I'd like to know if Realteck 8139 networks cards work perfectly on mandrake 9.1? Does the driver already in? Do they immediately detect and ready to work?

Thanks.

As far as I know - I have 3 of these beasties - yes to everything.

These cards are a favorite because of the low cost and the fact that they just work and have just worked for a long, long, long time. I recommend them for most all client machines without a builtin nic (I've got an Intel Gigabit Pro XL server card in my personal one though). The only real downsides I've seen with Realtek are a slightly higher CPU usage, but a client can easily saturate that link without taking a significant hit (a server with 4 of these might be a different story, not sure). Also, if you need to handle many devices, I don't think you can specify which realtek card is which eth interface, so often card types are mismatched intentionally for things like routers so it's easy to tell interfaces apart even if cards have to be swapped between physical slots.

If the card was in your PC when you installed Linux it is probably already detected and running. If you installed the card afterwards you will have to go through the run around to get it configured and running at boot.
I have seen something about a version (8139 C?) being problematic though I don't know for sure.

Realtek 8139, is the low cost network card and the driver already include in almost distribution of linux.
It is the perfect card, i used it by my self in every computer in my company both linux and windows.