TESTFDC usage

I've found a working 5.25" 1.2MB drive (Mitsubishi MF504C-310MP) and a 3.5" 1.44MB drive (NEC FD1231T). Both drives can successfully format LD and HD media. I can fill disks and copy stuff off with no apparent issues. I'm booting DOS 6.22 off a 20MB partition on a 3GB drive. Dave Dunfield wrote: Before I go through a bunch of motherboards and find I've made an elementary mistake, I want to check that what I'm seeing is OK for a "typical" modern motherboard. FWIW this is a Gigabyte GA-7DXR+ and it takes Athlon/Athlon XP CPUs, the Super I/O controller is a VT82C686B ... just so you have an idea of what I've started with. I have the 5.25" drive as A: and the 3.5 drive as B: (and the BIOS has been told what they are). When I test the 3.5" drive I see a pass at 250k DD (with a 720K disk) and a pass at 500k DD (with a 1.44MB disk) and the other four cases fail. I think that means it can read/write the 720K and 1.44MB PC-style diskettes, so it doesn't buy me anything "odd" but the results do at least correspond with expected reality. When I test the 5.25" drive I see a pass at 300k DD (with a 360K disk) but with the 1.2MB disk I see three failures. I was expecting 500k DD to pass with a 1.2MB disk ... am I wrong? I've tried twice with the same results and I've reformatted the 1.2MB disk afterwards and in each case it formats with no errors. Are my expectations in error or am I slipping up somewhere? BTW: I'm not likely to find a fully-passing motherboard in the set of "modern" ones that I'm testing now. Any ideas how far back in time I need to go to find something that I can use as the basis of a "media archiving" machine? Most of the "PPP PPP PPP" ones are P1 systems. Although I have a bunch of older motherboards and processors, I'm not sure that I have "matching pairs" (or the docs to determine such, where separate components are involved). Ideally I'll find an add-in Adaptec board or similar, but, in case I don't, I'd like to minimise my search :-) Thanks Antonio