Thanks for your suggestion, Dieter and der Mouse.

I examined two serial cables(mmj <-> db9 and db9 <-> db9) I have with 
windows hyperterminal. I used the idea of der Mouse because I don't have 
any rs-232 LED display. All cables (and hyperterminal) work perfectly 
well. (I couldn't find my knoppix live cd, so I'm using hyperterminal). 
Echoing idea is quite effective I think(why I couldn't do that before 
you guys suggestion? I blame my lack of imagination!)

Now I'm going to try my floppy booting procedure this morning. Any 
suggestion, experience, and tips will be appreciated!

Thanks

Jong-won