[nSLUG] Help: CPAN session "killed", "0-order allocation failed"

Daniel Morrison draker at gmail.com
Wed May 13 18:40:49 ADT 2009

2009/5/13 Ian Campbell <ian at slu.ms>:
> top reports the
> amount of memory in use including buffers/cache. Free does too, but it
> also gives you the real number which is somewhat more useful.

Both 'top' and 'free' report both the total memory in use including
buffers/cache, and the size of the memory used only by buffers and by

What 'free' does for you which 'top' does not is the
addition/subtraction, so that you can quickly see (on free's second
line of data) how much memory is definitively allocated to processes,
and how much could be available for new processes if all the buffers
and cache were purged. These are not "real" numbers with regard to
free memory though, only projections of what is possible. Your
computer would likely be noticeably slower if you really didn't have
that memory available for buffers and cache.

'free' also has these handy switches:

-b,-k,-m,-g show output in bytes, KB, MB, or GB

which can show you in easier-to-comprehend units what your memory
situation is. If only 'top' reported memory sizes in MB, it would be
easier to do your own calculation of "potentially free memory" without
smudging the screen with your finger, trying to count digits, or
giving up, quitting top and typing 'free' instead! :)


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