Summary: 4-port cards

[Dave McLane]

gemini at geminix.in-berlin.de (Uwe Doering) writes:

> If you feel that the UARTs on your main board consume too much CPU
> time, then they are no NS16550A chips. At least I don't know of
> any NS16550A chips that are integrated with other functions, so
> I think that there are rather NS16450 or 8250 chips on the main
> board. But then I don't quite understand how this led you to the
> assumption that the `AF' type has another functionallity than the
> `A' type of the NS16550.

Well, actually, I wasn't talking about the difference between the
'A' and 'AF' chips, just the fact that even though some chip is
"said" to have FIFOs on it doesn't mean that driver will recognize
them as such.

FAS puts up a display when the system boots showing what kind of
chips it has recognized and you can run XU under DOS to get a
reading.  When my Dell 333D boots ISC UNIX with a 4 port Decision
card in it FAS shows FFFF for the Decision ports and ** for the 2
ports that are integrated into one chip on the Dell motherboard.
Another board I had in the machine had UM82C550 chips on it which
were *said* to be "the same as" 16550s, but FAS/XU didn't recognize
them as having FIFOs.

The point I'm trying to make is that chip only has functioning
FIFOs on it when the driver recognizes them, not when somebody
"says" it has FIDOs....

--Dave