The XXX file
Singer
Getting it onto the machine
USB stick, root folder. Futura series.
How the file is built
The header counts records, not stitches: a jump and a colour change each count as one, the same as a stitch. Count only the stitches and the file opens with the design cut short.
Colours
The palette is written into the header, so the machine shows the thread order up front.
If your machine is not listed
Use DST. Every commercial machine reads it, and most home machines will too — it is the format the trade falls back on. The stitches are identical in all seven; only the wrapper differs, so «which format?» is a question about your machine and never about quality.
Make a XXX file — see the stitches first
Written from our own writer for this format, in src/engine/format.