Most of this will be a re-run for anyone who has been on the forum very long, but for anyone new, here it is again.
Jeff and I seem to be doing approximately the same thing, although he on a parallel port and I on a serial port.
What I send over the serial port is usually just text, from marked blocks in the text editor on the PC. They could be anything the
workbench computer is expecting at that point. Usually it's Forth source code, sometimes assembly-language source code (in the format that my Forth kernel handles), sometimes an Intel Hex file, and rarely maybe something else I'm forgetting. The workbench computer just thinks you're typing this stuff in, lighting fast, without errors, and it handles it as it's coming in, not waiting for the end of the transmission before starting to process it. It could be doing something else at the same time. It doesn't care where it comes from, and although it usually comes from the DOS PC, I have also used my HP hand-held computers. Anything that can send out text on an RS-232 port. I suppose it could even be from a tape modem, as long as intelligible text comes out of it. The host computer thinks it's just sending the text to a serial printer. It wouldn't have to be text, but it virtually always is. I could for example load Forth words (via Forth source code text) for handling a binary file of some sort, then call that, and send the binary it's expecting.
It's hard for people to imagine how simple the method is. I really need to make a video of it. When NightmareTony was here, he kept looking for the "hidden part." There isn't any. No TSRs, nothing else running, etc.. (Wow, I can't believe he's been gone for over four years now!)
I've also sent info back to the PC in the Intel hex format, and used a GWBASIC program on the PC to accept it and put it in a file. My text editor (MultiEdit) has a terminal program that should work just as well or better, but I got accustomed to the other way before I had this editor, and it works, and I don't need to do this part often enough to learn a new way.
A method that came to mind from a post here yesterday was to use an (E)EPROM, assuming you have an (E)EPROM programmer on the PC. It's not as convenient as an SD card, but it sure beats typing and POKEing it all in every time like someone above mentioned.