When I updated my VF II Web page late Dec 2019, I contacted Roger Hanscom to tell him about 
publishing our discussion. He replied Jan 1 2010 as follows:

Thanks for the update on the Versafloppy II stuff.  Not sure what all I told you about what I was doing, so forgive me if I repeat.  

I got Monahan's VF II [diagnostic] utility to work with 3.5" drives.  I was particularly interested in the diskette format that most closely resembles PC format, so I had to do some restructuring of his device tables for that.  But it worked.  I then tried to isolate a few routines with the idea that they might be used in a CBIOS.  That worked as well.  Monahan's utility is quite large because it attempts to adapt to quite a number of formats.  I was able to pare it down a lot just to do reads and writes to the floppy format I wanted to work with.  All that extra format stuff wasn't a good idea for a CBIOS in only 64k (IMO).  

Sadly, my first attempt at a CBIOS was a bust, but I was still hopeful.  At that point I put the project down because some other things were on my plate. My eventual intent was to get to the point where the SBC-200 would have a CBIOS that supported 3.5" floppies, and then I could try to substitute a Gotek drive for the conventional 3.5" floppy, but I never got there.

So, please let me tell you what has been going on with my SD Systems box.  I have a SBC-200, along with a Digital Research Computers home built 64k static memory card.  I use the serial port (8251A based) on the SBC-200 for a console.  The downside is 9600 baud is the best it will do.  I have been trying all sorts of ways to add storage (the floppy experiment was one!).

I have a couple of versions of the S-100 computer group's IDE (CF) cards, and I spent a lot of time trying to get one of them to work with the SBC-200.  I finally did that, so now the SBC-200 has sixteen 8MB "disk drives" in a Transcend compact flash module.  Still, getting files and data *into* the SBC-200 system was problematic (moving things the other way is quite a bit easier!).  I pulled out a serial card that I had (again, it is home built from the S-100computers group).  It uses a 8530 UART ( 2 ports, capable of up to 38,400 baud), AND has a USB interface!  I got the USB port working, and now I can copy files (via XMODEM protocol) to the SBC-200.  It is incredibly fast.  I set the baud rate of the transmitter (Linux PC) to 115k baud, and then stand back!  

I suppose I might not give up on the idea of a floppy, but it seems overtaken by events at this point.  I can manipulate the file systems on the compact flash with "cpmtools" and Linux "dd".  So backing up the contents of the compact flash is pretty easy, as well as creating new file systems to load onto compact flash that the SBC-200 can recognize and work with.  Loading files, via USB, is pretty easy too.

So -- I have a 4-card S-100 "powerhouse" now!  In the past, I ignored all but the most necessary Z80 applications that can be found in all the on-line repositories because of the pain and suffering of trying to load them onto the SBC-200.  Now I'm exploring lots of the great software that is "out there".  It is easy and fast to load things, and I have all sorts of storage to play around with them.  If they are junk, or don't work (and I can't fix them), then it is a simple matter to delete them and move on to others.

SO .... that's the story from here.  I hope you are doing well, and that 2020 will be a great year for you!! - Roger

[later Roger added:]

This [experiment.z80] is what I was able to find [on more fixes to the VF II diagnostic code].  Looking at the dates on the files, I was working on this a year ago!  No wonder I can't remember much. The attached code worked as I remember it.  I was trying to remove as much of the "extra" code in the original VFII diagnostic as possible.  This program has everything but the read a sector and write a sector options removed (plus only works with a 3.5" drive with a PC-like format).  It is still quite large, so I'm reasonably certain that much more could be eliminated.  It is about a quarter of the size of the original diagnostic.

As you can no doubt tell from what I left in it, I was working toward being able to incorporate disk read and write routines into some sort of a CBIOS. Hope it is useful. - Roger