
Originally Posted by
SlimBiggins
I am in the process of backing up a bunch of CDs. I have been using the following command to do so:
Code:
dd if=/dev/cdrom of=/media/sdb/filename.iso
I've noticed that in most of the .ISO images created this way (nearly all), when mounted using Archive Mounter or when viewed using Archive Manager, every file has
;1 at the end of the filename after the appropriate file extension.
1. What is the purpose of this
;1 extension?
2. Is there an argument I can use to stop
dd from creating this extension?
I'm not familiar with Archive Mounter or Archive Manager, so I can't speak to what they're doing; however, the dd command you presented does not change the data you're copying. The ;1 extension is a file version number, which is an optional part of the ISO-9660 standard. See this wiki page, for instance; or search on "iso-9660 semicolon" for more information.
Linux ordinarily hides this file version number. You can change mount options to display them, though:
Code:
sudo mount -o map=off,norock,nojoliet /dev/sr0 /mnt
Change the device filename (/dev/sr0) and mount point (/mnt) as necessary or desired. Note that to display these version numbers, you must also ignore the Rock Ridge and Joliet extensions, which provide long filenames that do not include the version number. Thus, the filenames may not exactly match what you normally see, beyond the version number.
3. And is
dd the best for backing up CDs to an image file? (As far as reliability goes)
Assuming the original disc is readable, yes, dd will work fine. Mrhhug's concern about dd's speed isn't an issue for typical data CDs. The speed problem with dd only applies to hard disk partitions, which typically contain large chunks of unused disk space that dd will nonetheless dutifully copy, wasting time. Data CDs normally lack such big unused spaces, so you needn't be concerned with this issue when copying data CDs.
If the disc has errors on it, then you'd be better off using ddrescue or gddrescue (both are in the Ubuntu repositories). The dd program aborts when it encounters an error, resulting in a short file. The ddrescue program doesn't do this; instead, it leaves a gap in the file, which is likely to corrupt one file and leave the rest of the disc intact. The gddrescue program makes repeated attempts to read bad sectors, which is more likely to recover data even from damaged discs.
The problem is that I'm mounting the .ISO images as a virtual drive (instead of burning a copy of every disk I use), but the
;1 at the end of every file doesn't allow the files to be opened/executed with a double-click because nautilus does not recognize the type of file.
Try this:
Code:
sudo mount -o loop -t iso9660 imagefile.iso /mnt
Change imagefile.iso to your image file's filename and /mnt to your desired mount point. For some discs (particularly some DVDs), you may need to change iso9660 to something else -- typically udf, but sometimes hfs or hfsplus for discs that originated on Macs. This command should mount the image without displaying the ISO-9660 version number, just as if you'd mounted the disc normally. It sounds like the Archive Mounter program you're using does things strangely.
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