[CentOS] Setting CDROM parms

My apologies in advance for asking such an elementary question.  I 
called myself searching the Installation Guide and Deployment Guide, 
with no success.
The situation is that I bought a Lite-On ATAPI iHAP122 that will not 
burn DVDs unless I use hdparm to turn dma off. I bought that drive 
because it was a rare beige drive.  Until I can find a decent DVD burner 
and/or get a Windows machine put together strictly for doing BIOS 
updates, running with dma disabled seems to be the best solution. 
(hdparm -d0 /dev/hdb )
So, my question is, where should I script the command without having to 
become root each time I wat to burn a DVD?

2.6.18-164.9.1.el5PAE #1 SMP Tue Dec 15 21:41:47 EST 2009 i686 athlon 
i386 GNU/Linux

This is how it always fails:

[rj at madeleine ~]$ growisofs -dvd-compat -Z 
/dev/hdb=/home/rj/KNOPPIX_V6.2DVD-2009-11-18-EN.iso
Executing 'builtin_dd if=/home/rj/KNOPPIX_V6.2DVD-2009-11-18-EN.iso 
of=/dev/hdb obs=32k seek=  0'
/dev/hdb: "Current Write Speed" is 16.4x1352KBps.
:-[ WRITE at LBA=30h failed with SK=4h/ASC=08h/ACQ=03h]: Input/output error
:-( write failed: Input/output error
/dev/hdb: flushing cache
/dev/hdb: updating RMA
/dev/hdb: closing disc
[rj at madeleine ~]$