flashx20 - Floppy and screen for the Epson HX-20

On Sun, 16 Dec 2018, Norbert Kehrer via cctalk wrote: That is especially interesting. It is probable that the HX-20 worked with the TF20 on a file level load and save, but the PX-8 was likely to work on a sector level. The HC-20s that I had were Japanese machines brought to USA for some software develpment in Berkeley. HudsonSoft? The HX20 never caught on very well in USA. It had a few dedicated applications, such as CableTV configuration. There was no technical documentation available. I had a little bit of incomplete Japanese documentation. During the time that I had some machines, the technical manual and protocol specification were unavailable in USA. I don't remember the disk format for the TF20 external drives, and they were unavailable in USA. IIRC, the only sample disk that I had used a form of the Microsoft "Stand-Alone BASIC", much closer to the NEC variants than the Coco. (seek center directory, with short directory entries that included a starting cluster number, and a linked list Granule Allocation Table (similar to MS-DOS FAT, and early Mac disk format) DSDD, with 16 256 byte sectors per track (320K) The Epson Geneva PX-8 had an external 3.5" floppy available, and CP/M! However, the PX-8 3.5" had 40 cylinders, with 67.5 tpi, instead of the common 80 cylinder 135 tpi of other 3.5" disks. Those 40 cylinder 3.5" drives are quite rare. I don't know about the track width; for reading, a PC can simply look at every other track. And formatting a virgin disk and writing to it should work. But, there is a definite possibility that RE-writing a PX-8 disk would result in one that the PX-8 couldn't handle (EXACTLY the same problem as RE-writing a 40 track 5.25" disk with an 80 track 5.25" drive) With appropriate format handling software on the PC, it should be possible for a PC connected using your system to work with actual Epson diskettes, and emulate the Epson external drives. Thank you for creating this! Now, I wish that I had been able to keep the HC-20s! -- Grumpy Ol' Fred cisin at xenosoft.com