I have a few questions regarding 7-zip.

1>What are the advantages of 7-zip?

2>Are the appilations made by 7-zip silent?

3>If we put 7-zip installers in our unattended cd the is there any effect o installation process?

(means effect in speed)

1) 7-zip has a high compression ratio for its archives, so the files are stored in an archive smaller than zip, bz2, gz and most of the time rar or ace.

2) The SFX of 7-zip does not create a silent installer by default, but its easy to configure to create a silent installer (many tutorials here)

3) The only effect you have with the install is you require 7za.exe (the command-line version of 7-zip) to be in the system directory. This can be achieved by placing it in the $OEM$\system32 folder of the cd or by adding it to the [sourceDisksFiles] of txtsetup.sif and placing it in the i386 directory of the cd (dont forget to makecab it)

Basically people use 7-zip to archive their files to reduce the footprint of the cd. There are other utilities you can use to do this but this is a common one here.