first commit

2024-09-05 13:31:02 +08:00
commit 5f1b6a7b06
56 changed files with 5649 additions and 0 deletions
--- a/Lab/Lab5/code/main.c
+++ b/Lab/Lab5/code/main.c
@@ -0,0 +1,237 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define REQUEST_LENGTH 100
+#define DISK_TRACKS 200
+
+double fcfs(int* requestArray, int requestLength, int headStart, int* outputArray);
+double sstf(int* requestArray, int requestLength, int headStart, int* outputArray);
+double scan(int* requestArray, int requestLength, int headStart, int* outputArray);
+double cscan(int* requestArray, int requestLength, int headStart, int* outputArray);
+double fscan(int* requestArray1, int requestLength1, int* requestArray2, int requestLength2, int headStart, int *outputArray);
+
+
+// 生成随机磁道访问序列
+void generateRandomSequence(int* sequence, int length) {
+    for (int i = 0; i < length; i++) {
+        sequence[i] = rand() % DISK_TRACKS;
+    }
+}
+
+// 打印磁道访问顺序及平均寻道数
+void printResults(const char* algorithmName, int* accessSequence, int length, double avgSeek) {
+    printf("%s Algorithm:\n", algorithmName);
+    printf("Visit Order: ");
+    for (int i = 0; i < length; i++) {
+        printf("%d ", accessSequence[i]);
+    }
+    printf("\nAvg Seek Times: %.2f\n\n", avgSeek);
+}
+
+int main() {
+    int requestSequence[REQUEST_LENGTH];
+    int *outputSequence[REQUEST_LENGTH];
+    int tempSequence[REQUEST_LENGTH];
+    double avgSeek;
+    int headStart = 50; // 假设的起始磁头位置
+
+    // 生成随机磁道访问序列
+    srand((unsigned)time(NULL));
+    generateRandomSequence(requestSequence, REQUEST_LENGTH);
+
+    // 测试 FCFS 算法
+    memcpy(tempSequence, requestSequence, sizeof(requestSequence));
+    avgSeek = fcfs(tempSequence, REQUEST_LENGTH, headStart, outputSequence);
+    printResults("FCFS", outputSequence, REQUEST_LENGTH, avgSeek);
+
+    // 测试 SSTF 算法
+    memcpy(tempSequence, requestSequence, sizeof(requestSequence));
+    avgSeek = sstf(tempSequence, REQUEST_LENGTH, headStart, outputSequence);
+    printResults("SSTF", outputSequence, REQUEST_LENGTH, avgSeek);
+
+    // 测试 SCAN 算法
+    memcpy(tempSequence, requestSequence, sizeof(requestSequence));
+    avgSeek = scan(tempSequence, REQUEST_LENGTH, headStart, outputSequence);
+    printResults("SCAN", outputSequence, REQUEST_LENGTH, avgSeek);
+
+    // 测试 CSCAN 算法
+    memcpy(tempSequence, requestSequence, sizeof(requestSequence));
+    avgSeek = cscan(tempSequence, REQUEST_LENGTH, headStart, outputSequence);
+    printResults("CSCAN", outputSequence, REQUEST_LENGTH, avgSeek);
+
+    // 测试 FSCAN 算法
+    // 注意：FSCAN需要两个队列，但为简化，在这里使用相同的队列两次
+    memcpy(tempSequence, requestSequence, sizeof(requestSequence));
+    avgSeek = fscan(requestSequence, REQUEST_LENGTH / 2, requestSequence + REQUEST_LENGTH / 2, REQUEST_LENGTH / 2, headStart, outputSequence);
+    printResults("FSCAN", outputSequence, REQUEST_LENGTH, avgSeek);
+
+    return 0;
+}
+
+
+double fcfs(int* requestArray, int requestLength, int headStart, int* outputArray) {
+    int totalMovement = 0;
+    int currentPosition = headStart;
+
+    for (int i = 0; i < requestLength; i++) {
+        // 计算当前请求和磁头位置之间的距离
+        totalMovement += abs(requestArray[i] - currentPosition);
+        // 移动磁头到当前请求位置
+        currentPosition = requestArray[i];
+        // 记录移动过程
+        outputArray[i] = currentPosition;
+    }
+
+    // 计算平均寻道数
+    return (double)totalMovement / requestLength;
+}
+
+double sstf(int* requestArray, int requestLength, int headStart, int* outputArray) {
+    int totalSeekCount = 0;
+    int processedCount = 0;
+    int currentPosition = headStart;
+    int minDistance, closestIndex;
+
+    // 初始化一个数组来标记已处理的请求
+    int processed[REQUEST_LENGTH] = {0};
+    for (int i = 0; i < requestLength; i++) processed[i] = 0;
+
+    while (processedCount < requestLength) {
+        minDistance = 2147483647;
+
+        // 找到最近的请求
+        for (int i = 0; i < requestLength; i++) {
+            if (!processed[i] && abs(requestArray[i] - currentPosition) < minDistance) {
+                minDistance = abs(requestArray[i] - currentPosition);
+                closestIndex = i;
+            }
+        }
+
+        // 处理这个请求
+        totalSeekCount += minDistance;
+        currentPosition = requestArray[closestIndex];
+        processed[closestIndex] = 1;
+        outputArray[processedCount++] = currentPosition;
+    }
+
+    // 计算平均寻道数
+    return (double)totalSeekCount / requestLength;
+}
+
+int compare(const void *a, const void *b) {
+    return (*(int*)a - *(int*)b);
+}
+
+double scan(int* requestArray, int requestLength, int headStart, int* outputArray) {
+    int totalSeekCount = 0;
+    int processedCount = 0;
+    int currentPosition = headStart;
+
+    // 使用qsort进行排序
+    qsort(requestArray, requestLength, sizeof(int), compare);
+
+    // 找到起始位置最近的请求
+    int startIndex;
+    for (startIndex = 0; startIndex < requestLength; startIndex++) {
+        if (requestArray[startIndex] >= headStart) break;
+    }
+
+    // 先向上移动
+    for (int i = startIndex; i < requestLength; i++) {
+        totalSeekCount += abs(currentPosition - requestArray[i]);
+        currentPosition = requestArray[i];
+        outputArray[processedCount++] = currentPosition;
+    }
+
+    // 然后向下移动
+    for (int i = startIndex - 1; i >= 0; i--) {
+        totalSeekCount += abs(currentPosition - requestArray[i]);
+        currentPosition = requestArray[i];
+        outputArray[processedCount++] = currentPosition;
+    }
+
+    // 计算平均寻道数
+    return (double)totalSeekCount / requestLength;
+}
+
+double cscan(int* requestArray, int requestLength, int headStart, int* outputArray) {
+    int totalSeekCount = 0;
+    int processedCount = 0;
+    int currentPosition = headStart;
+
+    // 使用 qsort 进行排序
+    qsort(requestArray, requestLength, sizeof(int), compare);
+
+    // 找到起始位置最近的请求索引
+    int startIndex;
+    for (startIndex = 0; startIndex < requestLength; startIndex++) {
+        if (requestArray[startIndex] >= headStart) break;
+    }
+
+    // 先处理磁头上方的请求
+    for (int i = startIndex; i < requestLength; i++) {
+        totalSeekCount += abs(currentPosition - requestArray[i]);
+        currentPosition = requestArray[i];
+        outputArray[processedCount++] = currentPosition;
+    }
+
+    // 如果有必要，跳转到最低请求
+    if (startIndex != 0) {
+        totalSeekCount += abs(currentPosition - requestArray[0]);
+        currentPosition = requestArray[0];
+    }
+
+    // 然后处理磁头下方的请求
+    for (int i = 0; i < startIndex; i++) {
+        totalSeekCount += abs(currentPosition - requestArray[i]);
+        currentPosition = requestArray[i];
+        outputArray[processedCount++] = currentPosition;
+    }
+
+    // 计算平均寻道数
+    return (double)totalSeekCount / requestLength;
+}
+
+void processQueue(int* queue, int length, int* currentPosition, int* totalSeekCount, int* outputArray, int* processedCount) {
+    // 对队列进行排序
+    qsort(queue, length, sizeof(int), compare);
+
+    // 找到最接近当前磁头位置的请求
+    int i = 0;
+    while (i < length && queue[i] < *currentPosition) {
+        i++;
+    }
+
+    // 先处理磁头位置之后（更高磁道号）的请求
+    for (int j = i; j < length; j++) {
+        *totalSeekCount += abs(*currentPosition - queue[j]);
+        *currentPosition = queue[j];
+        outputArray[(*processedCount)++] = queue[j];
+    }
+
+    // 再处理磁头位置之前（更低磁道号）的请求
+    for (int j = i - 1; j >= 0; j--) {
+        *totalSeekCount += abs(*currentPosition - queue[j]);
+        *currentPosition = queue[j];
+        outputArray[(*processedCount)++] = queue[j];
+    }
+}
+
+double fscan(int* requestArray1, int requestLength1, int* requestArray2, int requestLength2, int headStart, int* outputArray) {
+    int totalSeekCount = 0;
+    int currentPosition = headStart;
+    int processedCount = 0;
+
+    // 处理第一个队列
+    processQueue(requestArray1, requestLength1, &currentPosition, &totalSeekCount, outputArray, &processedCount);
+
+    // 处理第二个队列
+    processQueue(requestArray2, requestLength2, &currentPosition, &totalSeekCount, outputArray + requestLength1, &processedCount);
+
+    // 计算平均寻道数
+    return (double)totalSeekCount / (requestLength1 + requestLength2);
+}
+
+