where's my memory?

[Steven P. Ulrick]

> I have a argument with another user about memory.  He claims that on running 
> linux on his 4G Dell machine, top only reports 3.something memory, he says 
> the missing space is for pci bus.  I think this is only because he's running 
> 32 bit and that 64 bit would give all the memory.
> 
> I tried on my 64bit 8G machine, and it reports
> 8114688k total
> 8114688 * 1024 = 8309440512 (assuming top 'k' is 1024)
> 2**33 = 8589934592
> The diff is:
>  280494080
> 
> I know some will be kernel space, but that doesn't account for 280M.

Hello Everyone
Since the topic has been started, here is what I am sure is a grade school 
level memory question:
My system has an Intel Xeon 2GHZ QuadCore processor with 8 gigabytes of RAM.  
Right now, "top" says the following:
Mem:	8108356k total,	7971312k used,	137176k free,		517972k 	buffers
Swap:	1507320k total,	2244k used,		1505076k free,	6308168k cached

To me, that looks like almost all of my memory is being used.  This is on a 
system which is relatively idle right now.

"ksysguard" says that about 1.1 GiB of 7.7 GiB is being used.
"gnome-system-monitor" says the same thing "ksysguard" says.
Actually, "gnome-system-monitor" says one thing different: that my system is 
using 2.2 MiB of Swap...

So I guess I am wondering what does "top" mean when it says that almost all of 
my memory is BEING used at the same time that the KDE and GNOME system 
monitoring tools say that only about 1.1 GiB is being used?

Steven P. Ulrick