Hello, As the last remains of my PET retrivals, I have a handful of dual floppy drives (3040 and 4040) in my basement. Up until today, I thought they were all broken and were ready to throw them away. However, I have just realized they're not broken - they are just stuck with Commodore DOS 1.X as opposed to the 2.X versions I am used to. Even the ones labelled 4040 have DOS 1 ROMs. Now that I have good faith I can put together at least two or three working floppy drives, I wonder if there is any way to upgrade them to a newer DOS version. My EPROM programmer can handle 2532 chips, so upgrading the ROM is not a problem, but I have noticed that a DOS 2.x floppy drive uses a different 6530 RIOT than a DOS 1. If I only upgrade ROM and keep the original RIOT, will it work at all? Is there any custom DOS 2 compatible version that could be made to run with a board otherwise equipped for DOS 1? Is there some known replacement circuit for 6530 chips? I see there exists BIN code from a DOS 2 chip, so I assume there is a way to program an "emulation" as well. I do realize it contains RAM, I/O and timers so not trivial. If nothing else, I will continue to assemble and test my drives to see how many I can get to work reliably, then see if anyone on the list has spare RIOTs and perhaps ROMs too to trade with me. Best regards -- Anders Carlsson Message was sent through the cbm-hackers mailing listReceived on 2010-07-30 21:00:07
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