[KLUG Members] Re: CD Burning, a Question or Two

[Bryan J. Smith]

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On Fri, 2002-12-20 at 01:45, Andrew Thompson wrote:
> but when I tried them in my new laptop's reader, it doesn't seem to
> even be able to recognize them!

Dyed CD-R media is not as 100% compatible as "stamped" CD-ROM media.=20
There can also be issues with recording at high rates and readability in
various, older drives.

Magneto-Optical CD-RW is even less compatible and reliable.  It has very
high error rates (typically 10^9) that can occur during the initial
write, let alone only has a limited lifespan (3-5 years) and number of
rewrites (~1,000).

> I was also curious about this: I thought I'd heard/read somewhere that
> ISO images on the hard drive could somehow be mounted or otherwise set
> up to be read and used as though they'd been burned to CD.

Yes.  Linux can read _any_ filesystem "image," be it Ext2/3, ReiserFS,
XFS, JFS, VFAT, ISO9660, UDF, etc... via the "loopback" device.

E.g.,:
   mount -t iso9660 -o loop=3D/dev/loop0 myimage.iso /mnt/myimage

You only need to pass the "loop" option and use an available loopback
device (e.g., "/dev/loop0").

You can even mount them "read/write" so they can be modified.  This is a
very powerful option for floppy and disk images, without having to have
a real floppy or disk.

Unfortunately, you can't modify ISO9660 images mounted on a loopback --
the format doesn't support doing such (long story).  But you _can_ do so
with UDF images, which is the optical filesystem format that supersedes
ISO9660 (although some older Windows versions don't come with UDF
support -- see Roxio.COM for free, UDF read-only support).

CD-RW and DVD-RAM/-RW/+RW "packet writing" (aka "random access"
"rewrite" -- e.g., Roxio DirectCD) uses UDF.

--=20
Bryan J. Smith, E.I. (BSECE)       Contact Info:  http://thebs.org
[ http://thebs.org/files/resume/BryanJonSmith_certifications.pdf ]
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