Just looking for a short overview of GAC for a layman, not a link please.
Right, so basically it's a way to keep DLLs globally accessible without worrying about conflicts. No more DLL Hell. Each architecture and version gets it's own place to live.
It also gets it own way to browse it in Explorer, so if you go to
C:\Windows\assembly
In windows explorer it lists all the DLLs.
But if you fire up cmd, you can see how it's really structured:
C:\Users\tritter>cd C:\Windows\assembly
C:\Windows\assembly>dir
Directory of C:\Windows\assembly
07/20/2009 02:18 PM <DIR> GAC
06/17/2009 04:22 PM <DIR> GAC_32
06/17/2009 04:22 PM <DIR> GAC_64
06/17/2009 04:22 PM <DIR> GAC_MSIL
...snip...
0 File(s) 0 bytes
9 Dir(s) 90,538,311,680 bytes free
C:\Windows\assembly>cd GAC_64
C:\Windows\assembly\GAC_64>dir
Directory of C:\Windows\assembly\GAC_64
06/17/2009 04:22 PM <DIR> .
06/17/2009 04:22 PM <DIR> ..
01/19/2008 09:54 AM <DIR> blbproxy
...snip...
01/19/2008 09:54 AM <DIR> srmlib
01/19/2008 06:11 AM <DIR> System.Data
01/19/2008 06:11 AM <DIR> System.Data.OracleClient
...snip...
0 File(s) 0 bytes
34 Dir(s) 90,538,311,680 bytes free
C:\Windows\assembly\GAC_64>cd System.Data
C:\Windows\assembly\GAC_64\System.Data>dir
Directory of C:\Windows\assembly\GAC_64\System.Data
01/19/2008 06:11 AM <DIR> .
01/19/2008 06:11 AM <DIR> ..
04/11/2009 12:20 PM <DIR> 2.0.0.0__b77a5c561934e089
0 File(s) 0 bytes
3 Dir(s) 90,538,311,680 bytes free
C:\Windows\assembly\GAC_64\System.Data>cd 2.0.0.0__b77a5c561934e089
C:\Windows\assembly\GAC_64\System.Data\2.0.0.0__b77a5c561934e089>dir
Directory of C:\Windows\assembly\GAC_64\System.Data\2.0.0.0__b77a5c561934e089
04/11/2009 12:20 PM <DIR> .
04/11/2009 12:20 PM <DIR> ..
04/11/2009 12:12 PM 3,008,512 System.Data.dll
1 File(s) 3,008,512 bytes
2 Dir(s) 90,538,311,680 bytes free
C:\Windows\assembly\GAC_64\System.Data\2.0.0.0__b77a5c561934e089>
Here you can see version 2.0.0.0__b77a5c561934e089 of System.Data.
A DLL is identified by 5 parts:
Although the first 3 are generally the big ones.