ch8.htm

汤子瀛《操作系统》电子教案

      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">当前目录</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p><font color="#FFFFFF"><span style="mso-spacerun: yes; mso-bidi-font-size: 10.0pt" lang="EN-US">&nbsp;&nbsp; 
      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">增加和删除目录</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l24 level1 lfo24"><font color="#FFFFFF"><span lang="EN-US" style="mso-fareast-font-family: 黑体">5．</span><span style="mso-ascii-font-family: Times New Roman">目录查询技术</span><span lang="EN-US" style="mso-fareast-font-family: 黑体"><o:p>
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      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">线性检索技术（顺序检索法）</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span lang="EN-US" style="mso-bidi-font-size: 10.0pt">Hash</span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">检索技术</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p style="MARGIN-LEFT: 18pt"><span lang="EN-US"><font color="#FFFFFF">&nbsp;<o:p>
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      <p style="TEXT-ALIGN: center" align="center"><font color="#FFFFFF"><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><a name="ch84"></a>8</span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">．</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt">4<span style="mso-spacerun: yes">&nbsp; 
      </span></span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">文件共享</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l21 level1 lfo22"><font color="#FFFFFF"><span lang="EN-US" style="mso-fareast-font-family: 黑体">1．</span><span style="mso-ascii-font-family: Times New Roman">早期实现文件共享的办法</span><span lang="EN-US" style="mso-fareast-font-family: 黑体"><o:p>
      </o:p>
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      <p><font color="#FFFFFF"><span style="mso-spacerun: yes" lang="EN-US">&nbsp; 
      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">⑴绕弯路法</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p><font color="#FFFFFF"><span style="mso-spacerun: yes; mso-bidi-font-size: 10.0pt" lang="EN-US">&nbsp; 
      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">⑵连访法</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p><font color="#FFFFFF"><span style="mso-spacerun: yes; mso-bidi-font-size: 10.0pt" lang="EN-US">&nbsp; 
      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">⑶利用基本文件目录实现文件共享</span></font></p>
      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l21 level1 lfo22"><font color="#FFFFFF"><span lang="EN-US" style="mso-fareast-font-family: 黑体">2．</span><span style="mso-ascii-font-family: Times New Roman">基于索引结点的共享方式</span><span lang="EN-US" style="mso-fareast-font-family: 黑体"><o:p>
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      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l21 level1 lfo22"><font color="#FFFFFF"><span lang="EN-US">3．</span><span style="mso-ascii-font-family: Times New Roman">利用符号链实现文件共享</span></font></p>
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      <p style="TEXT-ALIGN: center" align="center"><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><font color="#FFFFFF"><a name="ch85"></a>8．5<span style="mso-spacerun: yes">&nbsp; 
      </span>文件保护<o:p>
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      <p><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">影响文件安全性的主要因素有：</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p><font color="#FFFFFF"><span style="mso-spacerun: yes; mso-bidi-font-size: 10.0pt" lang="EN-US">&nbsp; 
      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">人为因素；系统因素；自然因素。</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
      </span></font></p>
      <p><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">通过存取控制机制来防止人为因素所造成的文件不安全性；</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
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      <p><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">通过系统容错技术来防止系统部分故障所造成的文件不安全性；</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
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      <p><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman"><font color="#FFFFFF">通过“后备系统”来防止由自然因素所造成的不安全性。</font></span></p>
      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l20 level1 lfo28"><font color="#FFFFFF"><span lang="EN-US" style="mso-fareast-font-family: 黑体">1．</span><span style="mso-ascii-font-family: Times New Roman">保护域</span><span lang="EN-US" style="mso-fareast-font-family: 黑体"><o:p>
      </o:p>
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      <p><font color="#FFFFFF"><span style="mso-spacerun: yes; mso-bidi-font-size: 10.0pt" lang="EN-US">&nbsp;&nbsp; 
      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">静态联系</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
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      <p><font color="#FFFFFF"><span style="mso-spacerun: yes; mso-bidi-font-size: 10.0pt" lang="EN-US">&nbsp;&nbsp; 
      </span><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">动态联系</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
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      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l20 level1 lfo28"><font color="#FFFFFF"><span lang="EN-US" style="mso-fareast-font-family: 黑体">2．</span><span style="mso-ascii-font-family: Times New Roman">访问矩阵</span><span lang="EN-US" style="mso-fareast-font-family: 黑体"><o:p>
      </o:p>
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      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l20 level1 lfo28"><font color="#FFFFFF"><span lang="EN-US">3．</span><span style="mso-ascii-font-family: Times New Roman">访问矩阵的修改</span></font></p>
      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">拷贝权；</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
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      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">所有权；</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
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      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">控制权</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
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      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l20 level1 lfo28"><font color="#FFFFFF"><span lang="EN-US" style="mso-fareast-font-family: 黑体">4．</span><span style="mso-ascii-font-family: Times New Roman">访问矩阵的实现</span><span lang="EN-US" style="mso-fareast-font-family: 黑体"><o:p>
      </o:p>
      </span></font></p>
      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">访问控制表：</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
      </span></font></p>
      <p style="MARGIN-LEFT: 18pt"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman"><font color="#FFFFFF">访问权限表：</font></span></p>
      <p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; tab-stops: list 18.0pt; mso-list: l20 level1 lfo28"><font color="#FFFFFF"><span lang="EN-US" style="mso-fareast-font-family: 黑体">5．</span><span style="mso-ascii-font-family: Times New Roman">分级安全管理</span><span lang="EN-US" style="mso-fareast-font-family: 黑体"><o:p>
      </o:p>
      </span></font></p>
      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">系统级安全管理</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
      </span></font></p>
      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">用户级安全管理</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
      </span></font></p>
      <p style="MARGIN-LEFT: 18pt"><font color="#FFFFFF"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">目录级安全管理</span><span lang="EN-US" style="mso-bidi-font-size: 10.0pt"><o:p>
      </o:p>
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      <p style="MARGIN-LEFT: 18pt"><span style="mso-bidi-font-size: 10.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman"><font color="#FFFFFF">文件及安全管理</font></span></p>
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