[RndTbl] command line question, cat and dd

I'm trying to write the file eb-5.0.7-via-rhine.lzdsk to a floppy diskette in /dev/fd0. When I did the following command: cat /home/ed/eb-5.0.7-via-rhine.lzdsk /dev/fd0 the screen filled with zeros and wierd characters and stayed that way after the command supposedly had finished writting the file to the floppy. I had to boot <Ctrl> <Alt> <Delete> since the keyboard was useless. No harm done. Everything seems OK after the boot. Using another floppy, I tried: dd if=/home/ed/eb-5.0.7-via-rhine.lzdsk of=/dev/fd0 obs=18k No problems with dd. The copy seemed to work quicker. My question is, are the two commands, dd and cat, equivalent for writting data to a floppy? And why did cat screw up my keyboard?