kruger@16bits.dec.com (Bear with me) (04/15/88)
Craig Hubley (craig@unicus.com) writes that moving to 32 bits may introduce some incompatability. No. Except for exception processing, the 68020/68030 can behave identically to the 68000. The 16/32 bit bus is completely transparent. For that matter, if you're into low performance you can have an 8 bit bus. (Ain't that grand?) The problem that was stated previously still stands. Any board doing addressing on its own (presumably DMA) will not be accessing the high 16 bits of 32-bit memory. This CAN be solved, because the older boards are, of course, slower and therefore, an extra gate delay in there isn't going to affect anything. But you can't have 16/32 bit slots then, you'd have to dedicate a couple of 16 bit slots, which would demultiplex onto the high or lower order word of memory. This is all very well, but I'd rather if Commodore minimized hardware, maximized profits, and gave us all kinds of support. Quoting IBM & Taiwan Joe clones as a precedent for upwards compatability makes me sick -- after all, that's the major reason MS-DOS and IBM software in general is so poor -- everything sinks to the lowest common denominator. When I buy an A3000 (WHEN!) I would hope that vendors will support high- resolution graphics in games (thankfully not too hard on the Amiga), 32-bit peripherals, and hopefully, the enhancements to the 68000 instruction set. If everyone gets too focused on keeping what they've got, new stuff is neither as cheap, plentiful nor quick to come out. I'm realistic enough to know that most of this won't happen for a long time -- there will be so many A500's that all games will be written for them, so forget the '030 instructions, and any versions specifically geared for a big screen :-( But the more seriously the Amiga development world moves to 32 bits in a serious way, the better it will be. (my 2 cents) dov