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Boot CD

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9 replies

by it rookie

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.
Is it true that all cds are bootable? My reason being I burn a copy of windows from an original. However, when I try to boot from the copy it failed, but not from the original. Are there files missing maybe?

9 replies

by maelgwyn

All CDRs can be bootable, yes. However, it is
the same as a floppy disc that certain files are
required. There is some great resources on
www.bootdisk.com (no spaces), but see Barts
document on it (it is on the site), it is one of the
best.

Best of luck

Maelgwyn

by thechas

Actually, very few CDs are bootable.
Typically, only the last few versions of Windows, and some system utilities have been distributed on bootable CDs.

For a bootable CD to work, the motherboard needs to support booting from a CD, and, the CD drive needs to be in the BIOS boot sequence options before any other bootable drives.

You can create a bootable CD-R disk.

There are links to various techniques posted at www.bootdisk.com

This Tech Republic article

http://tinyurl.com/9mej
also has tips for creating a bootable CD.

Windows 2000 and Me were the first versions of Windows to ship on a bootable CD.
I am not aware of any bootable CD distributions of earlier versions of Windows.

To check if a particular CD may be bootable, look in the root folder of the CD.
At a minimum, there needs to be a file named command.com
If command.com is not in the root folder, the CD most likely will not boot up a PC.

As to your copied CD, how did you copy it?
You must use a copy and not just a CD recording program to maintain the bootable status of a disk.
In addition to the files, a flag needs to be set in the MBR to make it bootable.

This is similar to when you would copy a floppy. If you used a file manager, and simply copied the files, the new copy may not be bootable.
However, if you used the disk copy command, the new copy would be an exact duplicate of the original, and could be used as a boot disk.

Chas

by fred07

Both above are correct and true. I have also found that to fast a write speed or a particular brand of cdrw disks do not do a good job of copying. I also have a cdrw that copys well but does not read correctly. Same cd in the read only cd boots justfine. My cdrw reads original and boots fine just will not boot the copy it makes. Hope this helps.

by alpha-male

What makes a disc (CD, Floppy, HD) Bootable is the presence of the invisible system files. THese vary depending upon the OS, but if you do not include them, the disc will not boot.

This is why many people create ISO images...so you get a direct and exact copy of a disc, rather than just the visible files on it. Additionally, Nero and other burning software include directions on making a disc bootable. I was even able to create a nice bootable DOS CD which has been very convenient at times.
Good luck...

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