3-4.htm

计算机操作系统 西安电子科技大学出版社 操作系统实验

mso-hansi-font-family:"Times New Roman"'>：回顾系统进程概念。</span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>每个运行的程序都会创建一个进程，进程分配到一个唯一的进程标识符</span><span
lang=EN-US> (PID) </span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>。</span><span
lang=EN-US>PID</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>被系统用于标识和跟踪进程，直到进程结束。操作系统内核管理所有进程的初始化和终止。每一个进程都要求系统资源</span><span
lang=EN-US> (</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>例如</span><span lang=EN-US>CPU</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>时间和</span><span lang=EN-US>RAM</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>空间</span><span
lang=EN-US>) </span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>在其中工作。当进程启动的时候，操作系统把系统资源分配给每个进程，当进程终止的时候，系统回收这些资源。在</span><span
lang=EN-US>Linux</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>系统启动的时候，首先启动的两个进程是</span><span
lang=EN-US>sched (</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>调度</span><span
lang=EN-US>) </span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>和</span><span lang=EN-US>init (</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>初始化</span><span lang=EN-US>) </span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>，它们管理着其他进程。</span><span
lang=EN-US>Linux</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>系统中有几种不同类型的进程：</span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>守护进程：由</span><span
lang=EN-US>Linux</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>内核启动的进程，为了特定目的而存在。例如，</span><span
lang=EN-US>lpsched</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>守护进程存在只是为了处理打印作业。</span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>父进程：派生其他进程的进程是父进程。一个叫做</span><span
lang=EN-US>init</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>的守护进程是第一个调用的进程。每一个进程，除了</span><span
lang=EN-US>init</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>之外，都有一个父进程。</span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>子进程：由其他进程派生出来的进程叫做子进程。</span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>孤儿进程：在进程返回输出之前，它的父进程结束了，这样的进程叫做孤儿进程。</span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>僵进程：子进程没有带着输出返回给父进程。这样的进程在系统中变成丢失的进程。</span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><a name="_Toc36947215"><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>使用此前的信息，完成以下填空：</span></a></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>1) Linux</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>系统中，几乎每一个启动的进程，都会由内核分配一个唯一的</span><span lang=EN-US>_______________</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>进程标识符，用于跟踪从进程启动到进程结束。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>2) </span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>当启动新进程的时候，内核也给它们分配系统资源，如</span><span lang=EN-US>________</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>和</span><span
lang=EN-US>________</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>3) </span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>永远不向父进程返回输出的进程叫做</span><span lang=EN-US>______________</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>4) </span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>由父进程派生出来的进程叫做</span><span lang=EN-US>__________________</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>进程。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>5) ________________</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>进程是一个派生另一个进程的进程。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>6) </span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>运行用于提供服务的</span><span lang=EN-US>Linux</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>系统进程是</span><span
lang=EN-US>_______________</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>7) </span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>如果父进程在子进程之前结束，它创建了一个</span><span lang=EN-US>______________</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>进程。</span></span></p>

<p class=MsoNormal style='text-indent:21.1pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.55pt'><span style='mso-bookmark:_Toc36947215'><b
style='mso-bidi-font-weight:normal'><span style='font-family:楷体_GB2312;
mso-ascii-font-family:"Times New Roman"'>步骤</span></b></span><span
style='mso-bookmark:_Toc36947215'><b style='mso-bidi-font-weight:normal'><span
lang=EN-US style='mso-fareast-font-family:楷体_GB2312'>4</span></b></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>：回顾</span><span
lang=EN-US>ps</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>命令和信息。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>ps</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>命令用于列出当前系统中运行的进程。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>如果一个进程耗时太长，或者看上去好像已经终止了，表现为一个终端窗口不再响应或挂起，通常需要使用</span><span
lang=EN-US>ps</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>查看系统中的进程。通过列出进程，可以查看初始化进程的命令或程序的名字，以及所有它派生出来的子进程。通过多次执行</span><span
lang=EN-US>ps</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>命令，查看进程的时间——进程占用的</span><span lang=EN-US>CPU</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>时间，可以检查一个进程是否还在运行。如果时间小再增长，那么进程可能已经终止了。如果进程占用太长的时间或者已经停止，可以使用</span><span
lang=EN-US>ps</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>命令检查进程的进程</span><span lang=EN-US>ID (PID) </span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>，然后杀死进程。</span></span></p>

<p class=MsoNormal style='text-indent:21.0pt;mso-char-indent-count:2.0;
mso-char-indent-size:10.5pt'><span style='mso-bookmark:_Toc36947215'><span
lang=EN-US>ps</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>命令的输出将显示</span><span lang=EN-US>PID</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>号和与其相关的命令或程序。</span><span
lang=EN-US>PID</span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>号通常用于终止一个进程。</span><span lang=EN-US>ps</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>命令</span><span
lang=EN-US> ( ps [-options] ) </span></span><span style='mso-bookmark:_Toc36947215'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>的</span><span lang=EN-US>3</span></span><span
style='mso-bookmark:_Toc36947215'><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>个主要选项如下表所示。</span></span></p>

<p class=MsoNormal><span style='mso-bookmark:_Toc36947215'><span lang=EN-US>&nbsp;</span></span></p>

<p class=a><span style='mso-bookmark:_Toc36947215'>表<span lang=EN-US>3-5<span
style="mso-spacerun: yes">&nbsp; </span>ps命令选项<o:p></o:p></span></span></p>

<div align=center>

<table border=1 cellspacing=0 cellpadding=0 style='margin-left:5.4pt;
 border-collapse:collapse;border:none;mso-border-top-alt:solid windowtext 1.5pt;
 mso-border-bottom-alt:solid windowtext 1.5pt;mso-padding-alt:0cm 5.4pt 0cm 5.4pt'>
 <tr style='height:17.0pt;mso-yfti-irow:0'>
  <td width=94 style='width:70.55pt;border-top:solid windowtext 1.5pt;
  border-left:none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt;
  padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>
  <p class=a><span style='mso-bookmark:_Toc36947215'><span lang=EN-US>ps选项</span></span></p>
  </td>
  <span style='mso-bookmark:_Toc36947215'></span>
  <td width=80 style='width:60.0pt;border-top:solid windowtext 1.5pt;
  border-left:none;border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt;
  mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt;
  height:17.0pt'>
  <p class=a><span style='mso-bookmark:_Toc36947215'>意义</span></p>
  </td>
  <span style='mso-bookmark:_Toc36947215'></span>
  <td width=336 style='width:251.95pt;border-top:solid windowtext 1.5pt;
  border-left:none;border-bottom:solid windowtext .5pt;border-right:none;
  mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt;
  height:17.0pt'>
  <p class=a><span style='mso-bookmark:_Toc36947215'>功能</span></p>
  </td>
  <span style='mso-bookmark:_Toc36947215'></span>
 </tr>
 <tr style='height:17.0pt;mso-yfti-irow:1'>
  <td width=94 style='width:70.55pt;border-top:none;border-left:none;
  border-bottom:solid windowtext .5pt;border-right:solid windowtext .5pt;
  mso-border-top-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt;
  height:17.0pt'>
  <p class=MsoNormal style='text-indent:9.0pt;mso-char-indent-count:1.0;
  mso-char-indent-size:9.0pt;mso-char-indent-size:9pt'><span style='mso-bookmark:
  _Toc36947215'><span lang=EN-US style='font-size:9.0pt;mso-bidi-font-size:
  12.0pt'>Ps<o:p></o:p></span></span></p>
  </td>
  <span style='mso-bookmark:_Toc36947215'></span>
  <td width=80 style='width:60.0pt;border-top:none;border-left:none;border-bottom:
  solid windowtext .5pt;border-right:solid windowtext .5pt;mso-border-top-alt:
  solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;padding:0cm 5.4pt 0cm 5.4pt;
  height:17.0pt'>
  <p class=MsoHeader style='tab-stops:21.0pt center 207.65pt right 415.3pt;
  layout-grid-mode:both;border:none;mso-padding-alt:0cm 0cm 0cm 0cm'><span
  style='mso-bookmark:_Toc36947215'><span style='mso-bidi-font-size:12.0pt;
  font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
  "Times New Roman"'>无选项</span></span><span style='mso-bookmark:_Toc36947215'><span
  lang=EN-US style='mso-bidi-font-size:12.0pt'><o:p></o:p></span></span></p>
  </td>
  <span style='mso-bookmark:_Toc36947215'></span>
  <td width=336 style='width:251.95pt;border:none;border-bottom:solid windowtext .5pt;
  mso-border-top-alt:solid windowtext .5pt;mso-border-left-alt:solid windowtext .5pt;
  padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt'>
  <p class=MsoNormal style='text-indent:9.0pt;mso-char-indent-count:1.0;
  mso-char-indent-size:9.0pt;mso-char-indent-size:9pt'><span style='mso-bookmark:
  _Toc36947215'><span style='font-size:9.0pt;mso-bidi-font-size:12.0pt;
  font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
  "Times New Roman"'>显示当前</span></span><span style='mso-bookmark:_Toc36947215'><span
  lang=EN-US style='font-size:9.0pt;mso-bidi-font-size:12.0pt'>shell</span></span><span
  style='mso-bookmark:_Toc36947215'><span style='font-size:9.0pt;mso-bidi-font-size:
  12.0pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
  "Times New Roman"'>或终端窗口中，当前用户的进程信息</span></span><span style='mso-bookmark:
  _Toc36947215'><span lang=EN-US style='font-size:9.0pt;mso-bidi-font-size:
  12.0pt'><o:p></o:p></span></span></p>
  </td>