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SubjectRe: serial ports

> I wish people would *READ* the whole message before sending flames out.

I wish people wouldn't yell "FLAME!" everytime somebody disagrees
with them.

> If you had read the rest of the message, you will see that I addressed
> multiport serial cards like the AST Fourport and the Bocaboard BB-1004,
> BB-1008, and BB-2016. However, I stand by my original statement ---

I did read and understand the entire message. For that matter, the
entire thread. Did you treat my message with the same courtesy?

I was refering to 2 and 4 port cards like the generic ones you
can pick up at most computer parts desks. I also carefully chose
my words so that what I wrote could be applied to _ANY_ brand.

> The reason why you can're share COM1 and COM3 is electrical.

Here you go again. You are wrong because you are not telling the
whole story.

I'll repeat myself:
You _CAN_ share any interrupt. It takes extra hardware. A board
that supports this _CAN_ share IRQ4 between COM1 and COM3.
_BUT_ not all boards have this capability.

I have and have used several 2 port multi-uart boards that _properly_
support COM1 & COM3 interrupt sharing. I've also used ones that didn't
support sharing.

I have and have used several 4 port multi-uart boards that _properly_
support COM1/COM3 & COM2/COM4 interrupt sharing. I've also used ones
that didn't support sharing.

The vast majority of the cards I am refering to are generic.
Some contain discrete uarts (8250, 1450, 16550, 16560), and others
contain _dual_ uart chips like the 16552. In fact, I just picked
up a pair of these the other day and have one one on the bench now.

I should mention that I started out life as an Electrical Engineer,
and still have a reasonably equipped test bench (and I can borrow
what I don't have from a friend - heck, he even has a wave soldering
machine in his basement).

> This statement says nothing about multi-uart cards (which typically use
> different I/O ports and IRQ's than the COM1/2/3/4, to reduce the chances
> of port and interrupt conflicts). Multi-uart cards was addressed later
> in the *same* *email* *message*. My entire message was was all
> encompassing, if you had actually bothered to read it.
> Grumble.

You are wrong - that is _EXACTLY_ what I was refering to.

"Multi-uart" means "more than one uart". This is an important distinction,
especially with the flood of newer single uart cards with extra-high speed
uarts (for modems that support it), that are starting to appear now
(You are in touch with this I hope?). Also, some cards with a single
standard NS16650AFN uart are still available too.

Things with uarts that I've used:
- 1 port cards
- multi-port (2 to 8 port) cards
- motherboards (2 ports)
- multi-function cards (1, 2, or 4 ports).
Some models have discrete uarts, some don't. Some models support interrupt
sharing, some don't. THERE IS NO HARD AND FAST RULE!
This is what I stated in my last message (lines 20, 31-32).

Just because something is outside of your experience, doesn't mean
it doesn't exist. (I've never seen or used a DEC Alpha, but they exist.)
Standard 2 and 4 port multi-uart devices that share interrupts properly
are very familiar to me. Perhaps not to you, but I can assure you that
they do exist and can be quite common.

It is useless to grumble. That doesn't make you right, and it
certainly doesn't help prove your case. Please have a beer
and relax :-) life is too short to take so serious!

- --
Andrew E. Mileski
Linux Plug-and-Play Project Leader
PGP Public Keys & Signature are at

Version: 2.6.2


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