hw.physmem (loader.conf and sysctl)

[Dmitry Krivenok]

Hello Hackers,
I've limited the amount of physical memory visible for my FreeBSD-8.2 by adding
the following in loader.conf:

$ cat /boot/loader.conf | grep hw.physmem
hw.physmem="500M"
$

However, according to sysctl, the system sees

$ sysctl hw.physmem
hw.physmem: 507445248
$

The difference is (500 * 2**20 - 507445248) / 2**20 == 16.0625 Mb.
How does the system use this "hidden" memory?

Thanks!

-- 
Sincerely yours, Dmitry V. Krivenok
e-mail: krivenok.dmitry at gmail.com
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