> I favor big endian for the mips project for two reasons:
>
> 1. Binary compatibility hacks with other Mips systems will be
> impossible or incredibly difficult otherwise.
>
> 2. It would be a very good idea to leverege off the architectural independence
> work of the 68000 port. I am not talking about a port of their port,
> rather
> that we work in tandem with them in building a portable linux source tree.
> And the neat thing is, they're allready dealing with the little-big-endian
> issue.
>
> 3. I like big-endian. (Not a reason. A bias.)
I totally agree !
> The problem I see is with interfacing with the ISA bus. The software will
> have to know how to
> deal with the endianness, or there will have to be a hardware swap.
> Does the nifty bus controller already deal with that?
> How much more difficult would this make writing device drivers?
What ISA-bus-cards do we need ? Perhaps some more serial lines,
a fax-modem or the like. Most of them are 8-bit, so where is the
byte-swapping problem ?
> If SCSI, ethernet and video are on the motherboard, I think that we don't
> need to invent
> another super-nifty multi-cool expansion slot system.
Right.
> a) that is hard
> b) we probably wouldn't get it right the first time
> c) most of the fast stuff is already on the motherboard
> I agree that an ISA bus would be neat and allow us to put lots of
> clone cards in the system, but I could live even without this.
Right too.
> However, I feel that we should run every line going to the cpu also
> to some sort of connector. Just one. A bunch of other signals can
> go to/come from this slot, but the important thing is to allow
> someone else, later, to put a daughter card there that perhaps
> can do the nifty bus stuff, or whatever.
That might lead us into heavy-duty timing problems. I would not
do that since nobody knows what kind of daughterboards we might need.
> Perhaps someone would like to make an AXP daughtercard. Or a 486 card to
> allow
> running of Linux binaries. Make it simple. Don't worry about
> how others might use it. And the great thing is, it is just
> the cost of a (perhaps very big) connector. Cheap. Which I
> appreciate.
Too much overhead. And big connectors aren't cheap !
We would have to guarantee timings, signal delays, driver fan outs
and so on, or third-party add-on cards may run on one one board
but not on others.
What do we want to have ? A low-cost/high-speed workstation or a
multi-cpu/multi-architecture dinosaur ?
Bye,
Andy
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