8" drive support on PC's

Well, I looked at the data sheet for the WD37C65, which used to be fairly common, and the answer is "sort of". Pin 39 is the one that you'd be interested in. It's an output labelled "/RWC,/RPM" and when it's low, and the controller is in Base Mode, it says it causes a reduced write current when bit density is increased towards the inner tracks, being active when track > 28 (I think that refers to 40-track drives, which would be 56 on an 80-track drive). This is very similar to to the TG43 signal, except for being relative to a different track, but it's not on the same pin as /DIRECTION (Pin 31). I can't help wondering if "28" is a misprint for "23" or something like that, but I checked two separate printings of the data sheet and both said "28". It also says this function changes when in AT/EISA mode (it then becomes completely under program control, and appears to be intended to be used to set the density and/or speed for the whole disk) :-( However, if you have control over the FDC rather than letting the BIOS or DOS do it for you, you could make it do what you wanted. I also looked at the Intel 82078 FDC, which is a successor to the 8272, in either a 64-pin QFP package or a 44-pin PLCC, either 5V or 3.3V,. and it was an antecedent of many of the multi-I/O chips. Unfortunately it doesn't give enough detail. Lastly, I looked at the NatSemi DP8473. It has /DIRECTION on pin 4 (PLCC version), and /LC (low current) on pin 51. Pin 51 just goes high for HD media and low for SD/DD media (actually it goes low when 250kbps or 300kbps data rates are set, instead of 500kbps). So it doesn't look like that does what you'd want, either. -- Pete Peter Turnbull Network Manager University of York