Hello and thanks for you interest and replies,
I currently have no plans to add memory to the machine. What I really want to do is getting the mass storage on the cosmosEx going. My TOS About Info lists 1985, 86, 87, 88, and 89.
For software development, I will stick with emulation, and test-run the programs on the real machine.
Do you know any Atari specific literature on these machines that are useful to a software developer ? Either bare metal programming, or using TOS.
Cheers