Debian showing less RAM

[Muhammad Yousuf Khan <sirtcp@gmail.com>]

i am using debian 6.0.4. i have 8GB of ram installed in a server 2GB x
4. bios also shows 8 GB.

however top only shows 2gb or RAM

top - 15:48:29 up 16 min,  1 user,  load average: 0.00, 0.01, 0.00
Tasks:  90 total,   1 running,  89 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.1%sy,  0.0%ni, 99.6%id,  0.3%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   2273280k total,    79768k used,  2193512k free,     2292k buffers
Swap: 15623088k total,        0k used, 15623088k free,    45456k cached


root@lion:~# free
             total       used       free     shared    buffers     cached
Mem:       2273280      79768    2193512          0       2292      45456
-/+ buffers/cache:      32020    2241260
Swap:     15623088          0   15623088


Secondly.........

root@lion:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/pve--vg-root
                      442G  550M  419G   1% /

i dont know if its normal but things are confusing me a bit. i have
working space of 442G  used 550MB and available 419MB there almost
22GB is missing.

please help.

Thanks,