Decoding Melco Embroidery Disk Format

 I did not get any documentation along with the pattern disks to tell me whats on them, the printed labels only give me filename codes but nothing more. The pattern distribution company does exist still, and i can search their website to look up patterns which is helpful but dealing with hundreds of floppies is not particularly practical.

This is a perfect excuse to test out my greaseweazel, i can't read the floppies directly without using EDS III which likes to crash alot for some reason or another. I think the copy protection dongle that plugs into the parallel port might be dying, whatever the case i can just read the disks as analog and rebuild the data as raw disk images and just extract the files from the images after sorting out the filesystem structure. 

It takes roughly 80 seconds per disk so this should take somewhere around 17 hours just reading disks continuously.

The filesystem itself just seems to be some sort of FAT12 derivative, im pretty sure alot of this dates from the mid 80s so its not too complicated. The first 16 bytes of the disk just indicates the number or sectors the disk has plus the starting address of the file table. Each 16 byte line of the file table provides a filename, length in bytes and starting position of the sector that stores a list of sector addresses the file occupies. The sector size is 256 bytes, 80 tracks, 9 sectors per track.

It only took me a few hours to sort though the file-structure after building a few disk images and comparing it to some files exported using the existing software. The CND files themselves are a type of vector format, which needs to be converted into actual stitch values to be used by the machine.

It only took about 60 lines of python and i was able to extract the files, so all i need to do is suffer through reading all of the disks and build a database of all the files so i can sort of whats what. I found a python embroidery package that i might be able to use to generate preview images and convert to other formats. Which would be useful since i found a few cases where the previous owner overwrote some of the original pattern files on some of the disks so even by filename i won't be guaranteed to know what I'll find.

Embroidery Machine Restoration

My most recent barn find ended up being a Melco EMC6-MTL embroidery machine, complete with an old celeron 500 "never obsolete" emachines computer with a copy of EDS III and roughly 750 floppy disks worth of patterns.

I am not sure how long the machine ended up sitting, but i ended up taking several weeks digging around for service manuals, scrubbing off years of sewing machine oil and cleaning several decades of lint and grime off of everything. As far as i can tell, the machine itself was well maintained and is in working condition but needs some much needed servicing to get it running smoothly.

I was not exaggerating about the number of floppies, there are boxes labeled 1 - 750 dual density disks and possibly just under ten thousand random patterns. Lots of fonts, random generic sports logos and themed collections such as holidays and whatnot. The disks themselves are some sort of proprietary format that can only be read by some commercial software, more on that later.

I was looking for a project to keep me busy, my plan is to make the machine operate headless and sort out exactly what i have on hand in pattern files.