用java开发一个Hello Word系统内核

1 最简单的Hello World系统内核实现

java代码如下，代码就不做过多解释了，直接看就可以了：

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;


public class OperatingSystem {
    private int[] imgContent = new int[]{
        0xeb,0x4e,0x90,0x48,0x45,0x4c,0x4c,0x4f,0x49,0x50,0x4c,0x00,0x02,0x01,0x01,0x00,0x02,0xe0,
        0x00,0x40,0x0b,0xf0,0x09,0x00,0x12,0x00,0x02,0x00,0x00,0x00,0x00,0x00,0x40,0x0b,0x00,0x00,0x00,0x00,0x29,
        0xff,0xff,0xff,0xff,0x48,0x45,0x4c,0x4c,0x4f,0x2d,0x4f,0x53,0x20,0x20,0x20,0x46,0x41,0x54,0x31,0x32,
        0x20,0x20,0x20,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xb8,0x00,0x00,0x8e,
        0xd0,0xbc,0x00,0x7c,0x8e,0xd8,0x8e,0xc0,0xbe,0x74,0x7c,0x8a,
        0x04,0x83,0xc6,0x01,0x3c,0x00,0x74,0x09,0xb4,0x0e,0xbb,0x0f,0x00,0xcd,0x10,0xeb,0xee,0xf4,0xeb,0xfd
    };

    private ArrayList<Integer> imgByteToWrite = new ArrayList<Integer>();



    public OperatingSystem(String s) {
        for (int i = 0; i < imgContent.length; i++) {
            imgByteToWrite.add(imgContent[i]);
        }

        imgByteToWrite.add(0x0a);	// 换行符 \n
        imgByteToWrite.add(0x0a);	// 换行符 \n
        for (int j = 0; j < s.length(); j++) {
            imgByteToWrite.add((int)s.charAt(j));
        }
        imgByteToWrite.add(0x0a);	// 换行符 \n

        // 这里一直从现有代码之后到510字节的所有内容都填充为0
        int len = 0x1fe;
        int curSize = imgByteToWrite.size();
        for (int k = 0; k < len - curSize; k++) {
            imgByteToWrite.add(0);
        }

        // 第511、512字节为磁盘主引导扇区的有效标志，必须为0x55、0xaa
        // 0x1fe-0x1f: 0x55, 0xaa
        // 0x200-0x203: f0 ff  ff
        imgByteToWrite.add(0x55);
        imgByteToWrite.add(0xaa);
        imgByteToWrite.add(0xf0);
        imgByteToWrite.add(0xff);
        imgByteToWrite.add(0xff);

		// 总共1.44MB大小
        len = 0x168000;
        curSize = imgByteToWrite.size();
        for (int l = 0; l < len - curSize; l++) {
            imgByteToWrite.add(0);
        }

    }

    public void makeFllopy()   {
        try {
            DataOutputStream out = new DataOutputStream(new FileOutputStream("system.img"));
            for (int i = 0; i < imgByteToWrite.size(); i++) {
                out.writeByte(imgByteToWrite.get(i).byteValue());
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {
        OperatingSystem op = new OperatingSystem("hello, this is my first line of my operating system code");
        op.makeFllopy();
    }
}

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2 使用VirtualBox创建虚拟机并加载上述生成的软盘文件

2.1 创建虚拟机

创建时，需要注意类型和版本的选择：

一路下一步，这里不添加虚拟硬盘：

然后就创建完成。

我们需要设置虚拟机从软驱启动，点击设置，设置方式如下：

然后添加软驱：

然后选择对应的虚拟软盘即可：

2.2 加载软盘中的内核

点击启动虚拟机，将出现如下界面，大功告成：

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参考资料：

1. Linux操作系统, 构建自己的内核