[rescue] AT&T 3b1 Starlan software

[Scott Newell]

>> What happens if someone moves a card from one slot to another?  (I've
>> never messed with the Apple II, and I've always wondered how software
>> could figure out which interrupt lines and memory spaces to use when
>> cards got shuffled around.)
>
>Simple--the lines are hardwired to particular slots.  IIRC, moving a

Yes, that part I get.


>When you set up your software, it would ask you where some devices were.
>For example, floppy controllers typically lived in slot 6.  Some

OK, this is what I wanted to know.  If software assumes that the floppy is
always slot 6 and you move it, you're hosed, correct?  That's the big
drawback that I can see.  (And I realize it's only a problem for poorly
written code.)  Did they make allowances for cards that require more than
one interrupt line?


>Now, this sounds cumbersome in this age of plug-and-play, but it's a lot
>easier to look at the rear of a computer and say "Hm, the wire to the
>disk-thingie plugs into the slot next to the number 6" than remembering
>IRQ + DMA + Memory address like PCs made you do all the way into the mid
>90s, and more flexible than the PC way of "devices available at boot
>time -MUST- be at IRQ/DMA/Memory such-and-such".

Does each slot have X amount of memory space allocated to it?  Seems to me
the simple backplane has an advantage if you've got cards that require
almost no memory space, and some cards that require a large chunk.


Don't get me wrong--I've fought IRQ battles on peecees for years, so
location based interrupt lines are pretty attractive to me, but I'm curious
as to the tradeoffs.


newell