Writing 8" floppies with SuperCard Pro

You and I were thinking of two different things: I was thinking of the reduced write current on the inside tracks, and you were thinking of changing the bit timing. On the latter point, I was incorrect. For reduced write current, all the controller does is to tell the drive whether or not it is on an inside track, the drive handles the rest. I note that the pin used for this varies from drive to drive. On a Shugart 850, this is on pin 2. On a Siemens FDD 100-8, this is on pin 16, so this is something that the original correspondent should check for each of his/her drives. The Shugart 801 does not seem to have this feature. Also, there is a model of the FDD 100-8C, which counts the tracks ON ITS OWN, and DOES handle this automatically, and that is where I got confused. There are also some 5" drives which do this, e.g. the Tandon 848, either using a signal from the controller (on pin 2) or on their own. Then, when this reduced write current signal is active-low, the drive reduces the write current. This is the "TRK 43" signal that the correspondent actually referred to. Most of my 8" floppy experience was with the single-density FD1771, which does NOT change the bit timing, and ONLY has this "TG43" signal. But, you are also right in that the later controllers, e.g., the FD 1791, for example, also provide two additional signals, "EARLY" and "LATE" for write precompensation. As you point out, these signals do not go to the drive, but instead are typically used inside the controller to change the timing of the write pulses. The correspondent should probably check with the SuperCard Pro folks to make sure BOTH have been implemented. It is quite possible neither have. On 8/12/2015 4:05 AM, Christian Corti wrote: