jesup@pawl22.pawl.rpi.edu (Randell E. Jesup) (04/17/88)
In article <1822@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes: >I hope that Commodore isn't going to screw something up that even IBM >got right. Look at the IBM AT bus. It's basically the XT bus with some >extra lines. > >Look at the Zorro-2 bus. It's got room to put those extra lines in. They'd >have to be left out of one of the bridge slots (you are going to have bridge >slots in the 3000, aren't you?), but the other bridge slot and the Zorro-2 >slots could have a secondary slot just like that ol' AT's. This has been EXTENSIVELY discussed on Bix lately. Remember, IBM just added lines, then sped the bus up until things started to fail. That isn't a very good option. For good 68030 performance, we need both a wider bus AND a much higher transfer rate. The current Zorro bus is merely the pinouts of the 68000 plus a few signals. It might be possible to share most of lines from Zorro-II by having a seperate AS for the extra lines, that signals use of the 32-bit bus at higher speeds. The Z2 cards should ignore everything if there is no AS. You could allocate the bottom 16Meg to Zorro-II, and the rest to Zorro-III. It would be good to also use a better protocol (less cycles/xfer) on the Zorro-III side. For REAL '030 performance, you might also want a seperate high-speed memory bus (1 or 2 slots), or put space for LOTS of memory on the motherboard. // Randell Jesup Lunge Software Development // Dedicated Amiga Programmer 13 Frear Ave, Troy, NY 12180 \\// beowulf!lunge!jesup@steinmetz.UUCP (518) 272-2942 \/ (uunet!steinmetz!beowulf!lunge!jesup) BIX: rjesup (-: The Few, The Proud, The Architects of the RPM40 40MIPS CMOS Micro :-)