I've happily used a 40GB Seagate ATA/33 disk in a 630 before. It's a bit of a waste if you run anything earlier than OS 8.1 on it mind you.
The key issue is *partitions* are limited to 2GB in early OS versions, I think they went up to 4GB at 7.6 or 7.6 (can't remember which) and at 8.1/HFS+ they went up to something silly. The physical capacity of the *disk* is not limited by these factors so much as you can have many 2GB partitions on a larger disk (I used to run 18GB disks in my 840av in 7.1 with 9 partitions each
). I think there is an upper limit on the number of partitions classic Mac OS can handle, but it's something bigger then you'd ever fit on your desktop I'd guess. I'd probably shoot for a 8GB or 16GB at most. Anything larger is gonna be wasted on a 68k era machine, even with FAT binaries the stuff was way smaller than anything on OS X these days.
The key issue is *partitions* are limited to 2GB in early OS versions, I think they went up to 4GB at 7.6 or 7.6 (can't remember which) and at 8.1/HFS+ they went up to something silly. The physical capacity of the *disk* is not limited by these factors so much as you can have many 2GB partitions on a larger disk (I used to run 18GB disks in my 840av in 7.1 with 9 partitions each
). I think there is an upper limit on the number of partitions classic Mac OS can handle, but it's something bigger then you'd ever fit on your desktop I'd guess. I'd probably shoot for a 8GB or 16GB at most. Anything larger is gonna be wasted on a 68k era machine, even with FAT binaries the stuff was way smaller than anything on OS X these days.