How do you write dvds?

[Margaret Doll]

I have been trying to write dvds using cdrecord on RedHat systems,  
2.4.21-57.ELsmp and 2.6.9-78.ELsmp.

I use

mkisof -R -o  disk1.iso disk1

  cdrecord speed=4 dev=/dev/cdwriter:@ disk1.iso

The Vendor_info from cdrecord:  'HL-DT-ST'
Identification:  DVD+-RW GWA4164B

Using generic SCSI-3/mmc
Drvier flags:  MMC-3 SWABAUDIO BURNFREE

cmd finished after 0.001s timeout 40s
cdrecord:  No disk / Wrong disk!

I have tried  DVD-R by Memorex, imation DVD-R and HP dvd+R