磁盤驅(qū)動調(diào)度算法的模擬(共13頁)

1、精選優(yōu)質(zhì)文檔-傾情為你奉上一        編寫目的熟悉磁盤的結(jié)構(gòu)以及磁盤的驅(qū)動調(diào)度算法的模擬，編程實現(xiàn)簡單常用的磁盤驅(qū)動調(diào)度算法先來先服務(wù)（FIFO）、電梯調(diào)度算法、最短尋找時間優(yōu)先算法、掃描（雙向掃描）算法、單向掃描（循環(huán)掃描）算法等。編程只需實現(xiàn)兩個算法。題目可以選取教材或習(xí)題中的相關(guān)編程實例。編程語言建議采用c/c+或Java。模擬程序鼓勵采用隨機數(shù)技術(shù)、動態(tài)空間分配技術(shù)，有條件的最好能用圖形界面展現(xiàn)甚至用動畫模擬。實驗性質(zhì)：驗證型。二      

2、    課程設(shè)計內(nèi)容1）掌握使用一門語言進行磁盤驅(qū)動調(diào)度算法的模擬；2）編寫程序?qū)⒋疟P驅(qū)動調(diào)度算法的過程和結(jié)果能以較簡明直觀的方式展現(xiàn)出來。三          設(shè)計、方法和步驟1. 設(shè)計磁盤驅(qū)動調(diào)度對磁盤的效率有重要影響。磁盤驅(qū)動調(diào)度算法的好壞直接影響輔助存儲器的效率，從而影響計算機系統(tǒng)的整體效率。常用的磁盤驅(qū)動調(diào)度算法有：最簡單的磁盤驅(qū)動調(diào)度算法是先入先出（FIFO）法。這種算法的實質(zhì)是，總是嚴格按時間順序?qū)Υ疟P請求予以處理。算法實現(xiàn)簡單、易于理解并且

3、相對公平，不會發(fā)生進程餓死現(xiàn)象。但該算法可能會移動的柱面數(shù)較多并且會經(jīng)常更換移動方向，效率有待提高。 最短尋找時間優(yōu)先算法：總是優(yōu)先處理最靠近的請求。該算法移動的柱面距離較小，但可能會經(jīng)常改變移動方向，并且可能會發(fā)生進程饑餓現(xiàn)象。 電梯調(diào)度：總是將一個方向上的請求全部處理完后，才改變方向繼續(xù)處理其他請求。掃描（雙向掃描）：總是從最外向最里進行掃描，然后在從最里向最外掃描。該算法與電梯調(diào)度算法的區(qū)別是電梯調(diào)度在沒有最外或最里的請求時不會移動到最外或最里柱面，二掃描算法總是移到最外、最里柱面。兩端的請求有優(yōu)先服被務(wù)的跡象。循環(huán)掃描（單向掃描）：從最外向最里進行柱面請求處理，到最里柱面后，直接跳到最

4、外柱面然后繼續(xù)向里進行處理。該算法與掃描算法的區(qū)別是，回來過程不處理請求，基于這樣的事實，因為里端剛被處理。 2. 設(shè)計方法1）使用流程圖描述演示程序的設(shè)計思想；2）選取c/c+、Java等計算機語言，編程調(diào)試，最終給出運行正確的程序。3. 程序步驟參考程序：1)      c/c+版的驅(qū)動調(diào)度算法電梯調(diào)度模擬程序#include <stdio.h>#include <stdlib.h>#include <string.h>#include <conio.h>typedef struct _pro

5、cchar name32; /*定義進程名稱*/int team; /*定義柱面號*/int ci; /*定義磁道面號*/int rec; /*定義記錄號*/struct _proc *prior;struct _proc *next;PROC; PROC *g_head=NULL,*g_curr=NULL,*local;int record=0;int yi=1;void init()PROC *p; /*初始化鏈表（初始I/O表）*/g_head = (PROC*)malloc(sizeof(PROC);g_head->next = NULL;g_head->prio

6、r = NULL;p = (PROC*)malloc(sizeof(PROC);strcpy(p->name, "P1");p->team=100;p->ci=10;p->rec=1;p->next = NULL;p->prior = g_head;g_head->next = p;g_curr=g_head->next;p = (PROC*)malloc(sizeof(PROC);strcpy(p->name, "P2");p->team=30;p->ci=5;p->rec=5;p

7、->next = NULL;p->prior = g_curr;g_curr->next = p;g_curr=p;p = (PROC*)malloc(sizeof(PROC);strcpy(p->name, "P3");p->team=40;p->ci=2;p->rec=4;p->next = NULL;p->prior = g_curr;g_curr->next = p;g_curr=p;p = (PROC*)malloc(sizeof(PROC);strcpy(p->name, "P4&quo

8、t;);p->team=85;p->ci=7;p->rec=3;p->next = NULL;p->prior = g_curr;g_curr->next = p;g_curr=p;p = (PROC*)malloc(sizeof(PROC);strcpy(p->name, "P5");p->team=60;p->ci=8;p->rec=4;p->next = NULL;p->prior = g_curr;g_curr->next = p;g_curr=g_head->next;local

9、= (PROC*)malloc(sizeof(PROC); /*選中進程*/strcpy(local->name, "P0");local->team=0;local->ci=0;local->rec=0;local->next=NULL;local->prior=NULL;void PrintInit() /*打印I/O表*/ PROC *t = g_head->next;printf("-/n");printf(" -I/O LIST-/n");printf(" process

10、team ci rec /n");while(t!=NULL)printf("%4s %8d %8d %5d/n", t->name, t->team, t->ci, t->rec ); t = t->next;printf("/n/nCurrent process is :/n");printf("-/n/n");printf(" process team ci rec /n");printf("%4s %8d %8d %5d/n", local->

11、;name, local->team, local->ci, local->rec );switch(yi)case 1:printf("current direction is UP/n");break;case 0:printf("current direction is down/n");break;void acceptreq() /*接受請求函數(shù)*/PROC *p;p = (PROC*)malloc(sizeof(PROC);printf("please input the information of the ne

12、w process/nprocess-name:/nprocess-team/nprocess-ci/nprocess-rec/n");printf("1.name/n");scanf("%s",p->name);printf("2.team 0-199/n");scanf("%d",&p->team); /*輸入請求進程信息*/printf("3.ci 0-19/n");scanf("%d",&p->ci);printf(&quo

13、t;4.rec 0-7/n");scanf("%d",&p->rec);getchar();g_curr=g_head; /*將此節(jié)點鏈入I/O請求表*/while(g_curr->next!=NULL)g_curr=g_curr->next;p->next=NULL;p->prior=g_curr;g_curr->next=p;g_curr=g_head->next;printf("NEW I/O LIST/n/n");PrintInit(); /*將新的I/O請求表輸出*/void qddd

14、() /*驅(qū)動調(diào)度函數(shù)*/PROC *out;int min;int max=g_head->next->team;if (g_head->next=NULL); /*若已全部調(diào)度，則空操作*/else switch (yi)case 1: min=g_head->next->team;out=g_head->next; /*選出最小的team進程，模擬啟動此進程*/strcpy(local->name,out->name);local->team=out->team;local->ci=out->ci;local->

15、;rec=out->rec;for (g_curr=g_head->next;g_curr!=NULL;g_curr=g_curr->next)if (g_curr->team > record) min = g_curr->team;break;for (g_curr=g_head->next;g_curr!=NULL;g_curr=g_curr->next)if (min>=g_curr->team&&g_curr->team>record)min=g_curr->team;out=g_curr;

16、strcpy(local->name,out->name);local->team=out->team;local->ci=out->ci;local->rec=out->rec;printf("/n-/n");printf("the process choosed :/n"); printf(" process team ci rec /n");printf("%4s %8d %8d %5d/n", out->name, out->team,

17、out->ci,out->rec ); record = local->team;printf("%d",record);for (g_curr=g_head->next;g_curr!=NULL;g_curr=g_curr->next)if (max<g_curr->team)max=g_curr->team;if(max=record)yi=0;record=1000;break; break;/*case 1*/case 0: /*case 1 的對稱過程*/max=g_head->next-&

18、gt;team;out=g_head->next; strcpy(local->name,out->name);local->team=out->team;local->ci=out->ci;local->rec=out->rec;for (g_curr=g_head->next;g_curr!=NULL;g_curr=g_curr->next)if (g_curr->team < record) max = g_curr->team;break;for (g_curr=g_head->next;g_cu

19、rr!=NULL;g_curr=g_curr->next)if (max<=g_curr->team&&g_curr->team<record)max=g_curr->team;out=g_curr;strcpy(local->name,out->name);local->team=out->team;local->ci=out->ci;local->rec=out->rec;printf("/n-/n");printf("the process choosed :

20、/n"); printf(" process team ci rec /n");printf("%4s %8d %8d %5d/n", out->name, out->team, out->ci,out->rec );min=g_head->next->team;for (g_curr=g_head->next;g_curr!=NULL;g_curr=g_curr->next)if (min>g_curr->team)min=g_curr->team;record =

21、local->team;if(min=record)yi=1;record=0;break; break;default : return -1;/*switch*/ if (out->next=NULL) /*將選中的進程從I/O請求表中刪除*/out->prior->next=NULL;free(out);elseout->prior->next=out->next;out->next->prior=out->prior;free(out);/*else*/ void acceptnum() /*通過

22、輸入01選擇驅(qū)動調(diào)度或是接受請求*/float num;char c;while(1)printf("-/n");printf("please input a number between 0 and 1/nnum<=0.5:accept request/nnum>0.5:qudong diaodu/n/nnum=2:I/O LIST/n/nnum=?/n");scanf("%f",&num);getchar();while(num<0|num>1)&&num!=2) /*過濾不合法數(shù)據(jù)

23、 注意：本程序其他輸入數(shù)據(jù)可能未過濾*/printf("number ERROR!Input again please!/nnum=?/n ");scanf("%f",&num);getchar();if(num>0.5&&num!=2) /*驅(qū)動調(diào)度*/if (g_head->next=NULL)printf("/n/n");printf("-/n");printf("I/O list is empty!/n"); /*請求表為空 無需調(diào)度*/elseprintf("qudong diaodu/n"); qddd(); /*調(diào)用函數(shù)進行調(diào)度*/else