Don't know about floppies, but hd's have an interleave issue between some early Mac models. It usually makes them slow though. Try asking this on m68kla.org -- alex ----- Original Message ----- From: Josh Dersch <derschjo at gmail.com> To: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Sent: Sat, 25 Jan 2014 00:00:54 -0700 (MST) Subject: 128K Mac oddness... So it being the 30th anniversary of the Mac and all, I thought I'd play with my 128K Macintosh a bit. I've had it running beforeI, but never got it running anything interesting, so I thought I'd start with a few small games... and there, the trouble began. In a nutshell: I have a few 400K boot disks that I wrote years back (and they're still fine), these contain System 2.0 and System 3.2. All well and good -- I can boot and everything's grand (though a bit boring.) Likewise, I can format other 400K disks in either the external drive or the internal drive, and read/write from/to them without problems. UNTIL... I take one of the 400K disks I've formatted on the 128K Mac and attempt to copy some games from my Mac 512Ke to the disk. The 512Ke is happy to read/write the disk (using the same external drive I used with the 128K Mac) and everything's marvelous. But afterwards, when Finder on the 128K Mac attempts to open the disk, it bombs out with an address error ("Sorry, a system error occurred. ID = 02") and I'm forced to reboot. At this point, I've tried: - Using the internal rather than the external drive to read the disk (suspecting some manner of alignment issue with one or more of the drives) - Several different floppies (all DD, not HD, before you ask :)) - Formatting the floppy on the 512K Mac. - Copying files to a system disk, rather than a blank disk and then booting from said system disk - Booting the 512K Mac with various different System versions (3.2, 6.0.3) and doing the copy from there. - Both System 2.0 and System 3.2 All with the same results -- once the 512K Mac has modified the disk, the 128K Mac chokes on it (it will still *boot* from a modified System disk, but is unable to open it in the Finder without crashing.) At this point I'm stumped. I suppose it's possible my 128K Mac has a fault of some sort (a bit difficult to diagnose given my lack of ability to run a diagnostic...) but it seems to work fine otherwise. Is there some incompatibility between the filesystem portions of the toolbox ROMs in the 128K vs. the 512Ke that could cause problems here? My early-Macintosh-System-Fu is rather weak (I haven't used anything prior to System 6.X all that much) so perhaps I'm missing something obvious here... Thanks for any tips... - Josh