Disk space on partitions: df or prtvtoc?

[Nathan Cuka]

Hello,

I am trying to determine the amount of space on the partitions of
my internal hardrive. To this end I have used both df -k and
prtvtoc /dev/rdsk/c0t0d0s2 (the internal drive is at target 0 on
this machine). The thing is that prtvtoc is less by ~20Meg even after
adjusting for the small amount of unallocated space. My method
for determining the amount of space with prtvotc is to multiply
the total number of sectors by the value of 512 bytes/sector given
by the program.

I would have thought that df -k would have been on the low side,
since it counts free disk space and thus probably wouldn't count
space set aside for inodes, emergency crash space, etc...

Does anyone know which one is more correct? Or how df -k determines
the total amount of space, space used, and space available?

Also, does anyone know how to display the amount of space held back
from normal users on a disk? I know tunefs -m sets it, but how do
find out what it is?

I am running Solaris 2.5 on a Sun Ultra 1.

Thanks in advance...

Nathan Cuka
Nuclear Structure Laboratory
nc...@altair.phys.nd.edu