If you have an iso file, want to access files in it without writing it to a CD or DVD, you can mount it.
For example, let's say you downloaded tinycore_3.6.iso to /home/tc/dl
Create a new directory in /home/tc/dl. Let's call it tmp.
Open the terminal and type
sudo su cd /home/tc/dl /bin/mount tinycore_3.6.iso tmp
sudo su cd /home/tc/dl busybox mount tinycore_3.6.iso tmp
An example of this is used in Update Tinycore.