From: ohland@charter.net   
      
   The .cab filename extension is also used by other installer programs   
   (e.g. InstallShield) for their own proprietary archiving formats.   
   InstallShield uses zlib for compression (see Deflate), but their headers   
   are not the same as for Microsoft CAB files so they are incompatible and   
   cannot be manipulated or edited with the programs that are made for   
   standard cabinet format. Specialized third-party utilities, such as   
   Unshield, can extract this specific proprietary format.[18] This format   
   has a different magic number of ISC(.[19]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)