[cctalk] Re: Connecting MFM emulator as both 1st and 2nd drive in Microvax 2000?

On Sat, 12 Aug 2023, Nigel Johnson Ham via cctalk wrote: Thank you! I wasn't in the DEC world, so I appreciate your taaking the time to tell me. I did much more work with varying types of floppy drives, and not so much hard drives. Floppy drives are commonly called DS0 - DS2, with a few exceptions. https://old.pinouts.ru/HD/InternalDisk_pinout.shtml http://www.interfacebus.com/PC_Floppy_Drive_PinOut.html But, the Shugart SA400 OEM manual calls them DS1-DS3 https://deramp.com/downloads/floppy_drives/shugart/SA400%20OEM%20Manual.pdf http://www.bitsavers.org/pdf/shugart/SA4xx/SA455_SA465_Service.pdf https://deramp.com/downloads/floppy_drives/shugart/SA800%20OEM%20Manual.pdf And the Teac Specifiation calls them DS0-DS3 http://www.bitsavers.org/pdf/teac/FD-235HF-A529_A540_A591_Specification_Rev… https://deramp.com/downloads/floppy_drives/teac/TEAC%20FD-55GFR.pdf Just to keep it confusing, PC jumpers all floppy drives on the second position, pin 12 of the SA400 pinout (DS1 of 0-3 or DS2 of 1-4), and then selects by the cable. TRS80 set all floppy drive select jumpers ON, and used a cable with only one of the drive select lines present in the drive connector, to also select by the cable. Fourth drive (DS3/DS4) had some complications, as some systems re-defined that pin of the cable for other uses. But, I located the Seagate ST506/412 OEM manual https://minuszerodegrees.net/manuals/Seagate/Seagate%20ST506%20ST412%20-%20… and, as you said, the drive selects are shown as DS1-DS4. Wikipedia, however, calls them "DRV SLCT 0" - "DRV SLCT 3" in its diagram of pinout https://en.wikipedia.org/wiki/ST506/ST412 https://en.wikipedia.org/wiki/ST506/ST412#Connector_pinouts -- Grumpy Ol' Fred cisin(a)xenosoft.com