My understanding was that the second cartridge slot was not a very well thought out thing. I think there was one cartridge made for it (some debugging tool?) T

My understanding was that the second cartridge slot was not a very well thought out thing. I think there was one cartridge made for it (some debugging tool?) That port cost a lot of money per unit; Atari's early efforts were not very well cost reduced. If they'd been more aggressive about cost reductions (and improving I/O speeds) they might have done much better in the market against Commodore. Instead we got more unclear hardware directions (the 1200XL's "Help" key was a prime example of the hardware group just not caring about or talking to the software folks), even more expensive machines, and a bunch of work being done by outside contractors instead of inside staff because it was easier to build empires that way. The 7200 game machine (developed by General Computer Corporation in Cambridge, IIRC) was a surprise to most of us, for instance, and not a good one.