NEC PC-9801/PC-98 series: FDS disk writing?

[wyatt8740]

Hi, simple question.
I'm well versed in the traditional advice for writing disk system games using an old PC with a parallel port or some special copier devices. But I have a friend who is wanting to get into the Famicom herself, and she doesn't have any suitably slow IBM compatible PC's with parallel ports (her oldest are Pentium 4 at multiple gigahertz). I have an 8086-based AT&T 6300 that is probably suitable, and some 133MHz Pentiums, but I am many states away.

BUT: she does have an NEC PC-9821 Ce2, which uses a 25MHz 486SX CPU. The 98 series is not remotely IBM compatible, although it does run DOS. Since the PC-9801/9821 series was the de-facto standard in Japan "back in the day," I'm wondering if a program exists for that version of DOS to do disk copying.
I see that "I-Line PC" might be a thing that exists, but it depends on hardware I do not know how to make.

I guess I might be able to modify FDSLoadr's assembly code to use the right I/O ports for the PC-98, but I'm not super confident about my assembly abilities. Especially on a system where almost all the documentation is in Japanese, a language I am still weak in despite my best efforts. I do have my own 98 clone (Epson PC-486GR) that I could use for testing, however.

I've personally been using an FDSemu and a RAM adapter for a long time instead, but she really likes the idea of using original disks and I honestly can't blame her. I think it'd be fun, too.

Edit: looks like maybe according to the readme with FDSLoadr it was the first of its kind to do this, and it was written in around 2001. So maybe it hasn't got a parallel from the PC-98 era. Additionally it looks to use 386 and perhaps even pentium instructions, so the 486 may not work. Still, I'm interested to hear what people did back then to copy and author FDS disks in Japan domestically. I know about copiers, but that doesn't explain how homebrewers did it. Unless they were able to just write files to a 3.5" or 5.25" diskette and then have the copier write it to the quickdisk?
Edit 2: of course, maybe the rumours I've heard about it not working on newer computers only really means super modern ones. Maybe a pentium 4 is fine?

Edit 3: she also has a 9821 C200 (Cereb), which uses a 200MHz Pentium CPU. Forgot about that.

[P]

The FDSloadr is very unreliable and many people never get it to work fully.

Today you are much better off using FDSStick, FDSemu or FDSkey which can all write disks just like FDSloadr but without the need for a very specific computer. You already seem to have FDSemu so you probably just need a special cable for the disk drive. Tototek sells those for the FDSStick (I guess they use the same cable, but check out the pinout just in case).

The disk drive must be modded for disk writing as they have a write protect circuit (Tototek sells kits for those mods too).

And the usual warning that writing FDS disks are normally not recommended as they are highly likely to only work on the drive you wrote them on. I'd only write over disks that doesn't load anymore.



I don't know what pirates did besides using various types of copiers, but I do know how developers made the games. First they would program the games on a computer and transfer them to a white prototype FDS disk so that it can be tested on a Famicom. The FDS disk drives doesn't seem to be any different from the commercial ones except that the write protection circuit would of course be missing so that they could write disks. The drives would also be correctly calibrated (using an oscilloscope) so that the disks would work on all drives (this is a problem with home-written disks). They would just have to design a way to hook up the FDS disk drive to the computer and write software for handling it.
Computers were expensive at the time though so probably not all developers always had access to computers and a lot of the work were done on paper. They would also create their own development hardware from what they had, Sakurai infamously revealed in some interviews that he partly programmed Kirby using a modified HAL Trackball and Twin Famicom as a very crude development tool.

For debugging they would need a Famicom ICE (In-Circuit Emulator) which is a special variant of the Famicom with extra debug capability (like memory monitoring, modification and breakpoints). The Intelligent Systems FDT ICE is such an official ICE that developers could buy from Intelligent Systems. Instead of a disk drive it has RAM that emulates the disk drive (similar to how the FDSStick/FDSemu/FDSkey works), this technique is called "RAM-disk", the developers would upload the game to the RAM-disk RAM and it acts like a real disk. As guessed in that thread the game can probably be uploaded from an FDS disk using the FDS disk drive cable attached in the front or from a 5.35" or 3.5" disk using the floppy disk drive connector in the back.
And this ICE wasn't just used to make FDS games, it was used to make any type of Famicom game as it was the quickest way to upload, monitor and even modify game code directly on the real hardware. Of course ROM cartridge games would eventually need to be reprogrammed for whatever mapper they would use and be tested on an EPROM cartridge with said mapper for the final testing, the ICE is mainly for debugging individual routines.

For SNES, Nintendo used a similar ICE which took only 3.5" disks.