=back
RRDtool is designed to store time series of data. With every data
-update, an assosiated time stamp is stored. Time is always expressed
-in seconds passed since epoch (01-01-1971). RRDtool can be installed
+update, an associated time stamp is stored. Time is always expressed
+in seconds passed since epoch (01-01-1970). RRDtool can be installed
on Unix as well as Windows. It comes with a command set to carry out
various operations on RRD databases. This command set can be accessed
from the command line, as well as from Shell or Perl scripts. The
other number which might also be a valid data value. For example, the
traffic flow counter on a router keeps increasing. Lets say, a value
is missed for an interval and 0 is stored instead of UNKNOWN. Now when
-hte next value becomes available, it will calculate the difference
+the next value becomes available, it will calculate the difference
between the current value and the previous value (0) which is not
correct. So, inserting the value UNKNOWN makes much more sense here.