Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!husc6!m2c!wpi!dseah
From: dseah@wpi.wpi.edu (David I Seah)
Newsgroups: comp.sys.apple
Subject: Re: Slot Assignments
Keywords: Slots, Booting
Message-ID: <3309@wpi.wpi.edu>
Date: 19 Jul 89 19:47:26 GMT
References: <447ed450.f759@gtephx.UUCP> <33278@apple.Apple.COM>
Reply-To: dseah@wpi.wpi.edu (David I Seah)
Distribution: na
Organization: Worcester Polytechnic Institute, Worcester, MA. USA
Lines: 26

Some other feller writes:
>> [...] since it never makes sense to boot off of a printer,
>>you put that down in a low slot position, like #1.  Since, it makes sense to
>>boot off of a disk, you put that in a high slot position.

Dave Lyons reponds:
>Except that the system is smart enough to realize when a card is not a bootable
>device--it looks at $Cn01, $Cn03, and $Cn05 for the values $20, $00, $03 to
>identify it as bootable.  (I think the ROMs *before* the enhanced IIe also
>looked at $Cn07, but I'd have to look it up.)

It might be fun to take an old Grappler or old unused interface card with a
removable EPROM and reprogram it for some fun.  As long as the boot device
signature bytes are intact, one could probably have the reprogrammed card do
something interesting like print "SWOOSH" or make a rude noise or put up a
little icon of some kind on the screen identifying the computer as "MINE!"
Afterwards, the firmware could get back control and continue scanning down the
slots.  Sound feasible?

I've heard that the Transwarp GS board puts up a graphics screen when you
powerup.  If this is true, how does the Transwarp get control?  Does it
immediately pull a non maskable interrupt and grab the buses, then control the
Apple in all its entirety?  

Dave Seah | O M N I D Y N E  S Y S T E M S - M |   Internet: dseah@wpi.wpi.edu 
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