<sect1 id="memory">
<sect1info>

<authorgroup>

<author>
<firstname>Mike</firstname>
<surname>McBride</surname>
</author>

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</authorgroup>
        
<date>2001-07-22</date>
<releaseinfo>2.20.00</releaseinfo>

<keywordset>
<keyword>KDE</keyword>
<keyword>KControl</keyword>
<keyword>memory</keyword>
<keyword>system information</keyword>
</keywordset>
</sect1info>

<title>Memory Information</title>

<para>This module displays the current memory usage.  It is updated
constantly, and can be very useful for pinpointing bottlenecks when certain
applications  are executed.</para>

<sect2 id="memory-intro">
<title>Memory Types</title>

<para>The first thing you must understand, is there are two types of
<quote>memory</quote>, available to the operating system and the programs
that run within  it.</para>

<para>The first type, is called physical memory.  This is the memory located
within the memory chips, within your computer.  This is the
<acronym>RAM</acronym> (for Random Acess Memory) you bought when you
purchased your  computer.</para>

<para>The second type of memory, is called virtual or swap memory.  This
block of memory, is actually space on the hard drive.  The operating
system reserves a space on the hard drive for <quote>swap space</quote>.
The operating system can use this virtual memory (or swap space), if it
runs out of physical memory.  The reason this is called
<quote>swap</quote> memory, is the operating system takes some data that
it doesn't think you will want for a while, and saves that to disk in
this reserved space.  The operating system then loads the new data you
need right now.  It has <quote>swapped</quote> the not needed data, for
the data you need right now.  Virtual or swap memory is not as fast as
physical memory, so operating systems try to keep data (especially often
used data), in the physical memory.</para>

<para>The total memory, is the combined total of physical memory and
virtual memory.</para>

</sect2>

<sect2 id="memory-use">
<title>Memory Information Module</title>

<para>This window is divided into a top and bottom section</para>

<para>The top section shows you the total physical memory, total free
 physical memory, shared memory, and buffered memory.</para>

<para>All four values are represented as the total number of bytes, and
 as the number of megabytes (1 megabyte = slightly more than 1,000,000
 bytes)</para>

<para>The bottom section shows you three graphs:  </para>

<itemizedlist>
<listitem><para>Total memory (this is the combination of physical and
 virtual
memory).</para></listitem>
<listitem><para>Physical Memory.</para></listitem>
<listitem><para>Virtual (or swap) memory.</para></listitem>
</itemizedlist>

<para>The green areas are free, and the red areas are used.</para>

<tip><para>The exact values of each type of memory are not critical, and
 they change regularly.  When you evaluate this page, look at
 trends.</para>

<para>Does your computer have plenty of free space (green areas)?  If
 not, you can increase the swap size or increase the physical
 memory.</para>

<para>Also, if your computer seems sluggish: Is your physical memory
 full, and is the hard drive always seem to be running?  This suggests
 that you do not have enough physical memory, and your computer is
 relying on the slower virtual memory for commonly used data. Increasing
 your physical memory will improve the responsivness of your
 computer.</para></tip>

</sect2>

<sect2 id="memory-author">
<title>Section Author</title>

<para> Michael McBride <email>mpmcbride7@yahoo.com</email></para>
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</sect2>
</sect1>

