"Len" wrote in message
...
Eric,

Glad you're still here... :-)

- 6 serial ports is a little tough to do with current PC platforms,
most users don't use them (although we all know that we do!). Not
impossible by any means though.
Of course there are multiplexers but I'd like to avoid added
complexity.

But added safety.

Larry mentioned another type of port for nmea. Can't these
be used?

Larry probably mentioned my multiplexers too :-)

I lack real understanding here. All I know I want to connect
multiple nmea talkers like gps, wind, depth, compass, ais, and I want
to let my nav prog talk to my autopilot.

And if your nav program or the computer goes down, you have nothing. With a
multiplexer, you can still feed the GPS data to the autopilot, because for
instance the ones that I produce, automatically fall back to a pass-through
mode where the GPS data directly goes to the autopilot when the connected
computer does not send any data for more than 10 seconds.

Talking of usb, I find this tech somewhat disappointing regarding
power supply. When I want to connect my usb-stick wifi-antenna the
show stops when I use a cable of 3 meters. XP says tehere something
wrong with the power supply.

That is because USB can feed only 500mA to a device. Wifi uses a lot of
power, so I'm not surprised that with 3m of cable, the voltgage drop is too
high.

- Also, Len, why an external hard drive? Do you mean an extra external
drive with one built in? This gives me the idea of modularizing as
much as possible. We could get this size down really small if
everything is an add-on (Optical drive, USB hub, storage drives,
etc...).
What I meant was it should be very simple to deal with a hdu-crash,
the biggest risk remaining when the pc is solid state. In my thoughts
I only have external hdu's and would keep say two external hdu's
"synchronized" so when one fails I have a near 100% backup including
OS and installed software I only have to connect my other unit: up and
running again in a minute.

It would be better in this case, to install XP Embedded, which can run from
a CF card without wearing out the limited write cycles of a CF card. The
card can be used write-protected so a crash can NEVER distroy your OS
installation. Put the nav software on the same card and load the charts from
a harddisk or SB stick, which you can easily upgrade. You can even install a
second XP on the harddisk, use this for entertainment while using the CF
installation for navigation only.

Meindert