but I'd need a way to recover the original FM/MFM stream of bytes from the KryoFlux stream files. The sector image format looses all meta information which I have to recreate in a standard way. I've done this only for the format actually used by my disks but the TRS-80 operating systems supported a plethora of variants thereof.

I would dream of built-in DMK file support in DTC, but a raw FM/MFM read mode would help to create my own converter. This is what the KryoFlux is all about, isn't it?

WayBack link to the DMK file format description by David Keil (the original page is long gone :()
Ira Goldklang's TRS-80 Revived Site

Marcus von Cube
http://www.mvcsys.de

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IFW
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Joined: Mon Nov 08, 2010 2:42 pm

Re: TRS-80 DMK image support

Post by IFW » Tue May 07, 2013 4:02 pm

For writing copy-protected disks we support IPF as an universal, extensible, platform-agnostic and protection-agnostic format instead of supporting millions of attempts capturing data that simply can't be all correctly represented without representing the mastering content and the context at the same time - which no other format does, therefore there is always a need of work arounds and hacks and supporting tons of specific cases for various disks.

The only exception to this rule is G64, but even for that DTC generates a custom, extended G64 file that holds more information than a normal file does.

There is no plan at the moment for formats specific to certain emulators only, unless it really benefits many KryoFlux users (like G64 does).
However, it is planned to have a serialized format specifically for FM and MFM disks that collects data from a track during analysis; this is especially useful for comparison, but I think it's exactly what you need as well.

You could either use this serialized track data which will be obviously easier to process than flux reversal signals (what DTC does) - once available. The content will be very similar to what you'd have via the various Track Read commands on FDCs like the WD-177x, except for the fact that the original track data won't be altered, like e.g. the Address Mark detector modifying certain bitcell sequences on WD chips.
Alternatively, you could use the stream files directly as well, but correctly translating flux reversals into data is not trivial to get right.

Should you choose to use the planned serialized format, your feedback would be more than welcome on exactly what you'd need. ;)

mvcbe
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Joined: Thu May 02, 2013 9:06 am

Re: TRS-80 DMK image support

Post by mvcbe » Tue May 07, 2013 5:06 pm

I guess the serialized format will fit my needs. Do you have any time line? I don't think I want to put my hands on the stream files ;).

Is IPF a supported output format? I was thinking it is meant for authoring or archival purposes in order to reproduce salvaged disks as closely as possible.

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mr.vince
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Joined: Tue Oct 05, 2010 5:48 pm

Re: TRS-80 DMK image support

Post by mr.vince » Tue May 07, 2013 5:21 pm

There's a free implementation (see dev / 3rd party section), and the Softpres Analyser also creates IPFs. But this is a separate software package, which is not included in KryoFlux.

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IFW
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Re: TRS-80 DMK image support

Post by IFW » Tue May 07, 2013 5:27 pm

No ETA yet, but it's definitely planned as it is needed for a few things, most notably comparing protected, but not duplicated games like many of the disks released in Japan.

IPF files generally require an authoring tool, so dumps submitted for preservation to SPS will have "official" IPF files. There is an alternate encoder out there though written by one forum member here for the purpose of creating the file itself from a stream dump - obviously not authoring the content, but for "home use". ;)

toml_12953
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Joined: Fri Nov 13, 2015 3:36 pm

Re: TRS-80 DMK image support

Post by toml_12953 » Mon Feb 08, 2016 8:58 pm

Any progress on DMK files yet? I don't even need to copy protected disks, just standard disks like Model I TRSDOS, FORTRAN, etc. TRSDOS 2.8DD might be a problem, though. The first track (Track 0) is single density so they can be read by the ROM routines which don't know how to read double density but the rest are double density.

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IFW
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Re: TRS-80 DMK image support

Post by IFW » Tue Feb 09, 2016 1:26 pm

You can still convert the stream files as required as per the first post here.
More automated solution will be available once user defined formats are available in DTC.

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