On Thu, Feb 03, 2000 at 02:03:24PM -0700, John Starkey wrote:
> Mike Werner wrote:
> > On Thu, Feb 03, 2000 at 12:26:20AM -0700, John Starkey wrote:
> > If you've got an Ethernet device showing up as /dev/ttyS0 either there is
> > something badly wrong or this a device I've never heard of.. Ehternet
> > devices should show up as /dev/ethx
>
> I'm wrong, I think. I do know that I'm thoroughly confused now. Based on what I
>thought I knew.
Oh, don't feel too bad. When digging into hardware without already being
somewhat familiar with the hardware it is not too difficult to get lost.
> > Does setserial *actually* report eth0 and ppp0? Or are you "translating"
> > the output into what you think each ttySx is? If the latter, please tell us
> > *exactly* what setserial *actually* says. And have you verified that
> > /dev/mouse is linked to a /dev/ttySx instead of /dev/psaux? The ppp0 should
> > be your modem - the mouse will be the other serial port.
>
> /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
> /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3
>
> The other two are unknown.
>
> That explains why my eth0 shows up as 0x0300 but doesn't coincide with setserial's
>output. (it
> doesn't show up with setserial).
>
> What makes a serial device a serial device?? I understand serial and parallel but I
>think this
> is redefining things.
Uhhh ... that's kinda difficult to define. Technically a device can get
classified as either serial or parallel depending on how it talks to the
outside world. If data travels one bit at a time down a single common wire
it is a serial device. If multiple bits can travel down a set of wires at
the same time, then it's a parallel device. That's paring it all down to
the absolute basics - there's really a lot more to it then that. But
generally the designation of "serial" or "parallel" refers to the data
transfer between the device and the computer.
If I try and go much further with this definition I'll probably make a
complete mess of it. Is there anyone else here that can take a stab at
laying this out? It's one of those things that I pretty much know but
can't really define to someone else.
> > I think I might see a possible source of confusion here - try and follow
> > me here. You have an internal modem, right? And your Ethernet card is
> > plugged into the slot right next to it? Therefore eth0 and ppp0 are the
> > two serial devices? If that's not right, ignore the rest of this section.
> > If that's what happened - the physical location of a card rarely has any
> > influence on what port number it is. The modem (ppp0) will show up as a
> > serial device because it has one of those UART chips I mentioned - modems
> > are a serial device. But just because the modem is plugged into an ISA
> > slot does not mean that the card plugged into the ISA slot next to it will
> > *also* be a serial device. In fact that is rarely the case for a "regular"
> > home system.
>
> You hit the nail on the head here. I was assuming that the slots corresponded to the
>setserial
> entries. Thanks. This clears things up. And explains a lot of my previous confusion.
>
> If it has a UART it is a serial device??? So is there any other standard component
>that can have
> a UART. I don't have anything else on this system. A couple HDs, eth0, ppp0,
>monitor, floppy,
> tape, cdrom. If not then one of those setserial entries is my mouse right???
To put it *very* basically, yes. A serial device will have a UART or
be able to make the system *think* it has one. Still putting it *very*
basically serial devices are things like pointing devices and modems.
Pointing devices also come in PS/2 varieties, but as you've seen those
be plugged into a serial port via an adaptor. As I understand it the PS/2
protocol is similar to the serial protocol, which is why you can use that
adaptor.
And if what you listed is all there is to your system, then your mouse
will be either ttyS0 or ttyS1. The other * should* be your modem.
--
Mike Werner KA8YSD | "Where do you want to go today?"
ICQ# 12934898 | "As far from Redmond as possible!"
'91 GS500E |
Morgantown WV | Only dead fish go with the flow.
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