The Atari Wiki still isn't working, but I found some info in its source, which is readable (minus the images). There's also a Discovery cartridge owner's thread in this forum and I found some pictures and info here as well.
But I have a couple of questions I didn't see answered there...
1) Mine is the basic version (option 0) but with the extra cartridge option (the previous owner had done a nasty soldering job of adding a cartridge socket in the "J1" location. Obviously I'll have to check each connection, but I'm wondering: is this a cartridge "through" port? I'm a little confused because the Wiki article says:
HAPPY COMPUTERS has tested and found that the MAGIC SAC and DESKCART and SPECTRE 128 will operate as a second cartridge with OPTION 6.
- jack for plugging in a second cartridge
- 2nd cartridge enable switch
Many other cartridges may work with option 6 that do not work with options 3 or 4. We do not guarantee that any cartridge will work as a second cartridge. Some L shaped cartridges may not even fit as a second cartridge. The 2nd cartridge switch allows the user to select whether the 2nd cartridge or the DISCOVERY CARTRIDGE is enabled.
I always assumed it was just an ordinary "pass through" type cartridge connector, but does the above indicate that some cartridges/dongles might have address conflicts or other issues in conjuction with the Discovery cart?
2) There's a magazine ad for the Discovery cartridge posted here where it says that "the Discovery cartridge can be used with high density 3.5" floppy drives (available from other suppliers". Are they referring to an external HD drive which plugs into the additional floppy connector (the "J3" connector on the Discovery PCB, next to the one which goes to the Atari ST rear floppy port via a cable)? But where does the HD detect signal go when all the 14 pins are already used?
3) Has anyone here upgraded a Discovery cartridge board to add/upgrade to other options?
Like I said, mine is an "option 0" with an added cartridge port done by a previous owner. The abovementioned magazine ad says that "A technically inclined user can add their own options" which I'm not sure means to upgrade from a basic (option 0) Discovery cartridge to an option 1, 2, 3, 4, 5, 6 or 7 type unit, or if they mean that those with the right knowledge can modifiy it to do other things. In any case the schematics which have generously been made available shows the components and values, so I assume I can just add whatever additional option I need myself. Has anyone tried that?
I'm not interested in the Mac emulation (I'm writing this on a Mac and besides, the ST was way ahead of the Mac's features at that time, which is what the emulation is all about), but is the clock worth getting into, or are newer options better?
I can't see myself getting additional floppy drives, so those options might not be of any use either (it's been a while since I backed up anything with my Discovery cartridge but I seem to recall that I made floppy disk image files of them, stored on my hard drive, using the single built-in standard 720K STe floppy drive.
So what's left? The ROM sockets: are they just for the Mac emulator or can they be put to other uses of interest today?