[Linux 文章收集] Linux creating CD-ROM ISO image

Source From Here 
Preface 
dd is a perfect tool for copy a file, converting and formatting according to the operands. It can create exact CD-ROM ISO image. his is useful for making backup as well as for hard drive installations require a working the use of ISO images. 

How do I use dd command to create an ISO image? 
1. Put CD into CDROM 
Do not mount CD. Verify if cd is mounted or not with mount command: 

# mount // Make sure CD is not mounted
/dev/mapper/VolGroup-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
...

If CD was mouted automatically unmout it with umount command: 

# umount /dev/cdrom
OR
# umount /mnt/cdrom

2. Use Command dd To Create ISO file 
Create CD-ROM ISO image with dd command: 

# dd if=/dev/cdrom of=/tmp/cdimg1.iso
// if=/dev/cdrom: Read from /dev/cdrom (raw format)
// of=/tmp/cdimg1.iso: write to FILE cdimg1.iso i.e. create an ISO image

Now you can use cdimg1.iso for hard disk installation or as a backup copy of CD. Please note that dd command is standard UNIX command and you should able to create backup/iso image under any UNIX like operating system. 

Supplement 
* Create an ISO Image from a source CD or DVD under Linux 
* To verify the ISO images use an md5sum program 
* Extracting particular file from Linux ISO (CD image) file after installation 
* How do I write CD at Debain Linux command prompt 
* Splits directory into multiple with equal size for ISO burning purpose