ST-506/412 to IDE/ATA/SCSI/? adaptor

There has been a lot of discussion on this subject and I have tried to read all of it, but I may have missed a discussion of what I think is the key problem in such a product. Apologies in advance if I am repeating something As I recall you could not move a formatted ST506/412 HDD between controllers without first reformatting. This is because the gap and header information was likely different between different controller manufacturers. This particularly applies to ECC but could include simple things like address mark, sync byte, etc. So although your IDE drive gives you error free data and a crystal will give you perfect serial timing (no pll required and the pll in the controller never sees bit shift) the adaptor would have to synthesize the particular format down to the bit and including the specific ECC/CRC or the controller will post an error. Since most of the ST506/412 controllers after the early ones were "picocoded" state machines that did the serializing/deserialing I suspect most any modern dsp can do the work, the real problem may turn out to be getting the format information for the particular manufacturer and model controller chip used in the system to which the adaptor attaches. Even within manufacturers the format changed with generations and some manufacturers did custom variants, some of which were rumored to be designed to preclude generic ST506/412 drive attachment. I suppose a very smart machine could learn by having a series of known data patterns written to it, but that seems challenging. So it may turn out to be an impossible task for other than the high volume commercial controller chips and even there finding the specific ECC algorithm might be difficult. Just my 2 cents Tom