In 1985 (or so) I got a “WARP 20” internal SCSI hard drive for my original Mac 512k. Of course there are no internal expansion connectors at all on an original

In 1985 (or so) I got a “WARP 20” internal SCSI hard drive for my original Mac 512k. Of course there are no internal expansion connectors at all on an original Mac. Steve didn’t want the purity of the hermetically sealed machine to be sullied. This thing came with a custom-made tool to get the case open (a long-shafted Torx driver with a flat paddle welded to it to pry the case apart). Once there, you removed the ROM chips, placed them in a little daughterboard, and inserted that into the ROM sockets. That’s how they got access to the CPU bus. There was a SCSI controller and some address decoding on the board that attached to the drive over a ribbon cable. They wrote a custom driver to talk to the controller, and even gave out the source code. Fortunately Apple had just released the first version of HFS for the 800k floppy disks, so to the OS this looked like a giant (20MB) floppy.