Is it possible to make support for compressed images?
Why are many of the MDS images (of CDs) much bigger than 700MB (sometimes up to 900MB)
Compressed images?
Started by
radiv
, Oct 30 2005 07:08 AM
7 replies to this topic
#2
Charalambos
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Posted 30 October 2005 - 06:11 PM
The CD images often contain raw data( 2352 bytes per sector) and not only the user data( 2048 bytes per sector). They may also contain the subcode data( 96 bytes per sector) and they also contain information about the disk that the image was made from- data burning mode, sessions, tracks, type of data e.t.c. As for compressed images support I don't think that it is something easy to be done.
#3
seebs
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Posted 02 November 2005 - 07:44 PM
I don't know how easy it is. GameDrive has it. In principle, the technology needed to make compressed image has been known for decades. Data compression is known, and block-level compression is known. It would be some more work, but I would guess it would be rather worth it.
#4
aaron44126
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Posted 02 November 2005 - 11:23 PM
You can use NTFS's compression on your images and they still work fine — depending on the content of the image, this works better sometimes than others, but I have some that are made a couple hundred megabytes smaller just by doing this.
(If you didn't know about NTFS compression... From Explorer, Right-click, Properties, Advanced — you can do this for a whole folder as well.)
(If you didn't know about NTFS compression... From Explorer, Right-click, Properties, Advanced — you can do this for a whole folder as well.)
#5
radiv
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Posted 06 November 2005 - 08:03 PM
Didn't know that NTFS compression was useful for something 
Thanx a lot
Thanx a lot
#6
Jito463
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Posted 07 November 2005 - 05:11 PM
Semi-useful. I compressed about 106GB of my images with NTFS compression and only gained a meager 3GB. Wasn't really worth the 1.5 hours of waiting for my machine to compress them.
#7
Charalambos
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Posted 07 November 2005 - 05:40 PM
The data contained in the installation CDs of the programs are usually already fairly compressed( e.g. in the form of .cab files) so I think that any kind of compression can't really offer much in this case.
#8
MaLing
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Posted 08 November 2005 - 07:28 AM
From my personal opinion, there is considerable discrepancy between compression of disc images and .exe files.
The format of files in a hard disc drive is different from a disc. Therefore when we convert a file to a disc image, the 0s and 1s are rearranged to suit the physical construction of a disc. This rearrangement always tends to produce an image in bigger size.
If I were correct, then since the order of 0s and 1s was different, it might be a chance to compress the image. However, the compression would unlikely reduce the size of the image smaller than its original file size in the hard disc drive. As what Charalambos has mentioned, the files are already compressed by the programme producer.
The format of files in a hard disc drive is different from a disc. Therefore when we convert a file to a disc image, the 0s and 1s are rearranged to suit the physical construction of a disc. This rearrangement always tends to produce an image in bigger size.
If I were correct, then since the order of 0s and 1s was different, it might be a chance to compress the image. However, the compression would unlikely reduce the size of the image smaller than its original file size in the hard disc drive. As what Charalambos has mentioned, the files are already compressed by the programme producer.
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