C语言或者Java模拟Fat文件系统

具体要求如上，代码需要有详细解释，米少另聊，评论区加V,教学内容，需要源代码

帮你找到相关直连，可以看看，
http://www.doczj.com/doc/958727577-6.html

linux下可能方便一下； 使用fuse对接这些shell 操作命令；在VFS下实例FAT的磁盘格式，元数据信息组织，空闲空间管理，在superblock里添加文件系统信息，就可以正常查出来。

可能需要一两个人花点时间，如果是教学用，还不如拆分开让学生写。

我倒是有不少这样的资料和代码，都是开发操作系统之前收集和学习的

C语言编写的FAT16文件系统
如有帮助，望采纳

#include <stdio.h>  
#include <malloc.h>  
#include <string.h>  
#include <time.h>  
  
#define BLOCKSIZE 1024  // 磁盘块大小  
#define SIZE 1024000  // 虚拟磁盘空间大小  
#define END 65535  // FAT中的文件结束标志  
#define FREE 0  // FAT中盘块空闲标志  
#define ROOTBLOCKNUM 2  // 根目录区所占盘块数  
#define MAXOPENFILE 10  // 最多同时打开文件个数t  
#define MAXTEXT 10000  
  
/* 文件控制块 */  
typedef struct FCB  
{  
    char filename[8];  // 文件名  
    char exname[3];  // 文件扩展名  
    unsigned char attribute;  // 文件属性字段，值为0时表示目录文件，值为1时表示数据文件  
    unsigned short time;  // 文件创建时间  
    unsigned short date;  // 文件创建日期  
    unsigned short first;  // 文件起始盘块号  
    unsigned long length;  // 文件长度  
    char free;  // 表示目录项是否为空，若值为0，表示空，值为1，表示已分配  
}fcb;  
  
/* 文件分配表 */  
typedef struct FAT  
{  
    unsigned short id;  // 磁盘块的状态（空闲的，最后的，下一个）  
}fat;  
/* 用户打开文件表 */  
typedef struct USEROPEN  
{  
    char filename[8];  // 文件名  
    char exname[3];  // 文件扩展名  
    unsigned char attribute;  // 文件属性字段，值为0时表示目录文件，值为1时表示数据文件  
    unsigned short time;  // 文件创建时间  
    unsigned short date;  // 文件创建日期  
    unsigned short first;  // 文件起始盘块号  
    unsigned long length;  // 文件长度（对数据文件是字节数，对目录文件可以是目录项个数）  
    char free;  // 表示目录项是否为空，若值为0，表示空，值为1，表示已分配  
  
    unsigned short dirno;  // 相应打开文件的目录项在父目录文件中的盘块号  
    int diroff;  // 相应打开文件的目录项在父目录文件的dirno盘块中的目录项序号  
    char dir[80];  // 相应打开文件所在的目录名，这样方便快速检查出指定文件是否已经打开  
    int father;  // 父目录在打开文件表项的位置  
    int count;  // 读写指针在文件中的位置,文件的总字符数  
    char fcbstate;  // 是否修改了文件的FCB的内容，如果修改了置为1，否则为0  
    char topenfile;  // 表示该用户打开表项是否为空，若值为0，表示为空，否则表示已被某打开文件占据  
}useropen;  
  
/* 引导块 */  
typedef struct BLOCK0  
{  
    char magic[10];  // 文件系统魔数  
    char information[200];  // 存储一些描述信息，如磁盘块大小、磁盘块数量、最多打开文件数等  
    unsigned short root;  // 根目录文件的起始盘块号  
    unsigned char *startblock;  // 虚拟磁盘上数据区开始位置  
}block0;  
unsigned char *myvhard;  // 指向虚拟磁盘的起始地址  
useropen openfilelist[MAXOPENFILE];  // 用户打开文件表数组  
int curdir;  // 用户打开文件表中的当前目录所在打开文件表项的位置  
char currentdir[80];  // 记录当前目录的目录名（包括目录的路径）  
unsigned char* startp;  // 记录虚拟磁盘上数据区开始位置  
char myfilename[] = "myfilesys";//文件系统的文件名  
  
void startsys();  // 进入文件系统  
void my_format();  // 磁盘格式化  
void my_cd(char *dirname);  // 更改当前目录  
void my_mkdir(char *dirname);  // 创建子目录  
void my_rmdir(char *dirname);  // 删除子目录  
void my_ls();  // 显示目录  
void my_create (char *filename);  // 创建文件  
void my_rm(char *filename);  // 删除文件  
int my_open(char *filename);  // 打开文件  
int my_close(int fd);  // 关闭文件  
int my_write(int fd);  // 写文件  
int do_write(int fd, char *text, int len, char wstyle);  // 实际写文件  
int my_read (int fd, int len);  // 读文件  
int do_read (int fd, int len,char *text);  // 实际读文件  
void my_exitsys();  // 退出文件系统  
unsigned short findblock();  // 寻找空闲盘块  
int findopenfile();  // 寻找空闲文件表项  
void startsys()  
{  
    FILE *fp;  
    unsigned char buf[SIZE];  
    fcb *root;  
    int i;  
    myvhard = (unsigned char *)malloc(SIZE);//申请虚拟磁盘空间  
    memset(myvhard, 0, SIZE);//将myvhard中前SIZE个字节用 0 替换并返回 myvhard  
    if((fp = fopen(myfilename, "r")) != NULL)  
    {  
        fread(buf, SIZE, 1, fp);//将二进制文件读取到缓冲区  
        fclose(fp);//关闭打开的文件，缓冲区数据写入文件，释放系统提供文件资源  
        if(strcmp(((block0 *)buf)->magic, "10101010"))//判断开始的8个字节内容是否为文件系统魔数  
        {  
            printf("myfilesys is not exist,begin to creat the file...\n");  
            my_format();  
        }  
        else  
        {  
            for(i = 0; i < SIZE; i++)  
                myvhard[i] = buf[i];  
        }  
    }  
    else  
    {  
        printf("myfilesys is not exist,begin to creat the file...\n");  
        my_format();  
    }  
    root = (fcb *)(myvhard + 5 * BLOCKSIZE);  
    strcpy(openfilelist[0].filename, root->filename);  
    strcpy(openfilelist[0].exname, root->exname);  
    openfilelist[0].attribute = root->attribute;  
    openfilelist[0].time = root->time;  
    openfilelist[0].date = root->date;  
    openfilelist[0].first = root->first;  
    openfilelist[0].length = root->length;  
    openfilelist[0].free = root->free;  
    openfilelist[0].dirno = 5;  
    openfilelist[0].diroff = 0;  
    strcpy(openfilelist[0].dir, "\\root\\");  
    openfilelist[0].father = 0;  
    openfilelist[0].count = 0;  
    openfilelist[0].fcbstate = 0;  
    openfilelist[0].topenfile = 1;  
    for(i = 1; i < MAXOPENFILE; i++)  
        openfilelist[i].topenfile = 0;  
    curdir = 0;  
    strcpy(currentdir, "\\root\\");  
    startp = ((block0 *)myvhard)->startblock;  
}  
void my_format()  
{  
    FILE *fp;  
    fat *fat1, *fat2;  
    block0 *blk0;  
    time_t now;  
    struct tm *nowtime;  
    fcb *root;  
    int i;  
    blk0 = (block0 *)myvhard;  
    fat1 = (fat *)(myvhard + BLOCKSIZE);  
    fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);  
    root = (fcb *)(myvhard + 5 * BLOCKSIZE);  
    strcpy(blk0->magic, "10101010");  
    strcpy(blk0->information, "My FileSystem Ver 1.0 \n Blocksize=1KB Whole size=1000KB Blocknum=1000 RootBlocknum=2\n");  
    blk0->root = 5;  
    blk0->startblock = (unsigned char *)root;  
    for(i = 0; i < 5; i++)  
    {  
        fat1->id = END;  
        fat2->id = END;  
        fat1++;  
        fat2++;  
    }  
    fat1->id = 6;  
    fat2->id = 6;  
    fat1++;  
    fat2++;  
    fat1->id = END;  
    fat2->id = END;  
    fat1++;  
    fat2++;  
    for(i = 7; i < SIZE / BLOCKSIZE; i++)  
    {  
        fat1->id = FREE;  
        fat2->id = FREE;  
        fat1++;  
        fat2++;  
    }  
    now = time(NULL);  
    nowtime = localtime(&now);  
    strcpy(root->filename, ".");  
    strcpy(root->exname, "");  
    root->attribute = 0x28;  
    root->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;  
    root->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;  
    root->first = 5;  
    root->length = 2 * sizeof(fcb);  
    root->free = 1;  
    root++;  
    now = time(NULL);  
    nowtime = localtime(&now);  
    strcpy(root->filename, "..");  
    strcpy(root->exname, "");  
    root->attribute = 0x28;  
    root->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;  
    root->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;  
    root->first = 5;  
    root->length = 2 * sizeof(fcb);  
    root->free = 1;  
    fp = fopen(myfilename, "w");  
    fwrite(myvhard, SIZE, 1, fp);  
    fclose(fp);  
}  
void my_cd(char *dirname)  
{  
    char *dir;  
    int fd;  
    dir = strtok(dirname, "\\");//分解字符串为一组字符串。dirname为要分解的字符串，"\\"为分隔符字符串  
    if(strcmp(dir, ".") == 0)  
        return;  
    else if(strcmp(dir, "..") == 0)  
    {  
        if(curdir)  
            curdir = my_close(curdir);  
        return;  
    }  
    else if(strcmp(dir, "root") == 0)  
    {  
        while(curdir)  
            curdir = my_close(curdir);  
        dir = strtok(NULL, "\\");  
    }  
    while(dir)  
    {  
        fd = my_open(dir);  
        if(fd != -1)  
            curdir = fd;  
        else  
            return;  
        dir = strtok(NULL, "\\");  
    }  
}  
void my_mkdir(char *dirname)  
{  
    fcb *fcbptr;  
    fat *fat1, *fat2;  
    time_t now;  
    struct tm *nowtime;  
    char text[MAXTEXT];  
    unsigned short blkno;  
    int rbn, fd, i;  
    fat1 = (fat *)(myvhard + BLOCKSIZE);  
    fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);  
    openfilelist[curdir].count = 0;  
    rbn = do_read(curdir, openfilelist[curdir].length, text);  
    fcbptr = (fcb *)text;  
    for(i = 0; i < rbn / sizeof(fcb); i++)//在当前目录下找，是否有重名目录  
    {  
        if(strcmp(fcbptr->filename, dirname) == 0 && strcmp(fcbptr->exname, "") == 0)  
        {  
            printf("Error,the dirname is already exist!\n");  
            return;  
        }  
        fcbptr++;  
    }  
    fcbptr = (fcb *)text;  
    for(i = 0; i < rbn / sizeof(fcb); i++)  
    {  
        if(fcbptr->free == 0)  
            break;  
        fcbptr++;  
    }  
    blkno = findblock();//寻找空闲盘块  
    if(blkno == -1)  
        return;  
    (fat1 + blkno)->id = END;  
    (fat2 + blkno)->id = END;  
    now = time(NULL);  
    nowtime = localtime(&now);  
    strcpy(fcbptr->filename, dirname);  
    strcpy(fcbptr->exname, "");  
    fcbptr->attribute = 0x30;  
    fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;  
    fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;  
    fcbptr->first = blkno;  
    fcbptr->length = 2 * sizeof(fcb);  
    fcbptr->free = 1;  
    openfilelist[curdir].count = i * sizeof(fcb);  
    do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);  
  
    fd = my_open(dirname);//建立新目录的'.','..'目录  
    if(fd == -1)  
        return;  
    fcbptr = (fcb *)malloc(sizeof(fcb));  
    now = time(NULL);  
    nowtime = localtime(&now);  
    strcpy(fcbptr->filename, ".");  
    strcpy(fcbptr->exname, "");  
    fcbptr->attribute = 0x28;  
    fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;  
    fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;  
    fcbptr->first = blkno;  
    fcbptr->length = 2 * sizeof(fcb);  
    fcbptr->free = 1;  
    do_write(fd, (char *)fcbptr, sizeof(fcb), 2);  
    now = time(NULL);  
    nowtime = localtime(&now);  
    strcpy(fcbptr->filename, "..");  
    strcpy(fcbptr->exname, "");  
    fcbptr->attribute = 0x28;  
    fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;  
    fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;  
    fcbptr->first = blkno;  
    fcbptr->length = 2 * sizeof(fcb);  
    fcbptr->free = 1;  
    do_write(fd, (char *)fcbptr, sizeof(fcb), 2);  
    free(fcbptr);  
    my_close(fd);  
  
    fcbptr = (fcb *)text;  
    fcbptr->length = openfilelist[curdir].length;  
    openfilelist[curdir].count = 0;  
    do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);  
    openfilelist[curdir].fcbstate = 1;  
}  
  
void my_rmdir(char *dirname)  
{  
    fcb *fcbptr,*fcbptr2;  
    fat *fat1, *fat2, *fatptr1, *fatptr2;  
    char text[MAXTEXT], text2[MAXTEXT];  
    unsigned short blkno;  
    int rbn, rbn2, fd, i, j;  
    fat1 = (fat *)(myvhard + BLOCKSIZE);  
    fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);  
    if(strcmp(dirname, ".") == 0 || strcmp(dirname, "..") == 0)  
    {  
        printf("Error,can't remove this directory.\n");  
        return;  
    }  
    openfilelist[curdir].count = 0;  
    rbn = do_read(curdir, openfilelist[curdir].length, text);  
    fcbptr = (fcb *)text;  
    for(i = 0; i < rbn / sizeof(fcb); i++)//查找要删除的目录  
    {  
        if(strcmp(fcbptr->filename, dirname) == 0 && strcmp(fcbptr->exname, "") == 0)  
            break;  
        fcbptr++;  
    }  
    if(i == rbn / sizeof(fcb))  
    {  
        printf("Error,the directory is not exist.\n");  
        return;  
    }  
    fd = my_open(dirname);  
    rbn2 = do_read(fd, openfilelist[fd].length, text2);  
    fcbptr2 = (fcb *)text2;  
    for(j = 0; j < rbn2 / sizeof(fcb); j++)//判断要删除目录是否为空  
    {  
        if(strcmp(fcbptr2->filename, ".") && strcmp(fcbptr2->filename, "..") && strcmp(fcbptr2->filename, ""))  
        {  
            my_close(fd);  
            printf("Error,the directory is not empty.\n");  
            return;  
        }  
        fcbptr2++;  
    }  
    blkno = openfilelist[fd].first;  
    while(blkno != END)  
    {  
        fatptr1 = fat1 + blkno;  
        fatptr2 = fat2 + blkno;  
        blkno = fatptr1->id;  
        fatptr1->id = FREE;  
        fatptr2->id = FREE;  
    }  
    my_close(fd);  
    strcpy(fcbptr->filename, "");  
    fcbptr->free = 0;  
    openfilelist[curdir].count = i * sizeof(fcb);  
    do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);  
    openfilelist[curdir].fcbstate = 1;  
}  
void my_ls()  
{  
    fcb *fcbptr;  
    char text[MAXTEXT];  
    int rbn, i;  
    openfilelist[curdir].count = 0;  
    rbn = do_read(curdir, openfilelist[curdir].length, text);  
    fcbptr = (fcb *)text;  
    for(i = 0; i < rbn / sizeof(fcb); i++)  
    {  
        if(fcbptr->free)  
        {  
            if(fcbptr->attribute & 0x20)  
                printf("%s\\\t\t<DIR>\t\t%d/%d/%d\t%02d:%02d:%02d\n", fcbptr->filename, (fcbptr->date >> 9) + 1980, (fcbptr->date >> 5) & 0x000f, fcbptr->date & 0x001f, fcbptr->time >> 11, (fcbptr->time >> 5) & 0x003f, fcbptr->time & 0x001f * 2);  
            else  
                printf("%s.%s\t\t%dB\t\t%d/%d/%d\t%02d:%02d:%02d\t\n", fcbptr->filename, fcbptr->exname, (int)(fcbptr->length), (fcbptr->date >> 9) + 1980, (fcbptr->date >> 5) & 0x000f, fcbptr->date & 0x1f, fcbptr->time >> 11, (fcbptr->time >> 5) & 0x3f, fcbptr->time & 0x1f * 2);  
        }  
        fcbptr++;  
    }  
}  
void my_create(char *filename)  
{  
    fcb *fcbptr;  
    fat *fat1, *fat2;  
    char *fname, *exname, text[MAXTEXT];  
    unsigned short blkno;  
    int rbn, i;  
    time_t now;  
    struct tm *nowtime;  
    fat1 = (fat *)(myvhard + BLOCKSIZE);  
    fat2 = (fat *)(myvhard + BLOCKSIZE);  
    fname = strtok(filename, ".");  
    exname = strtok(NULL, ".");  
    if(strcmp(fname, "") == 0)  
    {  
        printf("Error,creating file must have a right name.\n");  
        return;  
    }  
    if(!exname)  
    {  
        printf("Error,creating file must have a extern name.\n");  
        return;  
    }  
    openfilelist[curdir].count = 0;  
    rbn = do_read(curdir, openfilelist[curdir].length, text);  
    fcbptr = (fcb *)text;  
    for(i = 0; i < rbn / sizeof(fcb); i++)  
    {  
        if(strcmp(fcbptr->filename, fname) == 0 && strcmp(fcbptr->exname, exname) == 0)  
        {  
            printf("Error,the filename is already exist!\n");  
            return;  
        }  
        fcbptr++;  
    }  
    fcbptr = (fcb *)text;  
    for(i = 0; i < rbn / sizeof(fcb); i++)  
    {  
        if(fcbptr->free == 0)  
            break;  
        fcbptr++;  
    }  
    blkno = findblock();  
    if(blkno == -1)  
        return;  
    (fat1 + blkno)->id = END;  
    (fat2 + blkno)->id = END;  
  
    now = time(NULL);  
    nowtime = localtime(&now);  
    strcpy(fcbptr->filename, fname);  
    strcpy(fcbptr->exname, exname);  
    fcbptr->attribute = 0x00;  
    fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;  
    fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;  
    fcbptr->first = blkno;  
    fcbptr->length = 0;  
    fcbptr->free = 1;  
    openfilelist[curdir].count = i * sizeof(fcb);  
    do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);  
    fcbptr = (fcb *)text;  
    fcbptr->length = openfilelist[curdir].length;  
    openfilelist[curdir].count = 0;  
    do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);  
    openfilelist[curdir].fcbstate = 1;  
}  
void my_rm(char *filename)  
{  
    fcb *fcbptr;  
    fat *fat1, *fat2, *fatptr1, *fatptr2;  
    char *fname, *exname, text[MAXTEXT];  
    unsigned short blkno;  
    int rbn, i;  
    fat1 = (fat *)(myvhard + BLOCKSIZE);  
    fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);  
    fname = strtok(filename, ".");  
    exname = strtok(NULL, ".");  
    if(strcmp(fname, "") == 0)  
    {  
        printf("Error,removing file must have a right name.\n");  
        return;  
    }  
    if(!exname)  
    {  
        printf("Error,removing file must have a extern name.\n");  
        return;  
    }  
    openfilelist[curdir].count = 0;  
    rbn = do_read(curdir, openfilelist[curdir].length, text);  
    fcbptr = (fcb *)text;  
    for(i = 0; i < rbn / sizeof(fcb); i++)  
    {  
        if(strcmp(fcbptr->filename, fname) == 0 && strcmp(fcbptr->exname, exname) == 0)  
            break;  
        fcbptr++;  
    }  
    if(i == rbn / sizeof(fcb))