FDS dumping/writing with MGD1

This is an archive of a topic from NESdev BBS, taken in mid-October 2019 before a server upgrade.
View original topic
FDS dumping/writing with MGD1
by on (#19539)
I'm not sure how well known this is, but it is possible to dump and write FDS disks with a Bung MGD1 and an MGD1<->PC Link cable. Tomy over at Tototek has written up a schematic from his cable and also has ported over the original Bung send utility to work under Windows with modern day PCs. The original utility is DOS only and written for PCs of years past.

I've gotten the software to work and discovered that the disks are dumped in a somewhat proprietary Bung format. There is a 3 byte header, which is 0x00 0x00 0x8Y, Y is the number of files contained in the disk image. I'm not sure why any of the high bits are set, but they are and they're always the same. There is also padding around the disk filename headers, which I believe is 16 bytes off the top of my head. There is a pair of 0x00s on either end.

I'm not sure how useful any of this information is to more than 10 people in the world, but I've written a utility to convert the Bung FDS images into standard FDS images with the 16 byte "FDS" file header that emulators can understand. I'm also working on writing a utility to go the other way so that FDS images can be taken off the net and written back to a disk via the MGD1.

I know every now and again this topic comes up, so I wanted to throw this information out there. I will keep everyone updated on my progress.

by on (#19694)
Well, I know it is potentially a big help for me, so I can't wait to see the app! But then, I already told you that and I just wanted to bump your thread, heh heh. :D