操作系统实验四存储管理.doc

集美大学计算机工程学院实验报告课程名称：操作系统班级：计算1014指导教师：李传目姓名：林升仁实验项目编号：实验四学号：2010810116实验项目名称：存储管理实验成绩：一、目的理解动态异长存储分区资源管理，掌握所需数据结构和管理程序，了解各种存储分配算法的优点和缺点。二、实验内容与设计思想分析UNIX最先适应(FF)存储分配算法，即map数据结构、存储分配函数malloc()和存储释放函数mfree()，找出与算法有关的成分。 修改上述与算法有关的成分，使其分别体现BF分配原则和WF分配原则。 三、实验使用环境Red Hat Enterprise linux54、 实验结果源程序：/* * Copyright (C) 2004 by root * * rootsimplymepis * * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * * (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * GNU General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this program; if not, write to the * * Free Software Foundation, Inc., * * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * */#ifdef HAVE_CONFIG_H#include #endif#include #include #define MAPSIZE 116struct map /存储资源表结构 /* char *m_size; char *m_addr; */ int m_addr; int m_size;struct map mapMAPSIZE; /存储资源表int FF_malloc(struct map *mp,int size) /存储分配函数 register int a,s; register struct map *bp,*bpp; for(bp = mp; bp-m_size; bp+) if (bp-m_size = size) a = bp-m_addr; s = bp-m_size; for(bpp = bp; bpp-m_size; bpp+)/最先适应 if(bpp-m_size = size & bpp-m_addrm_addr; s = bpp-m_size; bp = bpp; bp-m_addr += size; if (bp-m_size -=size) = 0) do bp+; (bp-1)-m_addr = bp-m_addr; while(bp-1)-m_size = bp-m_size); return(a); return(-1);void mfree(struct map *mp,int aa,int size) /存储释放函数 register struct map *bp; register int t; register int a; a = aa; for(bp = mp; bp-m_addrm_size != 0; bp+) ; if(bpmp & (bp-1)-m_addr+(bp-1)-m_size=a) /与前合并 (bp-1)-m_size += size; if (a+size = bp-m_addr) /前后合并 (bp-1)-m_size += bp-m_size; while (bp-m_size) bp+; (bp-1)-m_addr = bp-m_addr; (bp-1)-m_size = bp-m_size; else if (a+size = bp-m_addr & bp-m_size) /与后合并 bp-m_addr -= size; bp-m_size += size; else if (size) do /无合并 t = bp-m_addr; bp-m_addr = a; a = t; t = bp-m_size; bp-m_size = size; bp+; while (size = t); void init() struct map *bp; int addr,size; int i=0; bp=map; printf(Please input starting addr and total size:); scanf(%d,%d,&addr,&size); bp-m_addr=addr; bp-m_size=size; (+bp)-m_size=0; /表尾void show_map() int i=0; system(clear); /调用清屏命令 struct map *bp; bp=map; printf(nCurrent memory map.n); printf(AddressttSizen); while(bp-m_size!=0) printf(n,bp-m_addr,bp-m_size);bp+; printf(n);main() int a,s; int c; int i; init(); do /显示存储分配表 show_map(); printf(Please input, 1 for request,2 for release, 0 for exit:); scanf(%d,&c); switch(c) case 1: printf(Please input size:); scanf(%d, &s); if(a=FF_malloc(map,s)=-1) /call malloc printf(request cant be satisfiedn); else printf(alloc memory at address:%d,size:%dn,a,s); break; case 2: printf(Please input addr and size:); scanf(%d,%d,&a,&s); mfree(map,a,s); break; case 0: exit(0); while(1);运行结果：5、 实验分析上述算法沿用了UNIX系统所采用的数据结构，存储分配表中空闲区按m_addr递增排列，对于任意请求，需要由表头查到表尾才能确定最佳（最坏）分配区域。为提高存储分配时的查找速度，有人将表中空闲区按m_size递增（递减）排列，这样分配时取第一个长度能满足的表项即可。采用这种组织方式，不仅分配后剩余部分在表中的位置可能发生变化，而且需对释放函数进行较大的修改，试给出对应的算法 对于Lin