Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!oliveb!sun!pepper!cmcmanis From: cmcmanis%pepper@Sun.COM (Chuck McManis) Newsgroups: comp.sys.amiga Subject: Re: Studebakers Message-ID: <56647@sun.uucp> Date: 15 Jun 88 18:02:41 GMT References: <4400@gryphon.CTS.COM> <56089@sun.uucp> <1326@sbcs.sunysb.edu> Sender: news@sun.uucp Reply-To: cmcmanis@sun.UUCP (Chuck McManis) Organization: Sun Microsystems, Mountain View Lines: 72 Ok, Rick Spanbauer gave some well reasoned responses to my "dumb" bridge card posting which I agree with, however, I think I can be a bit clearer about this and maybe we can see the product opportunities. First let me describe the "dumb" bridge board which I would like to interest some hardware manufacturer in making, it looks like this : This card sits in a 'bridge' slot connecting the Amiga and PC/AT buses. On board it contains autoconfig logic for four (4) "PICs" and one memory "PIC". The manufacturer ID of those PICs are controlled by dipswitches on the board. (You'll see why in a minute). There is also some bus logic to convert x86 type waitstates to 68000 type waitstates and to optionally swap bytes on a 16 bit read. The dedicated memory PIC area has a dipswitch that indicates in sizes of 512K bytes, how much memory is on the AT bus. This memory is assumed to start at address 100000H on the AT side (1 Meg) and extend contiguously upward. Any PC/AT extended memory card could be plugged into the AT side and used at 16 bit Amiga memory. When suggesting to AT owners that they should upgrade to an Amiga 2000 this would let them hang on to their now priceless memory boards. The four 'private' PIC area would allow for the specification of a unique manufacturer ID. This would be given out by Commodore as they are today. When installing an AT peripheral into the 2000, one would install the board, set the Manufacturer ID on one of the custom PIC switches and then put the driver in the Amiga 2000 expansion drawer. On reboot, the new device would be available. The PIC circuit on this bridge board would map the 64K PC I/O space into one of the Amiga's 64K I/O slots. It would still be impossible to make an autobooting hard disk that sat on the PC side (unless there were autoboot roms on the dumb bridge board for just that purpose). The advantages to this scheme are a) It's cheap, this is easily a two layer board with at most 30 components. b) It opens up the AT bus to Amiga programs in their native environment, no steep learning curve, no special coding. c) It makes it possible to take advantage of AT frame buffers *now* with equivalent performance. There is no reason that a 7.5Mhz 68000 couldn't update a Targa board as fast as a 6 Mhz AT, or at nearly the same spead as an 8Mhz AT. d) It allows vendors of PC compatible boards (who are a looking at the MicroChannel and wondering how to milk a few more $$ out of their AT Bus designs) to offer their boards into an entirely new market to them. e) It allows programmers like those on this net, to get their hands on specialized hardware like IEEE-488 bus adapters without having to invest in building the hardware. I'm not talking about pro developers, I'm talking about someone who wants both a MIDI interface and a serial port and has enough brains to write a driver for the Voyetra PC-Bus MIDI interface. We're talking free or at least shareware stuff here. They may even be able to sell it back to the manufacturer for a few bucks. So since Commodore hasn't done this, there appears to be a window of opportunity here. The nice thing for hardware manufacturers is that this board could be shipped with *NO SOFTWARE* that's right, once your hardware is done you can ship this puppy, unlike most other products for the Amiga. Of course you will want to test it to make sure it works and thus will probably end up writing a driver or two for it. Make sure it can autoconfig some memory into the system, and maybe write a really simple driver for a parallel port or something. Anyway, I am astonished that no one has done this yet. (I would but can't seem to find the time, I've been thinking about it for a couple of weeks now.) --Chuck McManis uucp: {anywhere}!sun!cmcmanis BIX: cmcmanis ARPAnet: cmcmanis@sun.com These opinions are my own and no one elses, but you knew that didn't you.