Sysvalues - memory usage?

[Helmut Metzdorf <h-j-m@tap.de>]

Hi,

just beeing curious i'm interested about the meaning of following
displayed sysvalues.

after boot, free shows:

             total       used       free     shared    buffers     cached
Mem:         39056      22428      16628      20028       1316       8968
-/+ buffers/cache:      12144      26912

to reproduce same starting conditions i do a shutdown -r,
then start a program in background. after several minutes (to make 
shure all files have beeen worked through at least once) free shows
the following:

Swap:        66524          0      66524
             total       used       free     shared    buffers     cached
Mem:         39056      27448      11608      20376       1764      13384
-/+ buffers/cache:      12300      26756
Swap:        66524          0      66524

increased memory usage (cached)   4416K   
increased memory usage (buffers)   448K

about the proramm run:
-rwxr-xr-x   1 hjm      hjm         60648 Nov  4 01:07 programm
-rw-rw-r--   1 hjm      hjm           916 Nov  5 23:16 datafile1
-rw-rw-r--   1 hjm      hjm          5172 Nov  5 23:18 datafile2
-rw-rw-r--   1 hjm      hjm       4040864 Oct 23 19:33 datafile3
-rw-r--r--   1 hjm      hjm         12576 Oct 23 19:24 datafile4
-rw-rw-r--   1 hjm      hjm         10824 Nov  5 22:29 datafile5
-rw-rw-r--   1 hjm      hjm          6312 Nov  5 23:16 datafile6
-rw-rw-r--   1 hjm      hjm        350556 Nov  5 23:18 datafile7

summary:

program + used files              4487868 total

increased memory usage            4864K 

interpretation ?????????

please don't answer, otherwise i may hold you resposible for
(to respond to) the zillion questions to follow.

Helmut