apps/doc/kinfocenter/memory/index.docbook

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   8 <article lang="&language;">
   9 <title>Memory Information</title>
  10 <articleinfo>
  11
  12 <authorgroup>
  13 <author>&Mike.McBride;</author>
  14
  15 <!-- TRANS:ROLES_OF_TRANSLATORS -->
  16
  17 </authorgroup>
  18
  19 <date>2002-02-13</date>
  20 <releaseinfo>3.00.00</releaseinfo>
  21
  22 <keywordset>
  23 <keyword>KDE</keyword>
  24 <keyword>KControl</keyword>
  25 <keyword>memory</keyword>
  26 <keyword>system information</keyword>
  27 </keywordset>
  28 </articleinfo>
  29
  30 <sect1>
  31 <title>Memory Information</title>
  32
  33 <para>This module displays the current memory usage.  It is updated
  34 constantly, and can be very useful for pinpointing bottlenecks when certain
  35 applications  are executed.</para>
  36
  37 <sect2 id="memory-intro">
  38 <title>Memory Types</title>
  39
  40 <para>The first thing you must understand, is there are two types of
  41 <quote>memory</quote>, available to the operating system and the programs
  42 that run within  it.</para>
  43
  44 <para>The first type, is called physical memory.  This is the memory located
  45 within the memory chips, within your computer.  This is the
  46 <acronym>RAM</acronym> (for Random Access Memory) you bought when you
  47 purchased your  computer.</para>
  48
  49 <para>The second type of memory, is called virtual or swap memory.  This
  50 block of memory, is actually space on the hard drive.  The operating
  51 system reserves a space on the hard drive for <quote>swap space</quote>.
  52 The operating system can use this virtual memory (or swap space), if it
  53 runs out of physical memory.  The reason this is called
  54 <quote>swap</quote> memory, is the operating system takes some data that
  55 it doesn't think you will want for a while, and saves that to disk in
  56 this reserved space.  The operating system then loads the new data you
  57 need right now.  It has <quote>swapped</quote> the not needed data, for
  58 the data you need right now.  Virtual or swap memory is not as fast as
  59 physical memory, so operating systems try to keep data (especially often
  60 used data), in the physical memory.</para>
  61
  62 <para>The total memory, is the combined total of physical memory and
  63 virtual memory.</para>
  64
  65 </sect2>
  66
  67 <sect2 id="memory-use">
  68 <title>Memory Information Module</title>
  69
  70 <para>This window is divided into a top and bottom section</para>
  71
  72 <para>The top section shows you the total physical memory, total free
  73  physical memory, shared memory, and buffered memory.</para>
  74
  75 <para>All four values are represented as the total number of bytes, and
  76  as the number of megabytes (1 megabyte = slightly more than 1,000,000
  77  bytes)</para>
  78
  79 <para>The bottom section shows you three graphs:  </para>
  80
  81 <itemizedlist>
  82 <listitem><para><guilabel>Total Memory</guilabel> (this is the combination of physical and  virtual memory).</para></listitem>
  83 <listitem><para><guilabel>Physical Memory</guilabel></para></listitem>
  84 <listitem><para>Virtual memory, or <guilabel>Swap Space</guilabel>.</para></listitem>
  85 </itemizedlist>
  86
  87 <para>The green areas are free, and the red areas are used.</para>
  88
  89 <tip><para>The exact values of each type of memory are not critical, and
  90  they change regularly.  When you evaluate this page, look at
  91  trends.</para>
  92
  93 <para>Does your computer have plenty of free space (green areas)?  If
  94  not, you can increase the swap size or increase the physical
  95  memory.</para>
  96
  97 <para>Also, if your computer seems sluggish: is your physical memory
  98  full, and does the hard drive always seem to be running?  This suggests
  99  that you do not have enough physical memory, and your computer is
 100  relying on the slower virtual memory for commonly used data. Increasing
 101  your physical memory will improve the responsiveness of your
 102  computer.</para></tip>
 103
 104 </sect2>
 105
 106 </sect1>
 107
 108 </article>