[Coco] CoCo 'Extended ADOS 3'--How do I get this working?

[Al Hartman]

I am pretty sure that one of the computer tech guys in Australia has created an FD-503 replacement board.

-[ Al ]-
On 9/2/2017 8:17:13 AM, Francis Swygert <farna at att.net> wrote:
The biggest challenge with making DECB access larger floppies is that it must still be capable of reading smaller capacities also... or at least it used to be. For a custom configuration you can change it, but then wouldn't be able to access older floppies. You can put two different configurations in a disk controller and physically switch between the ROMs, but not "on the fly". You'd have to reboot after switching. That could be a reasonable alternative to most, just use the second configuration (for lower capacity drives) when copying disks. If that were the only function, several DECB commands could be eliminated to make room for the drive operations in the custom ROM.

The other challenge is the controller itself. 720K drives are the most the common controller will handle due to the chip used. I don't think there is a pin compatible controller chip that can be substituted that will handle 1.44M drives. A new controller compatible with the older formats (including SS35T) would need to be made first. If it could be done at a reasonable price that would be great, but with DriveWire and the CoCo SDC I'm not sure it is really necessary. A cheap, older PC clone running DriveWire can access a 1.44M drive easily and cheaply. Once the boot for the PC is straightened out it can even be run "headless" -- no keyboard or monitor -- though that might limit operations (I've never run DriveWire... I think it can be run headless though...) Frank Swygert
Fix-It-Frank Handyman Service
803-604-6548

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