Tony Mantler wrote:
>At 7:41 PM -0500 9/3/2000, Peter wrote:
>[...]
>>Maybe I should clarify, I meant to have bootblocks so that one doesn't need
>>any MacOS partition at all. Ie only a few blocks in the beginning of the
>>drive that tells the Mac/m68k how to boot NetBSD.
>
>I toyed with this idea a while last time I was hacking at the Penguin
>Linux/Mac68k booter, but inevitably I determined that it wasn't really
>possible.
>
>
>First off, there's the interesting challenge that the state that the mac is
>in before MacOS gets loaded off the disk is hideously buggy and entirely
>undocumented.

What about debug the already existing code. Not necessarly by disassembling the
code but rather run the ROM/MacOS in an emulator. And log all I/O access.
I have done this with a scanner software for win3.11 once.
(to make a *bsd driver)

>Secondly, and most importantly, is NuBus. Right now the Penguin booter (and
>I assume the BSD booter does the same thing) relies on there being some
>sort of MacOS around in a relativley non-buggy state to be able to turn off
>all the NuBus cards in the system to prevent the slot interrupts from
>locking up hard and irrecoverably. Until such an unlikely time where
>there's drivers implemented for each and every last NuBus card in the known
>universe, the only way to have a snowball's chance in hell of booting on a
>randomly-equipped mac is to do so from MacOS.

Well one could rely on that the there are not so many cards used. Ie if you
use an unsupported card, it won't boot.
Anyway, when MacOS (ROM's) is booting it must have some way of turning of those
interrrupts. So I guess the answers to all this can be found in those ROM's.

Btw, anyone knows what type those MAC ROM are .. ?, ie what EPROM compability
they have.

>If you don't like it, go timetravel back to before 1987 and kick Jean Louis
>Gasee's butt for implementing NuBus in such a retarded way. :)

Oh.. I already sent my T2 :-)

Isn't NuBus quite more clever than ISA/MCA anyway ?, maybe even better than
PCI?

>
>Cheers - Tony 'Nicoya' Mantler :)

       /Peter