Written by DrG the 8 Dec 09 at 09:50.

This idea will be beneficial especially for live CDs , systems with small disk space and virtual machines.

The basic idea behind executable compression -----------
There will be a switch in the header of the executable , system will look for this and decompress required parts of the file to memory . ( This will require kernel support . Another options are integrating a tiny decompresser inside the executable or using system's built in )
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The live CD is already compressed , but with LZMA . LZMA is inferior to other algorithms like that of FreeArc (combines multiple algorithms including lzma ) ( http://freearc.org )
See - ( http://www.maximumcompression.com/data/summary_mf2.php )
FreeArc is more efficient than lzma , both in compression ratio and decompression time .
Compressing squashfs of Live CD with these algorithms is a better idea for live Cds.(Such Live CDs will carry more applications – see below)

But compressing executables and libraries ( with or without other data files – which only plays a minor role in the boot process ,most of them, like jpg has already got good compression already ) will help to reduce the size of installation , say for small netbooks or embedded .Furthermore Most of the Linux newbies are from windows and most of of them will try Ubuntu from virtual machines or from wubi .They will allow only a fraction of space for the virtual hard disk . If the installation is smaller they will be more comfortable .

This idea will be beneficial especially for live CDs , systems with small disk space and virtual machines. The basic idea behind executable compression ----------- There will be a switch in the header of the executable , system will look for this and decompress required parts of the file to memory . ( This will require kernel support . Another options are integrating a tiny decompresser inside the executable or using system's built in ) # --------------------------- The live CD is already compressed , but with LZMA . LZMA is inferior to other algorithms like that of FreeArc (combines multiple algorithms including lzma ) ( http://freearc.org ) See - ( http://www.maximumcompression.com/data/summary_mf2.php ) FreeArc is more efficient than lzma , both in compression ratio and decompression time . Compressing squashfs of Live CD with these algorithms is a better idea for live Cds.(Such Live CDs will carry more applications – see below) But compressing executables and libraries ( with or without other data files – which only plays a minor role in the boot process ,most of them, like jpg has already got good compression already ) will help to reduce the size of installation , say for small netbooks or embedded .Furthermore Most of the Linux newbies are from windows and most of of them will try Ubuntu from virtual machines or from wubi .They will allow only a fraction of space for the virtual hard disk . If the installation is smaller they will be more comfortable . Slow disk read time is the major factor which slows down a live CD compared to hard disc. By better compression , the data to be read is much less . For most of the standard compression algorithms the time taken for decompression is very small ( compare to the existing lzma ). So the applications will be faster. Let system or user determine the option. As these algorithms are loss less they should be reversible to the original uncompressed version. Most of the laptops and PCs have lavish disk space with fast read time . For them the compression may be of no value. In this situation 1.Allow system automatically decompress and install the uncompressed version as per the PC configurations. 2.Allow user to choose. The amount of ram will not be an additional problem – The efficiency of the existing squashfs is lower. #---------------------------------------------------------- Tail... [[ compression of the executable 'gimp-2.6' size 4.1 MB (4341512 bytes) ( with aspire 4720z ) 1.lzma (with switch -9) > 6 seconds > 1.2 MB (1229132 bytes) 2.arc (with switch -m9 ) > 5 seconds > 983.5 KB (1007090 bytes) ( 20 % reduction in size , 17 % in time compared to lzma ) . If we apply the same statitics to squashfs of live cd (may vary ), 140 MB reduction. That is 140 MB of new application can be added to Live CD if FreeArc is used instead of lzma . ]]