The CD drive on my Winbook Si has always been balky.  Late this week I 
received the upgrade to DeLorme's Street Atlas and installed it.  While I was 
playing around, the CD really sounded sick - three attempts to spin up, 
drive-use light on, nothing happening.

Sure enough, yesterday I tried to boot to the SuSE Linux install disk, and got 
the same symptom.  Drive must be dead.

So what do I do for mapping now?  Linux to the rescue:

dd if=/dev/hdc of=/usr/images/sa04data.iso

mkdir /mnt/iso/sa04data

Add the following to /etc/fstab:

/usr/images/sa04data.iso /mnt/iso/sa04data iso9660 ro,loop,auto,unhide

Add the following to /etc/samba/smb.conf:

[sa04data]
	path = /mnt/iso/sa04data
        guest ok = Yes

On the laptop, browse Network Neighborhood to the Linux box and map sa04data 
to next available drive.

Open Street Atlas, and when prompted for the disk, choose "browse" and point 
it at "E:" (the mapped drive).

Even over the wireless link to the laptop StreetAtlas runs better than it did 
from the local CD.

This technique won't quite work with my Garmin software, because it must run 
the data CD from the same drive from which the installation was run.  To get 
around this, I can re-install from a mapped image, but I think I'll just 
reassign the CD's drive letter and see if that does it.