On 10/05/2018 05:42 PM, Fred Cisin via cctalk wrote: >> On 10/5/18 4:21 PM, Chuck Guzis via cctalk wrote: >>> I seem to remember that there was a "combo" manual that covered the >>> 51/52, 91/82 and 101/102. Also, there was a 52M, but I never >>> encountered it in the wild. > > On Fri, 5 Oct 2018, Al Kossow via cctalk wrote: >> double sided 48tpi, with some micropolis-unique feature?
Again, I don't recall. I do have a couple of 100 tpi MPI 5.25" drives--I'm just not sure about what they're called. Micropolis interface also, IIRC, had a *slightly* different pinout from the standard Shugart SA400. (pause while he checks) Pin 2 - Head load Pin 6 - Ready Pin 34 Drive select 4 Just different enough to make for a little confusion. I do have a Tandon TM-100-4M here with a "96 TPI DSR" sticker under the latch, so the factory probably wasn't too careful about that. Of course, neither Tandon nor MPI produced a drive that was even close to Micropolis. But almost nobody was as expensive as Micropolis either. Micropolis never gave up, IIRC, on its 4-steps-per-cylinder precision leadscrew setup. I've got a Micropolis 1115-VI drive here and it's a heavy wonder to behold. The whole stepper motor, leadscrew and head assembly pivots on the drive door--usually, the stepper is attached to the main body of the drive. Further, it's a drive that features a microcontroller for drive spindle speed control (no adjustments) as well as for providing a "buffered seek" capability. Fire step pulses at it at rates slower than 6 msec/step and it behaves normally. Fire pulses at between 3-5 msec and the drive goes into buffered seek mode. It's a wonder to behold and, IIRC, was substantially more expensive than anyone else's 5.25" floppy drives. Sort of the antithesis of Jugi Tandon's "make 'em cheap" approach. No wonder Micropolis went out of the floppy business. --Chuck
