Mixed-density raw images with USB HxC2001

[mrvmurray]

Hi folks

I need to get the USB HxC2001 to present a drive in a slightly strange way. The computer that will read the disk is an utterly ancient TRS-80 Color Computer (CoCo) workalike (well, mostly). Its not a CoCo, its a kit-built thing with off-the-shelf 80-cylinder floppies.

The standard format for the OS (FLEX 09) is that track 0, side 0 is FM(SD), all other tracks/sides are MFM(DD). Sectors are 256 bytes, and there can be 16 or 18 sectors per track per side (or 10 for track 0 side 0).

I have raw dumps of some disks. These are just the data in the correct order with no metadata, no headers or anything else. I can read them with the HxC USB driver software, but how do I make track 0 side 0 FM(SD) and the rest MFM(DD)?

Thanks!

M

[mrvmurray]

Answer found!

The trick is to define the emulated floppy structure with an XML file. I couldn't find the XML file docs anywhere, so I had to find out the details by experimentation.

M

[Jeff]

Exactly !

[chapmro]

Any chance you could post the XML? I need to do the same thing for 8" Advanced Digital Corp disks, which are track 0 FM, other 76 tracks MFM (I think it is also called IBM 3740 double density format)

[spt87a]

Old thread......

I think this is what I need for my TRS-80 issues. I loaded a Model 1 DMK of a bootable OS disk then exported to XML. OS is TRSDOS 2.7 which is for double density so it should have a SD track 0 sector 0 and the remainder of the disk is DD.

Looking at the XML I don't see anything defining sector 0 as SD (FM). I see the track is defined as IBM_MFM. What in the XML would indicate the density of that sector is different?

[spt87a]

For track 0 I tried removing the <format>IBM_MFM</format> from the track and added that to each sector with sector 0 being IBM_FM instead but the Floppy Emulator tool (2.16.10.1) will not load that.

[spt87a]

Ok, well I found a work around but it involves using a Gotek.

Using this, I can take a blank SSDD40 HFE file, copy the mixed density boot disk to it (in this case Games Pack 2) using CopyCat and it will boot fine. I can move the resulting HFE file over to the Lotharek HxC and it will also boot fine.

This is HFE v1.

I assume this is a quirk or bug in the HxC firmware.

[Jeff]

Looking at the XML I don't see anything defining sector 0 as SD (FM). I see the track is defined as IBM_MFM. What in the XML would indicate the density of that sector is different?

This new release now allows you to specify the <format> tag for each sectors :

https://github.com/jfdelnero/HxCFloppyE ... V2_16_11_1

20 February 2025 : HxCFloppyEmulator v2.16.11.1

-> XML export/import :
Better multi-format tracks support.
You can now specify/change the density/format for each
individual sector with the tag.

(the export now also automatically add the format tag if needed/different)

[spt87a]

Ok, great - I'll take a look at that.