Olivetti M20

Hi I finally have some success in getting a hard drive working on my M20 ( this is the machine with a Z8001 ). I wish to thank Tony, Berry and Fred for there input that helped along the way. I still have some issues but all have work arounds. 1. The BIOS sets the step rate too fast for the ST251. It seems to be around 2.5ms. I found the ST251 doesn't like more than 3ms. I wrote a program that I put on my boot floppy that sets it to 4.0ms. Does anyone know the correct step rate for the st251? I'll have to hack the BIOS some day to fix this. 2. The BIOS sets the precomp somewhere near cylinder 120. The st251 has no precomp and uses the pins as part of the head select. I've made a cut and jumper on my controller card to stop the RWC signal from going to the drive and the MFM generator chip. Again, this needs a BIOS hack. 3. I still don't know exactly where or the format of the bad sector map. I do know it is on one of the first 32 sectors and all 0's seems to indicate that there are no bad sectors. My drive has no bad sectors listed on the lable but if some else wants to use a st251 on the M20, they might need to know how to set this up. I had to do a couple of other hacks to the controller board I'm using but they are related to the boards original use ( a Tandy 5 Meg disk drive and controller ). I've not looked at the 5 Meg disk that came with it. It might have something interesting on it for the TRS80 folks but they most likely have everything someplace on the web already. We are still finding bits and pieces of code and documents for the M20's , even though there were many sold in Europe. M20's are just a little rare now. Most were sold to businesses and they tend to throw things out when they get obsolete. I'm always looking for more M20 owners that might have some software or manuals that can be added to the collection of items we are trying to save. I wonder if there are any more on this list? Dwight