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Hugo Holden
October 16th, 2018, 03:30 PM
I have read that the S-100 Tarbell 2022 disk controller card was for IBM style soft sectored disks and and that it had Western Digital 1791/1793 controller IC's.

Does this mean that the the 2022 controller card (and running CP/M) would be expected to also work with a typical 5.25" IBM style floppy drive unit too ?

RichCini
October 17th, 2018, 04:25 AM
That card has a single 50-pin floppy connector which is for 8" drives. You could theoretically make an adapter for it to connect to 5.25" drives. You would likely have to modify any CBIOS to program the controller to use the smaller geometry and different physical characteristics (track/sector count, gap length, etc.) and then the corresponding DCB so that the CP/M geometry is correct.

On my IMSAI, I use a CompuPro card (which also has a 50-pin connector) connected to modified IBM 1.2MB floppy drives to emulate 8" DSDD floppies. On my Gazelle, I use the Tarbell 2022 connected to two Shugart 851 8" DSDD drives.

exidyboy
October 17th, 2018, 04:57 AM
I have read that the S-100 Tarbell 2022 disk controller card was for IBM style soft sectored disks and and that it had Western Digital 1791/1793 controller IC's.

Does this mean that the the 2022 controller card (and running CP/M) would be expected to also work with a typical 5.25" IBM style floppy drive unit too ?
According the Sorcerer Computer Users Australia (SCUA) newsletter December 1986 the Mitsubishi 4854-1 drive mimics an 8 inch 77 track drive (and only that kind of drive). The later model (without the dash one suffix?) can mimic both an 8 inch drive and a DSDD 80 track 300rpm drive.
So if you're not in the mood to create a custom CBIOS that might be an option.

Hugo Holden
October 18th, 2018, 01:20 PM
Thank you for those replies.