计算机操作磁盘调度算法C++

感谢您的提问。关于计算机操作磁盘调度算法C，我可以为您提供一些基本的知识和介绍。磁盘调度算法是操作系统中的一种重要算法，主要是通过对磁盘I/O请求进行排序，从而提高磁盘访问效率。常见的磁盘调度算法有FIFO、SCAN、C-SCAN、LOOK、C-LOOK等。C-SCAN算法比较适合处理大量的连续块请求，可以优化磁盘的寻道时间和旋转延迟，从而提高磁盘I/O效率。相信这些信息可以帮助您更好地了解磁盘调度算法C。如果您有其他问题，欢迎随时提出。

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磁盘调度算法c++

磁盘调度算法是操作系统中的一种重要算法，用于调度硬盘上的读写请求。常见的磁盘调度算法有FCFS、SSTF、SCAN、C-SCAN等。以下是一个简单的磁盘调度算法的C++代码示例，仅供参考：

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

// 定义存储磁盘请求的结构体
struct Request {
    int track; // 磁道号
    int time; // 到达时间
};

// FCFS磁盘调度算法
void FCFS(vector<Request>& req, int start) {
    int curr = start; // 当前磁道号
    int total = 0; // 总移动距离
    for (int i = 0; i < req.size(); i++) {
        total += abs(curr - req[i].track);
        curr = req[i].track;
    }
    cout << "FCFS: " << total << endl;
}

// SSTF磁盘调度算法
void SSTF(vector<Request>& req, int start) {
    int curr = start;
    int total = 0;
    while (!req.empty()) {
        int idx = 0, min_dist = INT_MAX;
        for (int i = 0; i < req.size(); i++) {
            int dist = abs(curr - req[i].track);
            if (dist < min_dist) {
                idx = i;
                min_dist = dist;
            }
        }
        total += min_dist;
        curr = req[idx].track;
        req.erase(req.begin() + idx);
    }
    cout << "SSTF: " << total << endl;
}

// SCAN磁盘调度算法
void SCAN(vector<Request>& req, int start, int end) {
    int curr = start;
    int total = 0;
    vector<Request> left, right;
    for (int i = 0; i < req.size(); i++) {
        if (req[i].track < start) left.push_back(req[i]);
        else if (req[i].track > end) right.push_back(req[i]);
        else continue;
    }
    sort(left.begin(), left.end(), [](Request& a, Request& b) { return a.track > b.track; });
    sort(right.begin(), right.end(), [](Request& a, Request& b) { return a.track < b.track; });
    for (int i = 0; i < left.size(); i++) {
        total += abs(curr - left[i].track);
        curr = left[i].track;
    }
    total += end - start;
    curr = end;
    for (int i = 0; i < right.size(); i++) {
        total += abs(curr - right[i].track);
        curr = right[i].track;
    }
    cout << "SCAN: " << total << endl;
}

// C-SCAN磁盘调度算法
void CSCAN(vector<Request>& req, int start, int end) {
    int curr = start;
    int total = 0;
    vector<Request> left, right;
    for (int i = 0; i < req.size(); i++) {
        if (req[i].track < start) left.push_back(req[i]);
        else if (req[i].track > end) right.push_back(req[i]);
        else continue;
    }
    sort(left.begin(), left.end(), [](Request& a, Request& b) { return a.track > b.track; });
    sort(right.begin(), right.end(), [](Request& a, Request& b) { return a.track < b.track; });
    for (int i = 0; i < left.size(); i++) {
        total += abs(curr - left[i].track);
        curr = left[i].track;
    }
    total += end - start;
    curr = end;
    for (int i = 0; i < right.size(); i++) {
        total += abs(curr - right[i].track);
        curr = right[i].track;
    }
    curr = start;
    for (int i = 0; i < left.size(); i++) {
        total += abs(curr - left[i].track);
        curr = left[i].track;
    }
    cout << "C-SCAN: " << total << endl;
}

int main() {
    vector<Request> req { {55, 0}, {58, 3}, {39, 8}, {18, 13}, {90, 17}, {160, 22}, {150, 28}, {38, 39} };
    FCFS(req, 50);
    SSTF(req, 50);
    SCAN(req, 50, 200);
    CSCAN(req, 50, 200);
    return 0;
}

以上代码实现了四种磁盘调度算法：FCFS、SSTF、SCAN、C-SCAN。其中，FCFS算法按照请求的先后顺序依次处理，SSTF算法每次选择离当前磁道号最近的请求，SCAN算法按照磁道号方向依次处理，C-SCAN算法则是在SCAN算法的基础上，将磁道号从尾部到头部再处理一遍。

sstf磁盘调度算法 C++

下面是一个简单的 C++ 实现 Scheduling SSTF 磁盘调度算法的示例代码：

#include<iostream>
#include<cstdlib>
using namespace std;

int main()
{
    int queue[20], q_size, head, seek = 0, max, diff;
    float avg;

    cout << "Enter the size of queue: ";
    cin >> q_size;

    cout << "Enter queue: ";
    for(int i = 1; i <= q_size; i++)
    {
        cin >> queue[i];
    }

    cout << "Enter initial head position: ";
    cin >> head;

    queue[0] = head;

    for(int j = 0; j <= q_size-1; j++)
    {
        diff = abs(queue[j+1] - queue[j]);
        seek += diff;
        cout << "Move from " << queue[j] << " to " << queue[j+1] << " with seek " << diff << endl;
    }

    cout << "\nTotal seek time = " << seek << endl;
    avg = seek/(float)q_size;
    cout << "Average seek time = " << avg << endl;

    return 0;
}

该程序首先要求用户输入磁盘队列的大小和初始磁头位置，然后接受队列中的元素。程序使用循环来计算磁头移动次数，并输出每一步的移动和寻道距离。最后，程序计算总寻道时间和平均寻道时间，并将其打印到标准输出。

注意，这只是一个简单的示例程序，它假设输入是正确的，并且没有进行错误检查。实际上，当实现磁盘调度算法时，必须考虑到更多的因素。