<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8">
<meta name="generator" content="pdf2htmlEX">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<link rel="stylesheet" href="https://static.pudn.com/base/css/base.min.css">
<link rel="stylesheet" href="https://static.pudn.com/base/css/fancy.min.css">
<link rel="stylesheet" href="https://static.pudn.com/prod/directory_preview_static/626cab176ed7575b4d513dab/raw.css">
<script src="https://static.pudn.com/base/js/compatibility.min.js"></script>
<script src="https://static.pudn.com/base/js/pdf2htmlEX.min.js"></script>
<script>
try{
pdf2htmlEX.defaultViewer = new pdf2htmlEX.Viewer({});
}catch(e){}
</script>
<title></title>
</head>
<body>
<div id="sidebar" style="display: none">
<div id="outline">
</div>
</div>
<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626cab176ed7575b4d513dab/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0"> <span class="ff2 fs1">实验三、存储管理</span></div><div class="t m0 x1 h4 y3 ff2 fs2 fc0 sc1 ls0 ws0">一、实验目的：</div><div class="t m0 x1 h5 y4 ff3 fs0 fc0 sc0 ls0 ws0"><span class="_ _0"></span><span class="ff2">一个好的计算<span class="_ _0"></span>机系统不仅要有一<span class="_ _0"></span>个足够容量的、存<span class="_ _0"></span>取速度高的、稳定<span class="_ _0"></span>可靠的主存储器，</span></div><div class="t m0 x1 h5 y5 ff2 fs0 fc0 sc0 ls0 ws0">而且<span class="_ _0"></span>要能合<span class="_ _0"></span>理地<span class="_ _0"></span>分配和<span class="_ _0"></span>使用这<span class="_ _0"></span>些存储<span class="_ _0"></span>空间。<span class="_ _0"></span>当用<span class="_ _0"></span>户提出<span class="_ _0"></span>申请存<span class="_ _0"></span>储器<span class="_ _0"></span>空间时<span class="_ _0"></span>，存储<span class="_ _0"></span>管理<span class="_ _0"></span>必须</div><div class="t m0 x1 h5 y6 ff2 fs0 fc0 sc0 ls0 ws0">根据<span class="_ _0"></span>申请者<span class="_ _0"></span>的要<span class="_ _0"></span>求，按<span class="_ _0"></span>一定的<span class="_ _0"></span>策略分<span class="_ _0"></span>析主存<span class="_ _0"></span>空间<span class="_ _0"></span>的使用<span class="_ _0"></span>情况，<span class="_ _0"></span>找出<span class="_ _0"></span>足够的<span class="_ _0"></span>空闲区<span class="_ _0"></span>域分<span class="_ _0"></span>配给</div><div class="t m0 x1 h5 y7 ff2 fs0 fc0 sc0 ls0 ws0">申请<span class="_ _0"></span>者。当<span class="_ _0"></span>作业<span class="_ _0"></span>撤离或<span class="_ _0"></span>主动归<span class="_ _0"></span>还主存<span class="_ _0"></span>资源时<span class="_ _0"></span>，则<span class="_ _0"></span>存储管<span class="_ _0"></span>理要收<span class="_ _0"></span>回作<span class="_ _0"></span>业占用<span class="_ _0"></span>的主存<span class="_ _0"></span>空间<span class="_ _0"></span>或归</div><div class="t m0 x1 h5 y8 ff2 fs0 fc0 sc0 ls0 ws0">还部<span class="_ _0"></span>分主存<span class="_ _0"></span>空间<span class="_ _0"></span>。主存<span class="_ _0"></span>的分配<span class="_ _0"></span>和回收<span class="_ _0"></span>的实现<span class="_ _0"></span>虽与<span class="_ _0"></span>主存储<span class="_ _0"></span>器的管<span class="_ _0"></span>理方<span class="_ _0"></span>式有关<span class="_ _0"></span>的，通<span class="_ _0"></span>过本<span class="_ _0"></span>实验</div><div class="t m0 x1 h5 y9 ff2 fs0 fc0 sc0 ls0 ws0">理解在不同的存储管理方式下应怎样实现主存空间的分配和回收。</div><div class="t m0 x2 h5 ya ff2 fs0 fc0 sc0 ls0 ws0">在计<span class="_ _0"></span>算机系<span class="_ _0"></span>统中<span class="_ _0"></span>，为了<span class="_ _0"></span>提高主<span class="_ _0"></span>存利用<span class="_ _0"></span>率，往<span class="_ _0"></span>往把<span class="_ _0"></span>辅助存<span class="_ _0"></span>储器（<span class="_ _0"></span>如磁<span class="_ _0"></span>盘）作<span class="_ _0"></span>为主存<span class="_ _0"></span>储器</div><div class="t m0 x1 h5 yb ff2 fs0 fc0 sc0 ls0 ws0">的扩<span class="_ _0"></span>充，使<span class="_ _0"></span>多道<span class="_ _0"></span>运行的<span class="_ _0"></span>作业的<span class="_ _0"></span>全部逻<span class="_ _0"></span>辑地址<span class="_ _0"></span>空间<span class="_ _0"></span>总和可<span class="_ _0"></span>以超出<span class="_ _0"></span>主存<span class="_ _0"></span>的绝对<span class="_ _0"></span>地址空<span class="_ _0"></span>间。<span class="_ _0"></span>用这</div><div class="t m0 x1 h5 yc ff2 fs0 fc0 sc0 ls0 ws0">种办<span class="_ _0"></span>法扩充<span class="_ _0"></span>的主<span class="_ _0"></span>存储器<span class="_ _0"></span>称为虚<span class="_ _0"></span>拟存储<span class="_ _0"></span>器。通<span class="_ _0"></span>过本<span class="_ _0"></span>实验理<span class="_ _0"></span>解在分<span class="_ _0"></span>页式<span class="_ _0"></span>存储管<span class="_ _0"></span>理中怎<span class="_ _0"></span>样实<span class="_ _0"></span>现虚</div><div class="t m0 x1 h5 yd ff2 fs0 fc0 sc0 ls0 ws0">拟存储器。</div><div class="t m0 x2 h5 ye ff2 fs0 fc0 sc0 ls0 ws0">在本<span class="_ _0"></span>实验中<span class="_ _0"></span>，通<span class="_ _0"></span>过编写<span class="_ _0"></span>和调<span class="_ _0"></span>试存储<span class="_ _0"></span>管理的<span class="_ _0"></span>模拟<span class="_ _0"></span>程序以<span class="_ _0"></span>加深对<span class="_ _0"></span>存储<span class="_ _0"></span>管理方<span class="_ _0"></span>案的理<span class="_ _0"></span>解。熟</div><div class="t m0 x1 h5 yf ff2 fs0 fc0 sc0 ls0 ws0">悉虚<span class="_ _0"></span>存管理<span class="_ _0"></span>的各<span class="_ _0"></span>种页面<span class="_ _0"></span>淘汰算<span class="_ _0"></span>法通过<span class="_ _0"></span>编写和<span class="_ _0"></span>调试<span class="_ _0"></span>地址转<span class="_ _0"></span>换过程<span class="_ _0"></span>的模<span class="_ _0"></span>拟程序<span class="_ _0"></span>以加强<span class="_ _0"></span>对地<span class="_ _0"></span>址转</div><div class="t m0 x1 h5 y10 ff2 fs0 fc0 sc0 ls0 ws0">换过程的了解。</div><div class="t m0 x1 h4 y11 ff2 fs2 fc0 sc1 ls0 ws0">二、实验题目<span class="fs0">：</span></div><div class="t m0 x2 h5 y12 ff2 fs0 fc0 sc0 ls0 ws0">设计一个可变式分区分配的存储管理方案。并模拟实现分区的分配和回收过程。 </div><div class="t m0 x3 h5 y13 ff2 fs0 fc0 sc0 ls0 ws0">对分区的管理法可以是下面三种算法之一： <span class="fc1 sc2">（任选一种算法实现）</span></div><div class="t m0 x4 h5 y14 ff2 fs0 fc0 sc0 ls0 ws0">首次适应算法 </div><div class="t m0 x4 h5 y15 ff2 fs0 fc0 sc0 ls0 ws0">循环首次适应算法 </div><div class="t m0 x4 h5 y16 ff2 fs0 fc0 sc0 ls0 ws0">最佳适应算法</div><div class="t m0 x1 h4 y17 ff2 fs2 fc0 sc1 ls0 ws0">三．实验源程序文件名<span class="ff3 fs0 sc0"></span></div><div class="t m0 x1 h4 y18 ff3 fs0 fc0 sc0 ls0 ws0"><span class="fs2"><span class="ff2 sc1">执行文件名</span></span><span class="_ _0"></span></div><div class="t m0 x1 h4 y19 ff2 fs2 fc0 sc1 ls0 ws0">四、实验分析：</div><div class="t m0 x5 h6 y1a ff4 fs2 fc0 sc0 ls0 ws0">1)<span class="ff2 fs0">本实验采用可变分区管理，使用首次适应算法实现主存的分配和回收</span></div><div class="t m0 x2 h5 y1b ff3 fs0 fc0 sc0 ls0 ws0"><span class="_ _0"></span><span class="ff2">、可<span class="_ _0"></span>变分<span class="_ _0"></span>区<span class="_ _0"></span>管理<span class="_ _0"></span>是<span class="_ _0"></span>指在<span class="_ _0"></span>处理<span class="_ _0"></span>作<span class="_ _0"></span>业过<span class="_ _0"></span>程<span class="_ _0"></span>中建<span class="_ _0"></span>立分<span class="_ _0"></span>区<span class="_ _0"></span>，使<span class="_ _0"></span>分<span class="_ _0"></span>区大<span class="_ _0"></span>小正<span class="_ _0"></span>好<span class="_ _0"></span>适合<span class="_ _0"></span>作<span class="_ _0"></span>业的<span class="_ _0"></span>需求<span class="_ _1"></span>，</span></div><div class="t m0 x3 h5 y1c ff2 fs0 fc0 sc0 ls0 ws0">并且<span class="_ _0"></span>分区个<span class="_ _0"></span>数是<span class="_ _0"></span>可以调<span class="_ _0"></span>整的。<span class="_ _2"></span>当要<span class="_ _0"></span>装入一<span class="_ _0"></span>个作业<span class="_ _0"></span>时，<span class="_ _0"></span>根据作<span class="_ _0"></span>业需要<span class="_ _0"></span>的主存<span class="_ _0"></span>量查看<span class="_ _0"></span>是</div><div class="t m0 x3 h5 y1d ff2 fs0 fc0 sc0 ls0 ws0">否有<span class="_ _0"></span>足够的<span class="_ _0"></span>空闲<span class="_ _0"></span>空间，<span class="_ _0"></span>若有，<span class="_ _0"></span>则按需<span class="_ _0"></span>要量分<span class="_ _0"></span>割一<span class="_ _0"></span>个分区<span class="_ _0"></span>分配给<span class="_ _0"></span>该作<span class="_ _0"></span>业；若<span class="_ _0"></span>无，则<span class="_ _0"></span>作</div><div class="t m0 x3 h5 y1e ff2 fs0 fc0 sc0 ls0 ws0">业不<span class="_ _0"></span>能装入<span class="_ _0"></span>，作<span class="_ _0"></span>业等待<span class="_ _0"></span>。随着<span class="_ _0"></span>作业的<span class="_ _0"></span>装入、<span class="_ _0"></span>完成<span class="_ _0"></span>，主存<span class="_ _0"></span>空间被<span class="_ _0"></span>分成<span class="_ _0"></span>许多大<span class="_ _0"></span>大小小<span class="_ _0"></span>的</div><div class="t m0 x3 h5 y1f ff2 fs0 fc0 sc0 ls0 ws0">分区，有的分区被作业占用，而有的分区是空闲的。</div><div class="t m0 x6 h5 y20 ff2 fs0 fc0 sc0 ls0 ws0">为了说明那些分区是空闲的，可以用来装入新作业，必须有一张空闲说明表</div><div class="t m0 x1 h5 y21 ff3 fs0 fc0 sc0 ls0 ws0"><span class="ff2 fc2">空闲区说明表格式如下： </span></div><div class="t m0 x7 h7 y22 ff3 fs0 fc2 sc0 ls0 ws0"></div><div class="t m0 x8 h5 y23 ff2 fs0 fc2 sc0 ls0 ws0">起始地址<span class="_ _3"> </span>长度<span class="_ _4"> </span>状态</div><div class="t m0 x7 h5 y24 ff2 fs0 fc2 sc0 ls0 ws0">第一栏</div><div class="t m0 x9 h7 y25 ff3 fs0 fc2 sc0 ls0 ws0"><span class="_ _5"> </span></div><div class="t m0 xa h5 y24 ff2 fs0 fc2 sc0 ls0 ws0">未 分 配</div><div class="t m0 x7 h5 y26 ff2 fs0 fc2 sc0 ls0 ws0">第二栏</div><div class="t m0 x9 h7 y27 ff3 fs0 fc2 sc0 ls0 ws0"><span class="_ _6"> </span></div><div class="t m0 xa h5 y26 ff2 fs0 fc2 sc0 ls0 ws0">未 分 配</div><div class="t m0 x9 h7 y28 ff3 fs0 fc2 sc0 ls0 ws0"><span class="_ _7"> </span></div><div class="t m0 xa h5 y29 ff2 fs0 fc2 sc0 ls0 ws0">空 表 目</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
</body>
</html>
<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626cab176ed7575b4d513dab/bg2.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h5 y2a ff2 fs0 fc0 sc0 ls0 ws0">其中，起址——指出一个空闲区的主存起始地址，长度指出空闲区的大小。</div><div class="t m0 x1 h5 y2b ff3 fs0 fc0 sc0 ls0 ws0"><span class="ff2">长度——指出从起始地址开始的一个连续空闲的长度。</span></div><div class="t m0 x1 h5 y2c ff3 fs0 fc0 sc0 ls0 ws0"><span class="_ _0"></span><span class="_ _0"></span><span class="_ _0"></span><span class="_ _0"></span><span class="ff2">状<span class="_ _0"></span>态—<span class="_ _0"></span>—有<span class="_ _0"></span>两种<span class="_ _0"></span>状态<span class="_ _0"></span>，一<span class="_ _0"></span>种是<span class="_ _2"></span><span class="fc2">“<span class="_ _0"></span>未分<span class="_ _0"></span>配”<span class="_ _0"></span>状态<span class="_ _0"></span>，<span class="_ _0"></span></span>指<span class="_ _0"></span>出对<span class="_ _0"></span>应的<span class="_ _0"></span>由起<span class="_ _0"></span>址指<span class="_ _0"></span>出的<span class="_ _0"></span>某个<span class="_ _0"></span>长度的<span class="_ _0"></span>区</span></div><div class="t m0 xb h5 y2d ff2 fs0 fc0 sc0 ls0 ws0">域是空<span class="_ _0"></span>闲区；另<span class="_ _0"></span>一种是<span class="_ _0"></span><span class="fc2">“空表目”<span class="_ _0"></span>状态，<span class="_ _0"></span></span>表示表<span class="_ _0"></span>中对应的<span class="_ _0"></span>登记项目<span class="_ _0"></span>是空白（<span class="_ _0"></span>无效），可</div><div class="t m0 xb h5 y4 ff2 fs0 fc0 sc0 ls0 ws0">用<span class="_ _0"></span>来登<span class="_ _0"></span>记<span class="_ _0"></span>新<span class="_ _0"></span>的空<span class="_ _0"></span>闲<span class="_ _0"></span>区<span class="_ _0"></span>（例<span class="_ _0"></span>如<span class="_ _0"></span>，<span class="_ _0"></span>作<span class="_ _0"></span>业完<span class="_ _0"></span>成<span class="_ _0"></span>后<span class="_ _0"></span>，它<span class="_ _0"></span>所<span class="_ _0"></span>占<span class="_ _0"></span>的区<span class="_ _0"></span>域<span class="_ _0"></span>就<span class="_ _0"></span>成了<span class="_ _0"></span>空<span class="_ _0"></span>闲<span class="_ _0"></span>区，<span class="_ _0"></span>应<span class="_ _0"></span>找<span class="_ _0"></span>一<span class="_ _0"></span>个</div><div class="t m0 xb h5 y5 ff2 fs0 fc0 sc0 ls0 ws0">“空表<span class="_ _0"></span>目”栏登记<span class="_ _0"></span>归还区的<span class="_ _0"></span>起址和长<span class="_ _0"></span>度且修<span class="_ _0"></span><span class="ff5">改</span>状态）<span class="_ _0"></span>。由<span class="ff5">于</span>分<span class="_ _0"></span>区的个数<span class="_ _0"></span>不定，所<span class="_ _0"></span>以空闲</div><div class="t m0 xb h5 y6 ff2 fs0 fc0 sc0 ls0 ws0">区说明表中应有适量的状态为“空表目”的登记栏目，否则<span class="ff5">造</span>成表格“<span class="ff5">溢</span>出”无法登记。</div><div class="t m0 x1 h5 y7 ff1 fs0 fc0 sc0 ls0 ws0"> <span class="ff3"><span class="_ _0"></span><span class="ff2">、当<span class="_ _0"></span>有一个<span class="_ _0"></span>新作业<span class="_ _0"></span>要求<span class="_ _0"></span>装入主<span class="_ _0"></span>存时，<span class="_ _0"></span>必须<span class="_ _0"></span>查空闲区<span class="_ _0"></span>说明<span class="_ _0"></span>表，从<span class="_ _0"></span>中找出<span class="_ _0"></span>一个<span class="_ _0"></span>足够大<span class="_ _0"></span>的空闲</span></span></div><div class="t m0 x2 h5 y8 ff2 fs0 fc0 sc0 ls0 ws0">区。<span class="_ _0"></span>有时找<span class="_ _0"></span><span class="ff5">到</span>的<span class="_ _0"></span>空闲区<span class="_ _0"></span>可能大<span class="_ _0"></span><span class="ff5">于</span>作<span class="_ _0"></span>业需<span class="_ _0"></span>要量，这<span class="_ _0"></span>时应<span class="_ _0"></span>把<span class="ff5">原<span class="_ _0"></span></span>来的空<span class="_ _0"></span>闲区变<span class="_ _0"></span>成两<span class="_ _0"></span>部分：<span class="_ _0"></span>一</div><div class="t m0 x2 h5 y9 ff2 fs0 fc0 sc0 ls0 ws0">部分<span class="_ _0"></span>分给作<span class="_ _0"></span>业占<span class="_ _0"></span>用；另<span class="_ _0"></span>一部分<span class="_ _0"></span><span class="ff5">又</span>成<span class="_ _0"></span>为一<span class="_ _0"></span>个<span class="ff5">较</span>小<span class="_ _0"></span>的空闲<span class="_ _0"></span>区，<span class="_ _0"></span><span class="ff5">留</span>在空<span class="_ _0"></span>闲区表<span class="_ _0"></span>中。<span class="_ _0"></span>为了<span class="_ _0"></span><span class="ff5">尽</span>量</div><div class="t m0 x2 h5 ya ff5 fs0 fc0 sc0 ls0 ws0">减少<span class="_ _0"></span><span class="ff2">由</span>于<span class="ff2">分<span class="_ _0"></span>割</span>造<span class="_ _0"></span><span class="ff2">成的空<span class="_ _0"></span>闲区，<span class="_ _0"></span></span>尽<span class="ff2">可<span class="_ _0"></span>能分<span class="_ _0"></span>配</span>低<span class="ff2">地<span class="_ _0"></span>址部分<span class="_ _0"></span>的空<span class="_ _0"></span>闲区，<span class="_ _0"></span>而</span>尽<span class="_ _0"></span><span class="ff2">量</span>保<span class="ff2">存<span class="_ _0"></span>高地<span class="_ _0"></span>址部</span></div><div class="t m0 x2 h5 yb ff2 fs0 fc0 sc0 ls0 ws0">分有<span class="ff5">较</span>大的<span class="_ _0"></span><span class="ff1"> </span>连续空<span class="_ _0"></span>闲区域，以利<span class="ff5">于</span>大<span class="_ _0"></span><span class="ff5">型</span>作业的装入。为<span class="_ _0"></span><span class="ff5">此</span>，在空闲区说明<span class="_ _0"></span>表中，把<span class="ff5">每</span></div><div class="t m0 x2 h5 yc ff2 fs0 fc0 sc0 ls0 ws0">个空<span class="_ _0"></span>闲区按<span class="_ _0"></span>其地<span class="_ _0"></span>址<span class="ff5">顺</span>序<span class="_ _0"></span>从<span class="ff5">低<span class="_ _0"></span>到</span>高登<span class="_ _0"></span>记，<span class="_ _0"></span><span class="ff5">即每</span>个<span class="_ _0"></span>后<span class="ff5">继</span>的<span class="_ _0"></span>空闲<span class="_ _0"></span>区其起<span class="_ _0"></span>始地址<span class="_ _0"></span>总是<span class="_ _0"></span><span class="ff5">比前<span class="_ _0"></span></span>者大<span class="_ _0"></span>。</div><div class="t m0 x2 h5 yd ff2 fs0 fc0 sc0 ls0 ws0">为了方<span class="ff5">便</span>查找还可使表格“<span class="ff5">紧缩</span>”，总是<span class="ff5">让</span>“空表目”项<span class="ff5">留</span>在表格的后部。</div><div class="t m0 x1 h5 ye ff3 fs0 fc0 sc0 ls0 ws0"><span class="ff2">、采用最<span class="ff5">先</span>适应算法（<span class="ff5">顺</span>序分配算法）分配主存空间。</span></div><div class="t m0 x2 h5 y2e ff2 fs0 fc0 sc0 ls0 ws0">按<span class="ff5">照<span class="_ _0"></span></span>作业的<span class="_ _0"></span>需要<span class="_ _0"></span>量，查<span class="_ _0"></span>空闲区<span class="_ _0"></span>说明<span class="_ _0"></span>表，<span class="_ _0"></span><span class="ff5">顺</span>序查<span class="_ _0"></span>看登记<span class="_ _0"></span>栏，<span class="_ _0"></span>找<span class="ff5">到</span>第<span class="_ _0"></span>一个能<span class="_ _0"></span><span class="ff5">满</span>足<span class="_ _0"></span>要求<span class="_ _0"></span>的空</div><div class="t m0 xc h5 y2f ff2 fs0 fc0 sc0 ls0 ws0">闲区。当空闲区大<span class="ff5">于</span>需要量时，一部分用来装入作业，另一部分<span class="ff5">仍</span>为空闲区登记在空闲</div><div class="t m0 xc h5 y30 ff2 fs0 fc0 sc0 ls0 ws0">区说明表中。</div><div class="t m0 x2 h5 y31 ff2 fs0 fc0 sc0 ls0 ws0">由<span class="ff5">于<span class="_ _0"></span></span>本实验<span class="_ _0"></span>是模<span class="_ _0"></span>拟主存<span class="_ _0"></span>的分配<span class="_ _0"></span>，所<span class="_ _0"></span>以把主<span class="_ _0"></span>存区分<span class="_ _0"></span>配给作<span class="_ _0"></span>业后并<span class="_ _0"></span>不实<span class="_ _0"></span><span class="ff5">际启<span class="_ _0"></span></span>动装<span class="_ _0"></span>入程序<span class="_ _0"></span>装</div><div class="t m0 xd h5 y32 ff2 fs0 fc0 sc0 ls0 ws0">入作业，而用<span class="ff5">输</span>出“分配情况”来<span class="ff5">代替</span>。</div><div class="t m0 x1 h5 y33 ff1 fs0 fc0 sc0 ls0 ws0">4<span class="ff2">、当一个作业执行完成撤离时，作业所占的分区应该归还给系统，归还的分区如<span class="ff5">果</span>与其它</span></div><div class="t m0 xd h5 y34 ff2 fs0 fc0 sc0 ls0 ws0">空闲<span class="_ _0"></span>区<span class="ff5">相邻<span class="_ _0"></span></span>，则<span class="_ _0"></span>应合成<span class="_ _0"></span>一个<span class="_ _0"></span><span class="ff5">较</span>大的<span class="_ _0"></span>空闲<span class="_ _0"></span>区，登记<span class="_ _0"></span>在空<span class="_ _0"></span>闲区说<span class="_ _0"></span>明表中<span class="_ _0"></span>。例<span class="_ _0"></span>如，在<span class="_ _0"></span><span class="ff5">上<span class="_ _0"></span>述</span>中<span class="ff5">列</span></div><div class="t m0 xd h5 y35 ff5 fs0 fc0 sc0 ls0 ws0">举<span class="ff2">的<span class="_ _0"></span><span class="ff1"> <span class="_ _0"></span> <span class="_ _0"></span></span>情<span class="_ _0"></span>况下，<span class="_ _0"></span>如<span class="_ _0"></span></span>果<span class="ff2">作<span class="_ _0"></span>业<span class="_ _8"> </span><span class="ff1">2<span class="_ _9"> </span></span>撤离<span class="_ _0"></span>，归<span class="_ _0"></span>还所<span class="_ _0"></span>占主<span class="_ _0"></span>存区<span class="_ _0"></span>域时<span class="_ _0"></span>，应<span class="_ _0"></span>与<span class="_ _0"></span></span>上<span class="ff2">、<span class="_ _0"></span>下</span>相<span class="_ _0"></span>邻<span class="ff2">的<span class="_ _0"></span>空闲<span class="_ _0"></span>区一<span class="_ _0"></span>起</span></div><div class="t m0 xd h5 y36 ff2 fs0 fc0 sc0 ls0 ws0">合成一个大的空闲区登记在空闲区说明表中。</div><div class="t m0 x1 h4 y37 ff4 fs2 fc2 sc0 ls0 ws0">2)<span class="ff5 sc3">流<span class="ff2">程</span>图<span class="ff2">：<span class="fs0 fc1 sc2"> </span></span></span></div><div class="t m0 x1 h7 y38 ff3 fs0 fc0 sc0 ls0 ws0"><span class="_ _0"></span><span class="ff2 fs3">主存回收算法</span></div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626cab176ed7575b4d513dab/bg3.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h7 y39 ff3 fs0 fc0 sc0 ls0 ws0"><span class="_ _0"></span><span class="ff2 fs3">首次适应分配模拟算法</span></div><div class="t m0 x1 h4 y3a ff6 fs2 fc0 sc0 ls0 ws0">3)<span class="ff2 sc1">源程序</span>:</div><div class="t m0 x1 h7 y3b ff3 fs0 fc0 sc0 ls0 ws0"></div><div class="t m0 x1 h7 y3c ff3 fs0 fc0 sc0 ls0 ws0"> </div><div class="t m0 x1 h7 y3d ff3 fs0 fc0 sc0 ls0 ws0">!"#$$</div><div class="t m0 x1 h7 y3e ff3 fs0 fc0 sc0 ls0 ws0">!% &'()&'(*)+&,-&'())</div><div class="t m0 x1 h7 y3f ff3 fs0 fc0 sc0 ls0 ws0">! &'()&'(*)+&,-&'())</div><div class="t m0 x1 h5 y40 ff3 fs0 fc0 sc0 ls0 ws0">++.//<span class="ff2">要调度的作业数和要回收的区域数</span></div><div class="t m0 x1 h5 y41 ff3 fs0 fc0 sc0 ls0 ws0">+0.//<span class="ff5">已<span class="ff2">分配作业数</span></span></div><div class="t m0 x1 h5 y42 ff3 fs0 fc0 sc0 ls0 ws0">1.//<span class="ff2">分配成<span class="ff5">功标志</span></span></div><div class="t m0 x1 h5 y43 ff3 fs0 fc0 sc0 ls0 ws0">(2.//<span class="_ _0"></span><span class="ff2">回收区域存在<span class="ff5">上邻</span>和下<span class="ff5">邻</span>的<span class="ff5">标志</span></span></div><div class="t m0 x1 h7 y44 ff3 fs0 fc0 sc0 ls0 ws0">0.</div><div class="t m0 x1 h7 y45 ff4 fs0 fc3 sc0 ls0 ws0">struct jcb<span class="ff3 fc0">3</span></div><div class="t m0 x2 h7 y46 ff3 fs0 fc0 sc0 ls0 ws0">4+56.</div><div class="t m0 x2 h7 y47 ff3 fs0 fc0 sc0 ls0 ws0">4.</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
存储管理
